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1 pages, 144 KiB

Open AccessEditorial

Statement of Peer Review

by Tom Willems and Okko Bleeker

Eng. Proc. 2023, 54(1), 62; https://doi.org/10.3390/engproc2023054062 - 07 Feb 2024

Viewed by 357

Abstract

In submitting conference proceedings to Engineering Proceedings, the volume editors of the proceedings certify to the publisher that all papers published in this volume have been subjected to peer review administered by the volume editors [...] Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

4 pages, 835 KiB

Open AccessEditorial

Preface: The European Navigation Conference 2023 (ENC 2023)

by Tom Willems and Okko Bleeker

Eng. Proc. 2023, 54(1), 63; https://doi.org/10.3390/engproc2023054063 - 07 Feb 2024

Viewed by 459

Abstract

The European Navigation Conference 2023 (ENC 2023) took place at the European Space Research and Technology Centre (ESTEC) of the European Space Agency (ESA) in Noordwijk, The Netherlands, from 31 May until 2 June 2023 [...] Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2941 KiB

Open AccessProceeding Paper

Quad-Band Multi-Constellation Global Navigation Satellite System Receiver Development Platform with System-on-Chip Architecture

by Muhammad Saad, Fabio Garzia, Szu-Jung Wu, Iñigo Cortés, Frank Förster, Matthias Overbeck, Santiago Urquijo and Wolfgang Felber

Eng. Proc. 2023, 54(1), 1; https://doi.org/10.3390/ENC2023-15439 - 29 Oct 2023

Viewed by 350

Abstract

GNSS receivers with multi-system and multi-frequency capabilities allow more reliable positioning, especially in challenging environments. However, increased available systems and signals lead to hardware resource allocation problems. This issue escalates when ten correlators per tracked GNSS signal are used. Moreover, the communication interface [...] Read more.

GNSS receivers with multi-system and multi-frequency capabilities allow more reliable positioning, especially in challenging environments. However, increased available systems and signals lead to hardware resource allocation problems. This issue escalates when ten correlators per tracked GNSS signal are used. Moreover, the communication interface between the PL and the PS affects the time complexity and challenges the capability of the maximum number of tracking channels. This paper presents the GOOSE v2, a MPSoC-based GNSS receiver, which is composed of a quad-band (L1, L2, L5/E5 and S band) RFFE and baseband digital signal processing. The SoC includes a quad-core 64-bit processor and an FPGA. The on-chip communication between the processors and the FPGA offers high bandwidth, significantly reducing the time complexity. The preliminary evaluation of this new receiver platform shows that, in addition to the legacy signals, it supports NavIC L5 and S-band signals. Furthermore, this receiver closes the tracking loops faster than its legacy version (GOOSE v1), opening the door to implementing more complex algorithms requiring higher time complexity. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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7686 KiB

Open AccessProceeding Paper

Multi-Constellation/Multi-Frequency GNSS Signal Degradation Due to Foliage and Reflective Environments

by Uttama Dutta and Jan Johansson

Eng. Proc. 2023, 54(1), 2; https://doi.org/10.3390/ENC2023-15454 - 29 Oct 2023

Viewed by 318

Abstract

Present day GNSS offers a variety of signals from different satellite constellations and at various frequencies. This paper is based on the work conducted in the project SiL 2.0 and will focus on the study of multi-constellation/multi-frequency GNSS signals as received on top [...] Read more.

Present day GNSS offers a variety of signals from different satellite constellations and at various frequencies. This paper is based on the work conducted in the project SiL 2.0 and will focus on the study of multi-constellation/multi-frequency GNSS signals as received on top of construction equipment as part of the SiL 2.0 dissemination solution. This paper aims to study the impact of foliage and reflective environments on the various signals of multi-constellation GNSS with a focus on GPS and Galileo. Signal strength indicators (SSI) have been used as a measure to understand the shadowing environment around a stationary GNSS antenna mounted on an excavator. It is quite clear from the analysis that traditional GPS L2 signals, C2W and L2W, are weaker in strength than the L2C and L1 C/A signals, and this is found to be consistent for all of the GPS satellites. The effect of signal degradation due to bending over sharp metallic edges is also discussed. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1501 KiB

Open AccessProceeding Paper

Design of a Signaling Scheme for Three Equal-Power Signals in a New Navigation Satellite System

by Hyoungsoo Lim

Eng. Proc. 2023, 54(1), 3; https://doi.org/10.3390/ENC2023-15469 - 29 Oct 2023

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Abstract

Design methods are presented for chip pulses and a constant envelope multiplexing (CEM) scheme for a new navigation satellite system in the S band. If we assume three equal-power signals are needed to transmit, the chip pulses of at least two signals can [...] Read more.

Design methods are presented for chip pulses and a constant envelope multiplexing (CEM) scheme for a new navigation satellite system in the S band. If we assume three equal-power signals are needed to transmit, the chip pulses of at least two signals can have two or more sample magnitudes for a high CEM power efficiency. Considering a case with two dual-magnitude signals, we can find the magnitude values for a target efficiency and then design the magnitude and sign patterns. We analyze the interference for all possible chip pulse sets and sorted them according to selected priorities. We also consider spectral separation between two different signal groups for a flexible operation. The design methods and the results provided in this paper can be a good reference for the signal design of a new navigation satellite system. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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459 KiB

Open AccessProceeding Paper

Galileo Performance Improvements Employing Meta-Signals—Robustness Analysis against Payload and Receiver Distortions

by Florian C. Beck, Christoph Enneking, Steffen Thölert and Michael Meurer

Eng. Proc. 2023, 54(1), 4; https://doi.org/10.3390/ENC2023-15472 - 29 Oct 2023

Cited by 1 | Viewed by 323

Abstract

A concept that has been explored as a means to obtain decimeter-level positioning accuracy with global navigation satellite systems (GNSSs) is meta-signal processing (MSP), which treats several stand-alone GNSS signals as a single composite wideband signal. BeiDou Navigation Satellite System (BDS) III already [...] Read more.

A concept that has been explored as a means to obtain decimeter-level positioning accuracy with global navigation satellite systems (GNSSs) is meta-signal processing (MSP), which treats several stand-alone GNSS signals as a single composite wideband signal. BeiDou Navigation Satellite System (BDS) III already offers with the B1I+B1C signal a meta-signal, while the forthcoming Galileo (GAL) E1D could be combined with E1B or E1C if the E1D signal is broadcast with a frequency offset to the L1/E1 carrier frequency. This would boost the ranging performance of GAL open service (OS) in the upper L-band through MSP. However, the cross-correlation function (CCF) of meta-signals contain numerous high side-maxima which can, when wrongly identified as the main peak, lead to significant pseudo-range errors of multiple meters. The probability of such a false lock is known to increase with decreasing signal-to-noise ratios but can significantly increase even further due to imperfections in the analog hardware components (e.g., linear and non-linear effects of a high-power amplifier (HPA), an output multiplexer (OMUX), a transmitter filter, and a front-end receiver), as these can distort the CCF. One remaining question is whether meta-signals are a well-suited approach to reliably increase ranging performance in the presence of payload and receiver distortions. This study presents the first systematic assessment of the robustness of several potential meta-signal options enabled by a forthcoming GAL E1D signal for different levels of distortion. The results show significant performance gains but also indicate constraints regarding the choice of signals when considering MSP under the influence of distortions. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2317 KiB

Open AccessProceeding Paper

Radar Absolute Positioning

by Chris Hargreaves, Alan Grant and Lydia Hyde

Eng. Proc. 2023, 54(1), 5; https://doi.org/10.3390/ENC2023-15419 - 29 Oct 2023

Viewed by 277

Abstract

The General Lighthouse Authorities (GLA) R&D Directorate has, for some time, advocated that alternate position navigation and timing (PNT) systems should be established to offset critical dependency on Global Navigation Satellite Systems (GNSS), both in the maritime world and across wider industry. The [...] Read more.

The General Lighthouse Authorities (GLA) R&D Directorate has, for some time, advocated that alternate position navigation and timing (PNT) systems should be established to offset critical dependency on Global Navigation Satellite Systems (GNSS), both in the maritime world and across wider industry. The maritime world already has a number of viable systems that may provide a ship’s navigator with position-fixing information independent of GNSS. A promising option is radar. Depending on size, merchant vessels are required to fit radar operating in the X-band (9 GHz) and, optionally S-band (3 GHz). The radar return from the shoreline provides a unique and identifiable fingerprint that depends on the location of the vessel. GRAD has developed a number of different processes that can convert a series of images from the ship’s radar into a series of output position-fixes, independent of having access to satellite (GNSS) positioning. This report describes the methods we investigated and presents the results from a number of ship trials. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1892 KiB

Open AccessProceeding Paper

Preliminary Field Results of a Dedicated 5G Positioning Network for Enhanced Hybrid Positioning

by José A. del Peral-Rosado, Ali Y. Yildirim, Nils C. Klinger, Patric Nolle, Sara M. Razavi, Sagar Parsawar, Rakesh Mundlamuri, Florian Kaltenberger, Niilo Sirola, Stefano Garlaschi, Luca Canzian, Jukka Talvitie and Detlef Flachs

Eng. Proc. 2023, 54(1), 6; https://doi.org/10.3390/ENC2023-15432 - 29 Oct 2023

Cited by 1 | Viewed by 335

Abstract

Dedicated fifth generation (5G) positioning networks are envisaged as a key technology to complement Global Navigation Satellite Systems (GNSS) in challenging situations, such as safety-critical automotive and aerial applications. These 5G networks are explicitly designed to fulfil the positioning needs in a specific [...] Read more.

Dedicated fifth generation (5G) positioning networks are envisaged as a key technology to complement Global Navigation Satellite Systems (GNSS) in challenging situations, such as safety-critical automotive and aerial applications. These 5G networks are explicitly designed to fulfil the positioning needs in a specific environment, by using dedicated pilot signals and locating the base stations (BSs) in favorable conditions for user reception. To prove this concept, the Hybrid Overlay Positioning with 5G and GNSS (HOP-5G) testbed demonstrates the enhanced positioning capabilities resulting from the deployment of ground and aerial BSs. This paper presents a preliminary assessment of the first real-time ranging measurements obtained with a flying BS in a dedicated 5G positioning network. Under hovering and optimal conditions, field results obtained over an 80 MHz downlink bandwidth indicate a ranging precision below 1 m in 95% of cases. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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774 KiB

Open AccessProceeding Paper

Comparison of NeQuick G and Klobuchar Model Performances at Single-Frequency User Level

by Ulrich Ngayap, Claudia Paparini, Marco Porretta, Peter Buist, Knut Stanley Jacobsen, Michael Dähnn, Natalia Hanna, Dzana Halilovic, Anna Świątek and Paulina Gajdowska

Eng. Proc. 2023, 54(1), 7; https://doi.org/10.3390/ENC2023-15475 - 29 Oct 2023

Viewed by 269

Abstract

In this study, the NeQuick G and Klobuchar models are evaluated by monitoring performance issues related to ionosphere activity for single-frequency users. The effects of radio frequency (RF) signal propagation through the ionosphere may have a significant impact on satellite communication and navigation [...] Read more.

In this study, the NeQuick G and Klobuchar models are evaluated by monitoring performance issues related to ionosphere activity for single-frequency users. The effects of radio frequency (RF) signal propagation through the ionosphere may have a significant impact on satellite communication and navigation systems because of geomagnetic field geometry near the magnetic equator and in the proximity to the high- and low-latitude zones. An ongoing challenge is determining how accurate the ionospheric models employed by existing Global Navigation Satellite Systems (GNSSs) are. This work investigates the patterns of total electron content (TEC) fluctuations over distinct zones from 1 January 2019 to 30 June 2022. Measurements are collected at station networks deployed worldwide. Firstly, monthly and seasonal variations of TECs are analysed. Secondly, the TEC ’availability’ parameter, as the percentage of time when the TEC error is compliant with the specification of the Galileo Single-Frequency Ionosphere Algorithm (’NeQuick G’ model), is introduced. The TEC error defines the difference between (a) the model TEC, obtained by either the NeQuick G or the Klobuchar model over a given station, and (b) the reference TEC, based on observations from networks of GNSS receivers. Finally, the position, velocity, and time (PVT), along with broadcast group delays (BGDs) are analysed and the PVT accuracy is compared between the NeQuick G and Klobuchar models. In 3.5 years, the seasonal behaviour of TEC shows maxima during the March and October equinox and minima during the June and December solstice. Moreover, an increase in the TEC values and the amount of TEC errors are visible as we are approaching the next solar maximum. Preliminary results show a larger associated positioning error using the Klobuchar than the NeQuick G model. However, the difference is zone-dependent, most evident in equatorial regions. This collaborative study of the GRC, NMA, TUW, and SRC was performed under the Framework Partnership Agreements (GSA/GRANT/04/2016). Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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3835 KiB

Open AccessProceeding Paper

Assessing the High-Accuracy Service at High Latitudes

by Melania Susi, Daniele Borio, Althaf Azeez, Jihye Park, Kinga Wezka and Ignacio Fernandez-Hernandez

Eng. Proc. 2023, 54(1), 8; https://doi.org/10.3390/ENC2023-15421 - 29 Oct 2023

Viewed by 448

Abstract

The Galileo High-Accuracy Service (HAS) was declared operational (initial service) in January 2023 after an intense testing phase aimed at assessing its service performance through the transmission of live HAS corrections. The HAS performance at high latitudes is evaluated by analyzing data collected [...] Read more.

The Galileo High-Accuracy Service (HAS) was declared operational (initial service) in January 2023 after an intense testing phase aimed at assessing its service performance through the transmission of live HAS corrections. The HAS performance at high latitudes is evaluated by analyzing data collected at the Polish Polar Station located in Hornsund, in the Norwegian Svalbard archipelago. At such a location, the reception conditions can be affected by poor satellite geometries and ionospheric scintillation may degrade the signal quality. In this respect, data affected by scintillation events were identified and used for the performance analysis. The assessment is carried out by comparing the HAS corrections with the International GNSS Service (IGS) precise products. Moreover, the retrieved HAS corrections are used to assess the Precise Point Positioning (PPP) performance. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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3575 KiB

Open AccessProceeding Paper

Development of a Custom GNSS Software Receiver Supporting Supercorrelation

by Javier Gonzalo Garcia, Johannes Rossouw van der Merwe, Paulo Esteves, Dana Jamal, Samir Benmendil, Chris Higgins, Rose Grey, Eugene Coetzee and Ramsey Faragher

Eng. Proc. 2023, 54(1), 9; https://doi.org/10.3390/ENC2023-15423 - 29 Oct 2023

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Abstract

Mitigating multipath interference is one of the biggest challenges in radio positioning. The Supercorrelation™ technology developed via Focal Point Positioning (FPP) suppresses multipath interference by performing long coherent integration while undergoing complex motion in order to isolate the Line-Of-Sight (LOS) signals from the [...] Read more.

Mitigating multipath interference is one of the biggest challenges in radio positioning. The Supercorrelation™ technology developed via Focal Point Positioning (FPP) suppresses multipath interference by performing long coherent integration while undergoing complex motion in order to isolate the Line-Of-Sight (LOS) signals from the unwanted multipath interference. This article presents the current status of a Supercorrelating Global Navigation Satellite System (GNSS) Software-Defined Radio (SDR) and a systematic testing framework. The SDR receiver is capable of real-time processing and facilitates independent testing and demonstrations. The testing framework uses synthetic signals with a Spirent Radio-Frequency Constellation Simulator (RFCS) with Sim3D to create controlled and repeatable scenarios. The initial results demonstrate the benefits of Supercorrelator Technology (S-GNSS) for navigation resilience. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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10924 KiB

Open AccessProceeding Paper

Achieving Sub-Decimeter Accuracy with the Galileo High Accuracy Service: Results from GMV’s HAS Positioning Engine

by Adrián Chamorro, Jorge Rocamora, Simón Cancela and Jesús David Calle

Eng. Proc. 2023, 54(1), 10; https://doi.org/10.3390/ENC2023-15427 - 29 Oct 2023

Cited by 5 | Viewed by 189

Abstract

High-accuracy (HA) positioning services allow users to achieve sub-decimeter-level positioning accuracy. Although these kinds of services are not new, the market is showing great interest in exploiting them for new applications within the mass-market domain. This growing interest is causing a change in [...] Read more.

High-accuracy (HA) positioning services allow users to achieve sub-decimeter-level positioning accuracy. Although these kinds of services are not new, the market is showing great interest in exploiting them for new applications within the mass-market domain. This growing interest is causing a change in the paradigm of HA services, moving from niche sectors to applications targeting billions of users. Considering this framework, the Galileo High Accuracy Service (HAS) provides an open-access service based on the provision of high-accuracy corrections transmitted through the Galileo E6-B signal (E6, data component). The data retrieved by the end-user, which includes orbit, clock, and bias corrections, is reconstructed to allow the computation of Precise Point Positioning (PPP) solutions. This paper is focused on the description and results of GMV’s HAS Positioning Engine (HAS-PE) software library which, implements a PPP solution using the HAS corrections transmitted through Galileo Signal-in-Space. A high-level overview of the integration of the HAS in the Positioning Engine software is presented together with user performance assessments based on static and kinematic tests executed to process real data from GNSS receivers in real time. The static tests are performed using the GMV Global station network, which consists of geodetic grade receivers tracking the signal in open-sky locations around the globe. The kinematic tests are performed with a setup consisting of a mass-market receiver and a high-end receiver for obtaining the E6 pages. The PPP solutions are configured to process both Galileo and GPS corrections transmitted through the Galileo satellites. The assessment performed includes the computation of a set of performance indicators aimed at the analysis of high-accuracy positioning performances. The results of this assessment show that a PPP user taking advantage of this Galileo HAS initial service may easily achieve decimeter-level accuracy on the horizontal and vertical components. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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10 pages, 3364 KiB

Open AccessProceeding Paper

Addressing the Potential of L5/E5a Signals for Road ITS Applications in GNSS-Harsh Environments

by Amarildo Haxhi, Manos Orfanos, Harris Perakis and Vassilis Gikas

Eng. Proc. 2023, 54(1), 11; https://doi.org/10.3390/ENC2023-15430 - 06 Dec 2023

Viewed by 366

Abstract

This study explores the potential of satellite signals L5, E5a and B2a tracked by contemporary Android smartphones. Particularly, the objective is to investigate their performance capabilities and vulnerabilities concerned with L1, E1 and B1 bandwidths and a focus on land vehicle ITS (Intelligent [...] Read more.

This study explores the potential of satellite signals L5, E5a and B2a tracked by contemporary Android smartphones. Particularly, the objective is to investigate their performance capabilities and vulnerabilities concerned with L1, E1 and B1 bandwidths and a focus on land vehicle ITS (Intelligent Transportation Systems) applications aiming to address low to medium PVT (Positioning, Velocity and Timing) solutions. In this regard raw, kinematic GNSS measurements from two Android smartphones were collected (Xiaomi Mi 8 and One Plus Nord 2 5G) under GNSS-harsh environments. The Single Point Positioning (SPP) technique was adopted for processing the single-frequency, multi-constellation raw GNSS measurements through an Extended Kalman Filter (EKF). The results obtained indicate the benefits and difficulties of exploiting modernized GNSS signals for road ITS applications. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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584 KiB

Open AccessProceeding Paper

A Review of GNSS Carrier Phase Ambiguity Resolution and Conceptual AI-Driven Approaches

by Amarildo Haxhi and Vassilis Gikas

Eng. Proc. 2023, 54(1), 12; https://doi.org/10.3390/ENC2023-15431 - 29 Oct 2023

Viewed by 561

Abstract

Precise Point Positioning (PPP) with Integer Ambiguity Resolution (IAR) is an effective way of improving the overall performance of the PPP technique both in terms of convergence time and accuracy. Even though PPP-IAR has seen a tremendous development in the last two decades, [...] Read more.

Precise Point Positioning (PPP) with Integer Ambiguity Resolution (IAR) is an effective way of improving the overall performance of the PPP technique both in terms of convergence time and accuracy. Even though PPP-IAR has seen a tremendous development in the last two decades, there is still room for improvement. Specifically, the search stage of candidate carrier phase ambiguities is characterized as an NP-hard problem that requires a long processing time, leading to limitation in the reliability of the identified optimal solution. A field that would have an impact on the search process of carrier phase ambiguities, and is addressed conceptually in this paper, is Artificial Intelligence (AI). Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2166 KiB

Open AccessProceeding Paper

Cycle Slip Detection of Single-Frequency Measurements in Drone Platforms

by Chan-hee Lee and Euiho Kim

Eng. Proc. 2023, 54(1), 13; https://doi.org/10.3390/ENC2023-15436 - 29 Oct 2023

Cited by 1 | Viewed by 250

Abstract

For the precise operation of Unmanned Aerial Vehicles (UAV), Real-Time Kinematic (RTK) techniques of Global Navigation Satellite System (GNSS) have been used as a positioning source. In a typical drone platform with a low-cost multi-frequency receiver, there are several dual-frequency measurements and a [...] Read more.

For the precise operation of Unmanned Aerial Vehicles (UAV), Real-Time Kinematic (RTK) techniques of Global Navigation Satellite System (GNSS) have been used as a positioning source. In a typical drone platform with a low-cost multi-frequency receiver, there are several dual-frequency measurements and a small set of single-frequency measurements at one time. In this paper, considering the measurement characteristics, we introduce a novel method that aims to detect a cycle slip of a small set of single-frequency measurements using dual-frequency measurements of other satellites. The performance of the proposed single-frequency cycle slip detection methods is compared with a conventional Doppler-based approach using flight test data of a drone platform. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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892 KiB

Open AccessProceeding Paper

The Galileo High-Accuracy Service: Evaluating the Quality of the Corrections and Initial PPP Performance

by Camille Parra, Andreas Schütz, Urs Hugentobler, Thomas Pany and Stefan Baumann

Eng. Proc. 2023, 54(1), 14; https://doi.org/10.3390/ENC2023-15450 - 29 Oct 2023

Cited by 1 | Viewed by 345

Abstract

The Galileo High-Accuracy Service (HAS) is providing free Precise Point Positioning (PPP) corrections for Galileo and GPS satellites through the E6b signal and the internet. Currently, HAS should provide a horizontal and vertical 95% accuracy below 20 centimetres and 40 centimetres, respectively. To [...] Read more.

The Galileo High-Accuracy Service (HAS) is providing free Precise Point Positioning (PPP) corrections for Galileo and GPS satellites through the E6b signal and the internet. Currently, HAS should provide a horizontal and vertical 95% accuracy below 20 centimetres and 40 centimetres, respectively. To assess the accuracy of the current HAS corrections, software has been developed to receive, decode and use HAS corrections. HAS corrections were acquired in the Munich area (Germany) during two sessions in November 2022 and April 2023. The decoder was validated by comparing recorded corrections to data from the Galileo High Accuracy Reference Algorithm and User Terminal (HAUT). Then, the availability and quality of HAS corrections were analysed. The use of orbit and clock corrections significantly improves the broadcast product accuracy; for instance, the Galileo orbit RMS error decreases up to 43% and the GPS RMS up to 80%. The code bias accuracy is at sub-nanosecond level. Finally, to validate the use of HAS corrections, PPP positioning has been achieved. For the used station network, we reached a 95% horizontal and vertical accuracy of 19 cm and 34 cm, respectively, for the kinematic and bi-constellation positioning matching with targeted HAS performances. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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969 KiB

Open AccessProceeding Paper

Estimating Satellite Navigation Broadcast Ephemeris via Inter-Satellite and Ground-to-Satellite Ranging

by Andrea Testa, Grzegorz Michalak, Manuele Dassié, Karl Hans Neumayer and Gabriele Giorgi

Eng. Proc. 2023, 54(1), 15; https://doi.org/10.3390/ENC2023-15463 - 29 Oct 2023

Viewed by 283

Abstract

This paper investigates the potential of performing orbit determination directly in the Earth-fixed frame based on Inter-Satellite Ranging (ISR) measurements as primary observables, combined with Ground-to-Satellite Ranging (GSR) measurements from a small regional ground network. Current Global Navigation Satellite Systems (GNSSs) use L-band [...] Read more.

This paper investigates the potential of performing orbit determination directly in the Earth-fixed frame based on Inter-Satellite Ranging (ISR) measurements as primary observables, combined with Ground-to-Satellite Ranging (GSR) measurements from a small regional ground network. Current Global Navigation Satellite Systems (GNSSs) use L-band pseudo-range and carrier phase measurements from global or regional ground station networks to perform dynamic Orbit Determination and Time Synchronization (ODTS), whereas sparse Satellite Laser Ranging measurements are mainly used for validation. Future GNSSs may be equipped with inter-satellite links (ISLs) to enable inter-satellite clock offset estimation, ranging and data relay. These capabilities carry the potential to significantly improve ODTS procedures. In this work, we assume a fully connected constellation via pair-wise ISLs, with measurement topology assigned by appropriate link schedulers. The satellite orbits are parametrized with the standard 15 Galileo broadcast perturbed Keplerian elements, estimated by using ISR and GSR measurements. This processing strategy eliminates the complex modeling of gravitational and non-gravitational forces, making it particularly suitable for on-board applications and offering an alternative to classical GNSS orbit determination processing architectures. The proposed orbit determination scheme can be used in case of a ground segment failure as a back-up procedure to estimate the orbits of the GNSS satellites onboard of each satellite and guaranteeing a continuous navigation message generation for the system users. The performance of the proposed method depends on a number of factors, such as the length of the data fitting interval, the measurement quality (precision and accuracy), the scheduling and geometry of ISR and GSR measurements, the number and distribution of ground stations, and the accuracy of the ground station coordinates. Preliminary results show that an orbit-only Signal-in-Space Range Error (SiSRE) in the order of 7–9 cm can be obtained by processing 2 to 3 h data with a limited set of supporting ground stations. In this study, the orbit determination scheme proposed is tested on different scenarios, providing a first assessment of attainable performance. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2299 KiB

Open AccessProceeding Paper

Breaking the One-Meter Accuracy Level with Smartphone GNSS Data

by Marcus Franz Glaner and Robert Weber

Eng. Proc. 2023, 54(1), 16; https://doi.org/10.3390/ENC2023-15465 - 29 Oct 2023

Viewed by 2274

Abstract

Smartphones are usually equipped with simple, cost-effective GNSS chips and antennas. They provide mainly single-frequency, low-quality, and challenging GNSS measurements. We demonstrate the difficulties of processing raw GNSS data from Android devices and introduce solutions to break the one-meter accuracy level with smartphones [...] Read more.

Smartphones are usually equipped with simple, cost-effective GNSS chips and antennas. They provide mainly single-frequency, low-quality, and challenging GNSS measurements. We demonstrate the difficulties of processing raw GNSS data from Android devices and introduce solutions to break the one-meter accuracy level with smartphones and Precise Point Positioning. With the logged data of a Samsung Galaxy S23+ and a Google Pixel 7 smartphone, a horizontal position accuracy of around one meter and a few decimeters was accomplished, respectively. These results were achieved after about two minutes of convergence time with our open-source software raPPPid in quasi-real-time settings. Furthermore, the corrections provided by the Galileo High-Accuracy Service proved to be sufficient to achieve sub-meter accuracy with smartphones. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1066 KiB

Open AccessProceeding Paper

Testing the Galileo High Accuracy Service User Terminal (HAUT) in Static Scenarios

by Emilio González, Pedro Pintor, Ana Senado, Narayan Dhital, Javier Ostolaza, Carmelo Hernández, Juan Vázquez, Javier de Blas and Stefano Lagrasta

Eng. Proc. 2023, 54(1), 17; https://doi.org/10.3390/ENC2023-15471 - 29 Oct 2023

Viewed by 281

Abstract

In just one year, Spaceopal and its partners developed the Galileo HAS Performance Characterization User Algorithm for the EU Agency for the Space Programme (EUSPA). The Galileo HAS User Terminal (HAUT) hosts the Galileo HAS Performance Characterization User Algorithm. The Galileo HAS User [...] Read more.

In just one year, Spaceopal and its partners developed the Galileo HAS Performance Characterization User Algorithm for the EU Agency for the Space Programme (EUSPA). The Galileo HAS User Terminal (HAUT) hosts the Galileo HAS Performance Characterization User Algorithm. The Galileo HAS User Terminal is a portable, configurable and autonomous device powered by a triple-frequency Galileo and GPS receiver and calculates a single- (Galileo) or multi-constellation (Galileo + GPS) Galileo HAS and Open Service (OS) positioning, velocity and time (PVT) solution. The User Terminal can be configured to retrieve Galileo HAS corrections either from Galileo Signal-in-Space (SIS) over E6-B or Internet Data Distribution (IDD) over NTRIP in an RTCM3 format and works in different frequency combinations that can be configured by the user. The User Terminal is a robust device (IP64) with multiple communication and logging capabilities. The Galileo HAS Initial Service was declared on 24 January by the European Commission, and provides free-of-charge, high-accuracy Precise Point Positioning (PPP) corrections (orbits, clocks) and code biases for Galileo and GPS to achieve real-time improved user positioning performance. The Galileo HAS Service Definition Document (SDD) and the HAS SIS Interface Control Document (HAS SIS ICD) are freely available to users on the web portal of the European GNSS Service Centre and HAS Internet Data Distribution Interface Control Documents (HAS IDD ICD) are available after registration. Using the Galileo HAS User Terminal, this article presents the results of Galileo HAS User Terminal’s performance, configuring the User Algorithm to assume static dynamics. It is to be noted that this configuration provides a significant performance benefit with respect to a configuration compatible with kinematic operation. Preliminary results indicate the Galileo HAS User Terminal achieves excellent accuracy. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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4919 KiB

Open AccessProceeding Paper

GNSS Radio Frequency Interference Mitigation in Collins Commercial Airborne Receivers

by Angelo Joseph, Patrick Bartolone, Joseph Griggs, Bernard Schnaufer, Huan Phan and Vikram Malhotra

Eng. Proc. 2023, 54(1), 18; https://doi.org/10.3390/ENC2023-15420 - 29 Oct 2023

Viewed by 655

Abstract

Nowadays, commercial aeronautical Global Navigation Satellite Systems (GNSS) receivers are more and more exposed to Radio Frequency Interference (RFI) threats from GNSS jammers and spoofers. On commercial aircraft GNSS, receiver outputs, in general, are integrated or cross-monitored with other navigation sensors such as [...] Read more.

Nowadays, commercial aeronautical Global Navigation Satellite Systems (GNSS) receivers are more and more exposed to Radio Frequency Interference (RFI) threats from GNSS jammers and spoofers. On commercial aircraft GNSS, receiver outputs, in general, are integrated or cross-monitored with other navigation sensors such as IRS and DME, etc., and, in many cases, the GNSS receiver outputs are used directly by on-board aircraft systems. The advent of modernized dual-frequency and multi-constellation signals will improve the availability and integrity of GNSS receivers in the presence of RFI. To be further resilient to the various types of RFI threats, the airborne GNSS receiver will need to perform additional receiver-based detection/mitigation techniques and should be able to determine position integrity in the presence of spoofers. This paper focuses specifically on two techniques under development that will be incorporated via a field loadable software update to the GLU-2100. The first method, Receiver Autonomous Signal Authentication (RASA), and a second type of technique, Staggered Examination of Non-Trusted Receiver Information (SENTRI). The paper will provide a brief description of the RASA and SENTRI algorithms, followed by results from both simulation and real-world tests. Finally, the limitations of the algorithms will also be provided. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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538 KiB

Open AccessProceeding Paper

On the Quantification of the GNSS Signals’ Quality for RFI Assessment

by Naveed Ahmed

Eng. Proc. 2023, 54(1), 19; https://doi.org/10.3390/ENC2023-15440 - 29 Oct 2023

Viewed by 224

Abstract

The performance of radio-frequency interference (RFI) detection and localization could be improved if they are applied on good quality inputs. RFI assessment is an important aspect of evaluating overall signal quality. The worthiness of a Global Navigation Satellite System (GNSS) receiver output can [...] Read more.

The performance of radio-frequency interference (RFI) detection and localization could be improved if they are applied on good quality inputs. RFI assessment is an important aspect of evaluating overall signal quality. The worthiness of a Global Navigation Satellite System (GNSS) receiver output can be generally quantified by a number of parameters readily available from a receiver. However, such discrete parameters do not give a detailed picture of the quality of the received GNSS signals. Statistical treatment of the received signals both in the absence and presence of interference gives some interesting insight about the data. In this paper, we study if the baseband data from the front-end Analog to Digital Converter (ADC) are normally distributed and if the presence of interference affects the statistical behavior of the distribution, often characterized by its probability density function (PDF) and other related parameters, such as skewness and kurtosis. In the second part of the paper, we study the feasibility of the Shapiro–Wilk (SW) test as a method to study the effect of interference on the GNSS signal while also serving as a potential approach to assess RFI. Skewness and kurtosis are statistical measures used to examine the shape of the distribution of a set of data. The implementation of the Shapiro–Wilk test is also studied, which is a normality test used to check whether a set of data follows a normal distribution. The above approaches have been evaluated using an experiment, where an RTLSDR is used as a reference GNSS receiver and simulated noise is added in the real signals. The data have been logged both in the presence and absence of wideband interference. The obtained results show the potential of the techniques presented for both the quantification of GNSS signal quality and the RFI assessment, alike. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1190 KiB

Open AccessProceeding Paper

Continuous Localization-Assisted Collaborative RFI Detection Using the COTS GNSS Receivers

by Naveed Ahmed

Eng. Proc. 2023, 54(1), 20; https://doi.org/10.3390/ENC2023-15441 - 29 Oct 2023

Viewed by 227

Abstract

Radiofrequency Interference (RFI) is a growing concern for many navigation-reliant applications. The dual benefits of RFI localization are considered: first, it can help with situational awareness by estimating the location of the interference source, and secondly, the results can be used to verify [...] Read more.

Radiofrequency Interference (RFI) is a growing concern for many navigation-reliant applications. The dual benefits of RFI localization are considered: first, it can help with situational awareness by estimating the location of the interference source, and secondly, the results can be used to verify the detection of significant interference. The paper exploits the latter by proposing detection techniques making use of the localization results. The performance of the algorithms is evaluated using an experiment in a controlled lab environment where a wideband interference source is emulated in a UAV-based scenario. The detection results are validated using a reference detector operating in a non-position domain. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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978 KiB

Open AccessProceeding Paper

Robustness Levels of Critical Infrastructures Against Global Navigation Satellite System Signal Disturbances

by André Bos, Merle Snijders, Alexandra Zevenbergen, Kirsten Drost, Hein Zelle and Bas van der Hoeven

Eng. Proc. 2023, 54(1), 21; https://doi.org/10.3390/ENC2023-15443 - 29 Oct 2023

Viewed by 222

Abstract

Resilience against signal disturbances is an important characteristic of GNSS-based PNT solutions. In particular, for critical infrastructures, failure to provide correct PNT information in these domains may have a major societal impact. The Resilience Framework by the Department of Homeland Security (DHS) provides [...] Read more.

Resilience against signal disturbances is an important characteristic of GNSS-based PNT solutions. In particular, for critical infrastructures, failure to provide correct PNT information in these domains may have a major societal impact. The Resilience Framework by the Department of Homeland Security (DHS) provides a set of requirements and guidelines to design a PNT solution of a certain level of resilience. Over the lifetime of the applications, it will be of prime importance to assess the resilience of the PNT solutions on a regular basis. Given how often GNSS-based solutions are being applied, partly automating the assessment process will be needed to make this task feasible. To automate the generative process, a machine-readable structure with well-established meaning is required. In this work, the use of fault trees as a formal system to encode the resilience framework is investigated. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1716 KiB

Open AccessProceeding Paper

Jammertest 2022: Jamming and Spoofing Lessons Learned

by Aiden Morrison, Nadezda Sokolova, Anders Solberg, Nicolai Gerrard, Anders Rødningsby, Harald Hauglin, Thomas Rødningen and Tor Dahlø

Eng. Proc. 2023, 54(1), 22; https://doi.org/10.3390/ENC2023-15445 - 29 Oct 2023

Viewed by 594

Abstract

Jammertest 2022 was a week-long series of satellite navigation and timing signal jamming and spoofing exercises carried out on the Norwegian island of Andøya in September of 2022. Organized via a collaboration between the Norwegian spectrum management authority, defense research establishment, public roads [...] Read more.

Jammertest 2022 was a week-long series of satellite navigation and timing signal jamming and spoofing exercises carried out on the Norwegian island of Andøya in September of 2022. Organized via a collaboration between the Norwegian spectrum management authority, defense research establishment, public roads administration, metrology service, and others, the result was the largest known GNSS jamming and spoofing event open to international collaboration and provided an open-access data and publication policy for participants. This paper reviews the event’s organization, scheduled tests, noteworthy jamming observations, noteworthy spoofing observations, and the unexpected observations found during the event and also presents information on what data are publicly available to interested parties, along with the contact information needed to obtain these data. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2216 KiB

Open AccessProceeding Paper

LO and Calibration Signal Distribution in a Multi-Antenna Satellite Navigation Receiver

by Uwe Stehr, Syed N. Hasnain, Björn Bieske, Marius Brachvogel, Michael Meurer and Matthias A. Hein

Eng. Proc. 2023, 54(1), 23; https://doi.org/10.3390/ENC2023-15447 - 29 Oct 2023

Viewed by 251

Abstract

Due to the low signal power of global navigation satellite signals, the receivers are prone to radio frequency interference. Employing multi-antenna arrays is one method to mitigate such effects, by incorporating spatial processing techniques. The large size of the uniform rectangular arrays prevents [...] Read more.

Due to the low signal power of global navigation satellite signals, the receivers are prone to radio frequency interference. Employing multi-antenna arrays is one method to mitigate such effects, by incorporating spatial processing techniques. The large size of the uniform rectangular arrays prevents their use in applications where installation space is limited. Therefore, we proposed a new approach, namely to split one full array into a number of smaller, spatially distributed, sub-arrays to reduce their size and exploit available installation spaces. This concept challenges the distribution of the local oscillator and calibration signals to the respective sub-arrays. This paper compares qualitatively different design concepts for a satellite navigation receiver with two two-element sub-arrays, installed multiple wavelengths apart from each other, in support of establishing an optimal choice for our intended applications in the automotive sector in terms of electrical performance and required hardware and software efforts. In general, weighing the pros and cons of the different concepts, as discussed in the paper, will assist in optimizing the system design approach for a specific application. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2635 KiB

Open AccessProceeding Paper

Interference Detection, Localization, and Mitigation Capabilities of Controlled Reception Pattern Antenna for Aviation

by Annemarie van Zwol, Jan-Joris van Es, Daniel Kappelle, Hein Zelle, Fennanda Doctor and Yuri Konter

Eng. Proc. 2023, 54(1), 24; https://doi.org/10.3390/ENC2023-15452 - 29 Oct 2023

Viewed by 544

Abstract

Global Navigation Satellite System (GNSS) interference poses an increasing threat for civil aviation, and the detection and mitigation of interferences can help to make the sector more robust. This paper focuses on the detection and mitigation capabilities of a software-based Controlled Reception Pattern [...] Read more.

Global Navigation Satellite System (GNSS) interference poses an increasing threat for civil aviation, and the detection and mitigation of interferences can help to make the sector more robust. This paper focuses on the detection and mitigation capabilities of a software-based Controlled Reception Pattern Antenna (CRPA) as part of a wider study in which different detection and mitigation methods are tested and compared. The proposed CRPA uses eigenvalue decomposition to determine the weight vector and is combined with MUltiple SIgnal Classification (MUSIC) for detection purposes. Simulations are used to test the software CRPA for its robustness against different types of interference in static and dynamic scenarios. The test method and processing pipeline are described. Initial results show the CRPA algorithm under test is capable of detecting and mitigating different types of interferences, and mitigation can help a receiver to maintain a position velocity time (PVT) solution for higher levels of interference power. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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5947 KiB

Open AccessProceeding Paper

GNSS Interference Monitoring and Detection (GIMAD) System

by Enric Obiols-Bernaus, Lorena Tortajada-Ropero, Àngel Creus-Blanch, Antonio González-Novell, Fran Fabra and Gonzalo Seco-Granados

Eng. Proc. 2023, 54(1), 25; https://doi.org/10.3390/ENC2023-15460 - 29 Oct 2023

Viewed by 257

Abstract

In the last few years, gradually more systems have relied on the Global Navigation Satellite System (GNSS) for their correct functioning. These systems include safety-critical applications such as airports or emergency services. Given the wide number of GNSS applications and the current availability [...] Read more.

In the last few years, gradually more systems have relied on the Global Navigation Satellite System (GNSS) for their correct functioning. These systems include safety-critical applications such as airports or emergency services. Given the wide number of GNSS applications and the current availability of affordable and easily configurable Software-Defined Radio (SDR) devices, GNSS has become the target of numerous Radio Frequency Interference (RFI) attacks. Thus, RFI has become a real threat for GNSS and, hence, for those systems relying on it. With the purpose of detecting, characterizing, and localizing RFI not only in GNSS frequency bands but also in other daily-used frequency bands, a GNSS Interference Monitoring and Detection (GIMAD) prototype has been developed, with special emphasis on its deployment in safety-critical environments such as airports. GIMAD contemplates European Geostationary Navigation Overlay Service (EGNOS) V3 and International Civil Aviation Organization (ICAO) Ground Based Augmentation System (GBAS) RFI masks covering both in-band and out-band RFIs. In addition, GIMAD was tested in a real-field scenario. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1461 KiB

Open AccessProceeding Paper

The Vulnerability of Inland Waterway AIS to GNSS Radio Frequency Interference

by Jakub Steiner, Jakub Havlíček, Tomáš Duša and Günter Heinrichs

Eng. Proc. 2023, 54(1), 26; https://doi.org/10.3390/ENC2023-15461 - 29 Oct 2023

Viewed by 273

Abstract

GNSS is an indispensable source of positioning, navigation and timing for many sectors, including inland waterway transport. Unfortunately, GNSS is also vulnerable to interference, including intentional jamming and spoofing. This paper evaluates the vulnerability of one of the key inland waterway systems—the automatic [...] Read more.

GNSS is an indispensable source of positioning, navigation and timing for many sectors, including inland waterway transport. Unfortunately, GNSS is also vulnerable to interference, including intentional jamming and spoofing. This paper evaluates the vulnerability of one of the key inland waterway systems—the automatic identification system (AIS)—to GNSS jamming and spoofing. The vulnerability is explored via a series of tests conducted in both laboratory and live-sky environments. The results clearly show the negative impact of both types of interference on AIS. The impact included denial of service and reporting of false position. Additionally, the effects on subsequent systems like river information services or nearby vessels are also showcased. The results presented provide valuable insight into the vulnerability of inland waterway transport. The need for understanding the system limitations and vulnerability rises with the increase in the implementation of autonomous systems into the inland waterway sector, as well as other critical infrastructure sectors. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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328 KiB

Open AccessProceeding Paper

Beamforming Techniques for Resilient Navigation with Small Antenna Arrays

by Lucía Pallarés-Rodríguez, Sergi Locubiche-Serra, Guillem Foreman-Campins, Gonzalo Seco-Granados and José A. López-Salcedo

Eng. Proc. 2023, 54(1), 27; https://doi.org/10.3390/ENC2023-15466 - 29 Oct 2023

Cited by 1 | Viewed by 377

Abstract

This paper presents a comparative benchmarking of different beamforming techniques for robust multipath and spoofing mitigation in handheld receivers equipped with a small number of antenna elements. In the field of Global Navigation Satellite Systems (GNSSs), multipath and spoofing have become major sources [...] Read more.

This paper presents a comparative benchmarking of different beamforming techniques for robust multipath and spoofing mitigation in handheld receivers equipped with a small number of antenna elements. In the field of Global Navigation Satellite Systems (GNSSs), multipath and spoofing have become major sources of signal degradation, whereby the presence of closely spaced replicas of the signal of interest hampers the receiver’s performance. Spatial filtering through the use of antenna arrays is one appealing approach to combat these effects. However, the upward trend in device miniaturization poses a serious concern for spatial filtering in handheld devices such as tablets or smartphones, particularly for the case of decimeter-wave signals such as in GNSSs. The terminal size constraints lead to deploying arrays with very few antennas, thus degrading the mitigation performance of the above impairments. This work explores the feasibility of performing robust multipath and spoofing mitigation in GNSS receivers with antenna arrays of very small sizes. Simulation results on four-antenna rectangular and two-antenna linear array distributions are provided, showing that the reduction in array size can be counteracted by the use of advanced beamformers. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2953 KiB

Open AccessProceeding Paper

Performance Characterization of Hexagon|NovAtel’s Robust Dual-Antenna Receiver (RoDAR) during the Norwegian Jamming Trial 2022

by Ali Broumandan and Sandy Kennedy

Eng. Proc. 2023, 54(1), 28; https://doi.org/10.3390/ENC2023-15470 - 29 Oct 2023

Viewed by 355

Abstract

NovAtel has recently leveraged its expertise in both receiver design and anti-jam technology to develop solutions for space- and weight-constrained applications in challenged GNSS environments. Robust Dual-Antenna Receiver (RoDAR), is based on a commercial dual-antenna receiver, originally designed for attitude determination, and employs [...] Read more.

NovAtel has recently leveraged its expertise in both receiver design and anti-jam technology to develop solutions for space- and weight-constrained applications in challenged GNSS environments. Robust Dual-Antenna Receiver (RoDAR), is based on a commercial dual-antenna receiver, originally designed for attitude determination, and employs special firmware to mitigate jammers and spoofers without an increase in size or power consumption. With RoDAR, the multi-frequency, multi-constellation dual-antenna receiver is capable of null-steering at two different frequency bands (e.g., L1 and L5). In September 2022, the Norwegian Public Roads Administration hosted JammerTest, a live, over-the-air broadcast jamming and spoofing test. This paper presents the jamming and spoofing detection and mitigation performance of RoDAR during this live broadcast test. The interference detection provides spectrum monitoring and jamming characterization on all GNSS bands. The mitigation is carried out by steering a null formed on-board the receiver towards a jamming/spoofing source at GPS L1 and L5 bands. The null steering performance is characterized as a function of signal and position availability compared to a non-protected NovAtel receiver. The effectiveness of the anti-jam and anti-spoofing technology is demonstrated using representative complex spoofing and jamming test cases during this event. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1212 KiB

Open AccessProceeding Paper

E1-E6 SDR Platform Based on BladeRF for Testing Galileo-Assisted Commercial Authentication Service

by Rafael Terris-Gallego, Ignacio Fernandez-Hernandez, José A. López-Salcedo and Gonzalo Seco-Granados

Eng. Proc. 2023, 54(1), 29; https://doi.org/10.3390/ENC2023-15428 - 29 Oct 2023

Cited by 1 | Viewed by 443

Abstract

To enhance the robustness of the Global Navigation Satellite System (GNSS) against malicious attacks (e.g., spoofing), the European Galileo is working on new services, like Open Service Navigation Message Authentication (OSNMA), which provides authentication on the navigation bits, or Commercial Authentication Service (CAS), [...] Read more.

To enhance the robustness of the Global Navigation Satellite System (GNSS) against malicious attacks (e.g., spoofing), the European Galileo is working on new services, like Open Service Navigation Message Authentication (OSNMA), which provides authentication on the navigation bits, or Commercial Authentication Service (CAS), which aims to encrypt the spreading code chips. An assisted mode of the latter, named Assisted Commercial Authentication Service (ACAS), is currently under definition by the Galileo program. It uses the Timed Efficient Stream Loss-tolerant Authentication (TESLA) keys provided by OSNMA on the E1-B signal to re-encrypt some fragments of the encrypted E6-C signal, known as Re-Encrypted Code Sequences (RECSs), that are made available in the GNSS Service Centre (GSC). Once downloaded by a compatible receiver, they can be decrypted using the corresponding key and used to perform the correlation with the broadcasted E6-C signal. If that results in a correlation peak, the signal can be authenticated under certain circumstances. However, the probability of detecting this peak depends on the length of these fragments and their periodicity, since they are only provided for certain predefined instants. Indeed, if the receiver relies solely on E6-C signal and has no accurate time reference, this probability is severely degraded. This is why the nominal operating mode proposed for ACAS is to use the estimates provided by E1-B to reduce the uncertainty on the E6-C signal, so that the receiver can know precisely where these fragments are located. In the context of the PAULA project, we have developed a low-cost hardware platform based on bladeRF that allows acquiring both E1-B and E6-C samples synchronously. In this paper, we describe how to set up this platform and we characterise the alignment between the E1-B and E6-C estimates (code phase and Doppler frequency) using the real datasets obtained with such a platform, which is of key importance for the ACAS nominal mode. The results confirm the convenience of using the estimates from the E1-B signal for ACAS. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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906 KiB

Open AccessProceeding Paper

S-TrackS: A Secure Snapshot-Based Solution for Positioning and Timing

by Aram Vroom, Tom van den Oever, Joaquín Gañez Fernandez, Nick van der Hijden, Alexandra Zevenbergen and Bas van der Hoeven

Eng. Proc. 2023, 54(1), 31; https://doi.org/10.3390/ENC2023-15457 - 29 Oct 2023

Viewed by 378

Abstract

With the large-scale usage of satellite navigation, spoofing and jamming are considerable threats to civilian society. Recent developments, such as Galileo’s Open Service Navigation Message Authentication and GPS’s Chimera, mitigate these risks. However, they provide authentication of the navigation message or ranging code, [...] Read more.

With the large-scale usage of satellite navigation, spoofing and jamming are considerable threats to civilian society. Recent developments, such as Galileo’s Open Service Navigation Message Authentication and GPS’s Chimera, mitigate these risks. However, they provide authentication of the navigation message or ranging code, but not a true position in the case of interference. In critical applications, a protected navigation service is desired, such as Galileo’s Public Regulated Service (PRS). PRS provides an access-controlled navigation service for authorized governmental users, with fully encrypted ranging codes and data channels, providing users with higher robustness against interference. The main challenge of implementing PRS on a large scale is the need to protect the cryptographic material that is required to access the PRS signals inside the receiver. For many applications, a stand-alone receiver solution is unnecessary. These applications could use a remote server for PRS. In this methodology, the end-user device has only a radio frequency front-end which sends short samples to a secure server. The (classified) signal processing is then carried out on this secure server, removing the need for the user device to protect cryptographic material. Besides decreasing the device’s security requirements and power consumption, it also allows to utilize the advantages of PRS in applications that would otherwise not be able to use PRS. In this approach the PRS usage authorization would only be required for the server operations, and not for the end-user devices. It furthermore allows for using additional processing power for unaided PRS acquisition in case of interference. Within the Netherlands, a remote server solution is developed by CGI: S-TrackS, making PRS accessible. In this paper, the application of PRS and architecture for various use cases is presented. It is shown that PRS usage based on a remote server is feasible and can increase the robustness for governmental applications. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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3685 KiB

Open AccessProceeding Paper

Exploring the Contribution of PNT LEO Satellites to Precise Positioning Applications

by Jorge Durán, Damián Socías, Enrique Carbonell, Ana González, David Calle and Irma Rodríguez

Eng. Proc. 2023, 54(1), 33; https://doi.org/10.3390/ENC2023-15426 - 29 Oct 2023

Viewed by 395

Abstract

Positioning services based on GNSS (Global Navigation Satellite Systems) have been using MEO satellites designed to guarantee Earth global coverage for decades. This satellite distribution is sometimes complemented with satellites in Inclined Geosynchronous (IGSO) and Geostationary (GEO) Orbits to improve satellite visibility in [...] Read more.

Positioning services based on GNSS (Global Navigation Satellite Systems) have been using MEO satellites designed to guarantee Earth global coverage for decades. This satellite distribution is sometimes complemented with satellites in Inclined Geosynchronous (IGSO) and Geostationary (GEO) Orbits to improve satellite visibility in particular service areas. During recent years, with the advancements and reduction in costs in the deployment of LEO (Low Earth Orbit) constellations, the opportunity of using LEO satellites for PNT (Positioning, Navigation, and Timing) solutions is being studied. This concept opens the possibility to provide high accuracy positioning overcoming the typical drawbacks of RTK (Real-Time Kinematics) or PPP (Precise Point Positioning), such as the need for ground infrastructure or long convergence times. The high velocity dynamics of the low orbits can help to cancel the effect of the ionosphere in the signals to be processed at the user level. Therefore, the introduction of LEO satellites together with the classical MEO GNSS constellations could be a solution to reduce the dependency on dense station networks. The size of the LEO constellations and the design of their orbits are key factors to improve the PPP solution. Moreover, both the accuracy and the convergence time of the PPP solution depend also on the quality of the on-board equipment of the satellite, especially on the quality of the atomic clock in terms of stability and noise, and on the quality of the orbit and clock corrections sent to the PPP users. GMV has decades of experience in both GNSS and LEO precise orbit determination (POD) fields and in high-accuracy GNSS applications for different market domains. With this experience, several analyses have been carried out to assess the achievable performance when introducing the processing of LEO signals for high accuracy positioning solutions, contributing to the overall GNSS community. The objective of this paper is to describe the analysis run by GMV with the use of synthetic data simulating GNSS and LEO signals, showing results and the associated assessment of the achievable performance. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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996 KiB

Open AccessProceeding Paper

Analysis of Multipath Code-Range Errors in Future LEO-PNT Systems

by Sibren De Bast, Jean-Marie Sleewaegen and Wim De Wilde

Eng. Proc. 2023, 54(1), 34; https://doi.org/10.3390/ENC2023-15453 - 29 Oct 2023

Viewed by 430

Abstract

In recent years, low-Earth-orbit (LEO) constellations have been proposed for Positioning, Navigation and Timing (PNT) applications. Moreover, a couple of test satellites have already been launched and many more are scheduled in the near future. LEO constellations are characterised by their rapid change [...] Read more.

In recent years, low-Earth-orbit (LEO) constellations have been proposed for Positioning, Navigation and Timing (PNT) applications. Moreover, a couple of test satellites have already been launched and many more are scheduled in the near future. LEO constellations are characterised by their rapid change in geometry in comparison to the current medium-Earth-orbit (MEO) Global Navigation Satellite Systems (GNSSs). In this study, we analyse the impact of this high geometry change rate on the code-range error induced by multipaths. We develop a simulation environment with a static receiver and a nearby large building. We track the multipath signal using classical delay- and phase-locked loops (DLL and PLL). Multiple scenarios are simulated and analysed, comparing different orbit heights, MEO and LEO, and carrier frequencies (L-, S- and C-band). The LEO scenarios show up to 96% less code-range error for fast-changing multipath components. We show that this phenomenon is linked to the large phase delay rate between the direct signal and the multipath components, which is up to 75 times higher for LEO satellites when compared to MEO satellites. The phase delay rate reaches values higher than the DLL bandwidth. As a result, the DLL filters out the errors induced by fast-changing reflected signals, partially eliminating the multipath-induced code-range errors. The presented effect is coupled to the wavelength of the used carrier frequency. Our simulations show a reduction in multipath-induced code-range error for S- and C-band LEO-PNT signals in comparison to L-band signals. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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392 KiB

Open AccessProceeding Paper

Performance Analysis of the Pilot and Data Component of a CSS Signal for LEO-PNT

by Daniel Egea-Roca, José A. López-Salcedo and Gonzalo Seco-Granados

Eng. Proc. 2023, 54(1), 35; https://doi.org/10.3390/ENC2023-15425 - 29 Oct 2023

Viewed by 230

Abstract

From the analysis of chirp spread spectrum (CSS) signals in radar and communication applications, we can distinguish the cases of estimating only data or time-delay propagation or Doppler frequency when all the other parameters are known or set to zero. The case of [...] Read more.

From the analysis of chirp spread spectrum (CSS) signals in radar and communication applications, we can distinguish the cases of estimating only data or time-delay propagation or Doppler frequency when all the other parameters are known or set to zero. The case of estimating all three parameters at the same time has not been treated in the literature of radar or communications. We consider in this paper the use of a CSS signal for a LEO-PNT signal, which perfectly fits with the case of estimating the three parameters mentioned above. Specifically, the main goal of this paper is to explain the design of a CSS signal for PNT. This will include the design of the ranging component and the data component. The performance evaluation of both components will also be analyzed and linked. It is important to note that the focus of this paper will be the data component, and we link it with the pilot component through sensitivity performance. The results given in this paper show the capabilities of CSS for PNT. Previous works have shown accuracies on the level of meters with achievable data rates shown in this paper in the order of tens of kbps. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1909 KiB

Open AccessProceeding Paper

Analysis of Baseband Algorithms for LEO PNT

by Fran Fabra, José A. López-Salcedo and Gonzalo Seco-Granados

Eng. Proc. 2023, 54(1), 36; https://doi.org/10.3390/ENC2023-15458 - 29 Oct 2023

Viewed by 294

Abstract

This paper provides an analysis of the impact of transmitter dynamics on baseband algorithms for position, navigation and timing applications using a low Earth orbit constellation. In particular, the acquisition and tracking of signals with high dynamics have larger Doppler and Doppler drift [...] Read more.

This paper provides an analysis of the impact of transmitter dynamics on baseband algorithms for position, navigation and timing applications using a low Earth orbit constellation. In particular, the acquisition and tracking of signals with high dynamics have larger Doppler and Doppler drift values that might impair the use of standard methods. Our analysis combines a theoretical assessment of acquisition and tracking thresholds with a performance evaluation by means of a simulation. Three frequency bands are tested (UHF, S and Ka) and an open-source software receiver has been adapted for such a purpose. The results obtained show the potential feasibility of LEO-PNT at baseband level under minimal considerations. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2720 KiB

Open AccessProceeding Paper

Lunar Navigation System ODTS Signal in Space Error Analysis

by Cosimo Stallo, Carmine Di Lauro, Mattia Carosi, Laura De Leo, Martina Cappa, Daniele Musacchio, Daniele Cretoni, Henno Boomkamp, Pietro Giordano, Richard Swinden and Javier Traveset

Eng. Proc. 2023, 54(1), 37; https://doi.org/10.3390/ENC2023-15468 - 29 Oct 2023

Cited by 1 | Viewed by 387

Abstract

In recent years, the Moon has gained renewed interest in terms of human exploration for scientific purposes. In this context, Thales Alenia Space is leading a consortium to define the main concepts for a Lunar Radio Navigation System (LRNS) in terms of Orbit [...] Read more.

In recent years, the Moon has gained renewed interest in terms of human exploration for scientific purposes. In this context, Thales Alenia Space is leading a consortium to define the main concepts for a Lunar Radio Navigation System (LRNS) in terms of Orbit Determination and Time Synchronization (ODTS) as part of an ESA Technology Development Element (TDE) programme. This work focuses on the latest performance results achieved through a dedicated simulator in terms of Signal In Space Error (SISE). Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1306 KiB

Open AccessProceeding Paper

Cooperative Swarm Geometry Optimization for Assured Navigation with Range Radios in GNSS-Denied Environments

by Mats Martens and Maarten Uijt de Haag

Eng. Proc. 2023, 54(1), 38; https://doi.org/10.3390/ENC2023-15418 - 29 Oct 2023

Cited by 1 | Viewed by 263

Abstract

This paper addresses cooperative navigation using range radios to enable absolute positioning of low-flying UAS (LF) while operating in GNSS-denied environments. High-flying UAS (HF) are positioned above the denied area and broadcast position reports. These reports, in combination with range measurements from the [...] Read more.

This paper addresses cooperative navigation using range radios to enable absolute positioning of low-flying UAS (LF) while operating in GNSS-denied environments. High-flying UAS (HF) are positioned above the denied area and broadcast position reports. These reports, in combination with range measurements from the LF to the HF, enable absolute positioning of the LF. (1) Methods: As the navigation performance is directly influenced by the geometry of both LF and HF’s relative positions, HF positions shall be optimized such that the Dilution of Precision (DOP) becomes minimal. The authors derive optimal azimuth angle combinations, which guarantee a minimal Horizontal Dilution of Precision (HDOP), and show the error characteristic for sub-optimal configurations, which enables the formulation of multi-vehicle-constrained optimization problems for specific combinations of numbers of HF and LF. (2) Results: An optimization problem is derived and solved for two HF aiding three LF as an example application for the derived rules. (3) Conclusions: The resulting geometry has yielded promising HDOP values, improving navigation performance in GNSS-denied environments. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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618 KiB

Open AccessProceeding Paper

Quantum-Based Relative Inertial Navigation with Velocity-Aided Alignment and Initialization

by Pieter Simke de Vries, Jim Rojer and Floris E. Kalff

Eng. Proc. 2023, 54(1), 39; https://doi.org/10.3390/ENC2023-15437 - 29 Oct 2023

Viewed by 330

Abstract

Quantum sensors are expected to offer significant advantages in magnetic- and gravity-aided navigation. However, these techniques depend on the local environmental conditions and require an alternative solution to ensure high position accuracy on shorter timescales. This paper explores the potential of a hypothetical [...] Read more.

Quantum sensors are expected to offer significant advantages in magnetic- and gravity-aided navigation. However, these techniques depend on the local environmental conditions and require an alternative solution to ensure high position accuracy on shorter timescales. This paper explores the potential of a hypothetical quantum Inertial Measurement Unit (IMU) with much better performance than classical IMUs when used for dead reckoning position estimation preceded by an alignment period to achieve a relative inertial navigation solution. We show that significantly reduced noise levels (velocity random walk) for the accelerometer and/or gyroscope cannot be automatically exploited. In practice, axis misalignment and initial state errors in orientation limit performance. Incorrect orientation causes errors in compensating for the gravity vector, having a dominant effect. This research proposes to introduce an alignment period with a reliable velocity sensor, prior to starting the mission relying solely on inertial navigation. The orientation errors can be estimated with numerical optimization, in which we match the dead reckoning estimate to the reference velocity signal. The fact that quantum IMUs have a much more accurate measurement means that these orientation errors could be compensated much more accurately. When mitigating these dominant error sources, there is a significant benefit to using a quantum IMU for inertial navigation. The initial position error growth is significantly smaller than existing systems. Some estimates are given for the necessary quality of the IMUs to benefit from these protocols and offer a similar position solution quality to high-end or military-grade IMUs. In the future, military operations that do not rely on Global Navigation Satellite System (GNSS) for their Positioning, Navigation and Timing (PNT) information may be performed with unprecedented position accuracy when using a quantum IMU complemented with velocity-aided alignment period, thereby increasing the effectiveness and dependability of the operation. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2600 KiB

Open AccessProceeding Paper

Local Differential GNSS Augmentation for Integration into Urban Air Mobility

by Daniel Gerbeth, Maria Caamano and Chen Zhu

Eng. Proc. 2023, 54(1), 40; https://doi.org/10.3390/ENC2023-15442 - 29 Oct 2023

Viewed by 216

Abstract

This paper describes a concept for local GNSS (Global Navigation Satellite System) augmentation derived from the established Ground Based Augmentation System (GBAS) in civil aviation. The aim of this concept is to provide reliable and accurate GNSS measurements for integration into a redundant, [...] Read more.

This paper describes a concept for local GNSS (Global Navigation Satellite System) augmentation derived from the established Ground Based Augmentation System (GBAS) in civil aviation. The aim of this concept is to provide reliable and accurate GNSS measurements for integration into a redundant, safe and reliable integrated navigation architecture tailored to serve Urban Air Mobility (UAM). The proposed concept for local GNSS augmentation addresses the specific challenges of UAM, in particular for take-off and landing operations, and ensures safe separation between UAM vehicles en route between vertiports. By using less expensive hardware compared to the traditional GBAS, the concept aims to make the integration into future urban airspace easier and more cost-effective, both in terms of ground infrastructure demands and on-board navigation hardware. In addition to the high-level system concept and considerations, we present an initial nominal performance assessment of local augmentation using lower-cost airborne and ground hardware. This assessment is based on actual UAV (Unmanned Aerial Vehicle) flight trials conducted in different urban scenarios, as well as long-term rooftop measurements. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1105 KiB

Open AccessProceeding Paper

IMU and GNSS Postprocessing for High-Resolution Strapdown Airborne Gravimetry

by Vadim Vyazmin and Andrey Golovan

Eng. Proc. 2023, 54(1), 41; https://doi.org/10.3390/ENC2023-15455 - 29 Oct 2023

Viewed by 337

Abstract

Strapdown airborne gravimeters based on a navigation-grade inertial measurement unit (IMU) are highly sensitive to perturbations during aircraft flight, especially in the case of flights in draped mode (at a constant altitude above the terrain) or drone-based flights. This implies the crucial importance [...] Read more.

Strapdown airborne gravimeters based on a navigation-grade inertial measurement unit (IMU) are highly sensitive to perturbations during aircraft flight, especially in the case of flights in draped mode (at a constant altitude above the terrain) or drone-based flights. This implies the crucial importance of postprocessing, including determination of the IMU and GNSS navigation solutions, IMU/GNSS integration, and gravity estimation. In the paper, we briefly outline the key aspects of the developed postprocessing methodology. By processing raw data from two surveys (one is based on a small aircraft and the other on a drone), we investigate the best achievable spatial resolution of strapdown airborne gravimetry. We show that high-accuracy gravity estimates (at sub-mGal level) at a half-wavelength spatial resolution of 1 km can be obtained in the considered surveys. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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7542 KiB

Open AccessProceeding Paper

Experimentation of Monocular Visual-Aided Inertial Navigation on Fixed-Wing Unmanned Aerial Vehicle

by Baheerathan Sivalingam and Ove Kent Hagen

Eng. Proc. 2023, 54(1), 42; https://doi.org/10.3390/ENC2023-15476 - 29 Oct 2023

Viewed by 207

Abstract

This paper presents an experimental study utilizing the vision-aided inertial navigation system (VaINS) on a fixed-wing unmanned aerial vehicle (UAV). VaINS operates as a data-logging box, collecting sensor data, processing them, and transmitting the navigation solution to an operator terminal in real time. [...] Read more.

This paper presents an experimental study utilizing the vision-aided inertial navigation system (VaINS) on a fixed-wing unmanned aerial vehicle (UAV). VaINS operates as a data-logging box, collecting sensor data, processing them, and transmitting the navigation solution to an operator terminal in real time. The flight data contain buildings, vegetation, a river, a lake, and mountains. The camera’s pitch angle was tested at both a grazing angle of 22° and a nadir angle of 90°. The aim of this experiment was twofold: to explore the application of VaINS on a fixed-wing UAV and to assess the performance of the image-aided navigation system. The image-aided inertial navigation system (INS) solution was compared with a reference solution during GNSS-denied time intervals. The camera’s pitch angle at 90° exhibited a slight advantage over the grazing angle at 22°. Moreover, in the linear flight segments, the image-aided navigation system demonstrated significantly better performance compared to the free inertial solution during the GNSS-denied periods. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2587 KiB

Open AccessProceeding Paper

Galileo Receiver Performance Analysis with New I/NAV Improvements Live Data

by Rui D. Nunes, Mahamoudou Ouedraogo, Susanne Schlötzer, Nityaporn Sirikan and Stefan Wallner

Eng. Proc. 2023, 54(1), 43; https://doi.org/10.3390/ENC2023-15422 - 29 Oct 2023

Viewed by 185

Abstract

This work presents the results showing the improvement of the performance of a Galileo receiver processing the new I/NAV words 16–20 and SSP in comparison to the performance using the previous legacy I/NAV configuration. The results were obtained by replaying GNSS signals recorded [...] Read more.

This work presents the results showing the improvement of the performance of a Galileo receiver processing the new I/NAV words 16–20 and SSP in comparison to the performance using the previous legacy I/NAV configuration. The results were obtained by replaying GNSS signals recorded in Urban and Open Sky mobile environments when at least four satellites broadcasting the new words were visible. The results show an improvement of Time to First Fix values using RedCED (word 16) and FEC2 (words 17–20) in cold start conditions and a reduction in time needed to converge using SSP when coarse time (within 3 s error) is available. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2611 KiB

Open AccessProceeding Paper

Reliability of Smartphone Positioning in Harsh Environment

by Giovanni Cappello, Ciro Gioia, Antonio Angrisano, Silvio Del Pizzo, Gabriele Portelli and Salvatore Gaglione

Eng. Proc. 2023, 54(1), 44; https://doi.org/10.3390/ENC2023-15429 - 29 Oct 2023

Viewed by 251

Abstract

Since 2016, it has been possible to record and collect GNSS (Global Navigation Satellite System) raw data on Android devices. This has been a game changer in low-cost device applications. Researchers in the GNSS field have tried to answer new questions regarding Android [...] Read more.

Since 2016, it has been possible to record and collect GNSS (Global Navigation Satellite System) raw data on Android devices. This has been a game changer in low-cost device applications. Researchers in the GNSS field have tried to answer new questions regarding Android device positioning performance, the quality of their measurements, positioning techniques that could be applied, and methods to increase the accuracy and the reliability of the PNT (Position Navigation Timing) solution. Several research groups have demonstrated accurate positioning using smartphones while also showing the potential limitations of such devices. In particular, problems related to the GNSS antenna performance have been reported; indeed, in urban scenarios, where users typically operate, the presence of multiple outliers could make the navigation solution inaccurate, if not unfeasible. Hence, techniques useful for verifying the reliability of the navigation solutions have become fundamental. The reliability of the PNT solution provided by smartphones is an open research question. In this study, traditional RAIM (Receiver Autonomous Integrity Monitoring) algorithms were adapted to the case of smartphones. Navigation solution algorithms, including FDE (Fault Detection and Exclusion), were tested using a long data collection made by a smartphone located in a harsh environment in static mode. The performance of the proposed approaches was assessed in terms of horizontal and vertical errors, solution reliability, and residual distribution. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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10 pages, 3931 KiB

Open AccessProceeding Paper

A Comparative Experimental Performance Assessment of RTK+OSNMA-Based Positioning for Road Vehicle Applications

by Roman Lesjak, Susanne Schweitzer, José M. Vallet García, Karl Diengsleder-Lambauer and Selim Solmaz

Eng. Proc. 2023, 54(1), 45; https://doi.org/10.3390/ENC2023-15434 - 20 Dec 2023

Cited by 1 | Viewed by 395

Abstract

To realize the societal need for greener, safer, and smarter mobility, ambitious technical challenges need to be addressed. With this aim, the H2020-EUSPA project ESRIUM investigates various aspects of highly accurate, reliable, and assured EGNSS localization information for road vehicles with a particular [...] Read more.

To realize the societal need for greener, safer, and smarter mobility, ambitious technical challenges need to be addressed. With this aim, the H2020-EUSPA project ESRIUM investigates various aspects of highly accurate, reliable, and assured EGNSS localization information for road vehicles with a particular focus on automated vehicles. To analyze the achievable accuracy, reliability, and availability of multi-frequency and multi-GNSS mass-market receivers, we have conducted test drives under different GNSS reception conditions. In the tests, special focus was placed on using the Galileo Open Service Navigation Message Authentication (OSNMA) service, offering an additional feature for assured PVT (position, velocity, and time) information with respect to spoofing. We analyzed the performance of three Septentrio Mosaic-X5 receivers operated with different OSNMA settings. It could be shown that strict use of OSNMA provides very good positioning accuracy as long as sufficient suitable satellites are available. However, the overall performance suffers from a reduced satellite number and is therefore limited. The performance of a receiver using authenticated Galileo with GPS signals (final status of Galileo OSNMA) is very good for a mass-market receiver: 92.55% of the solutions had a 2D position error below 20 cm during 8.5 h of driving through different environments. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2558 KiB

Open AccessProceeding Paper

Advanced Receiver Autonomous Integrity Monitoring (ARAIM) for Unmanned Aerial Vehicles

by Merle Snijders, Heiko Engwerda, Javier Fidalgo, Enrique Domínguez, Ginés Moreno, Fulgencio Buendía, Joao Pedro Duque, Jorge Martínez, Ilaria Martini, Matteo Sgammini and Juan Pablo Boyero

Eng. Proc. 2023, 54(1), 46; https://doi.org/10.3390/ENC2023-15435 - 29 Oct 2023

Viewed by 443

Abstract

Advanced Receiver Autonomous Integrity Monitoring (ARAIM) is an evolution of the currently used aviation-focused Global Navigation Satellite System integrity service, Receiver Autonomous Integrity Monitoring (RAIM). Where RAIM supports only lateral navigation, with its adaptations including multiple frequencies and constellations, and with the use [...] Read more.

Advanced Receiver Autonomous Integrity Monitoring (ARAIM) is an evolution of the currently used aviation-focused Global Navigation Satellite System integrity service, Receiver Autonomous Integrity Monitoring (RAIM). Where RAIM supports only lateral navigation, with its adaptations including multiple frequencies and constellations, and with the use of Integrity Support Messages (ISMs), ARAIM also supports vertical guidance. Although these techniques were designed to serve the aviation community, ARAIM could be used in a wide range of applications, especially safety-critical applications. With further evolutions, ARAIM could also be extended to cover more demanding applications in various sectors. This work reports the outcomes of the study of the applicability of ARAIM for the Unmanned Aerial Vehicle (UAV) sector. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2231 KiB

Open AccessProceeding Paper

Precise Positioning for Mass-Market: Optimal Data Dissemination DAB+ Demonstrator

by Delphine Isambert, Paul Chambon, Raphaël Baucry, Christopher Perschke, Jannes Wübbena, Xavier Leblan, Giuseppe Rotondo, Fabien Galtier, Samar Kaddouri and Florin-Catalin Grec

Eng. Proc. 2023, 54(1), 47; https://doi.org/10.3390/ENC2023-15446 - 29 Oct 2023

Viewed by 203

Abstract

The main issue in the development of precise positioning is the way in which to send GNSS corrections. To handle this case, a terrestrial broadcast mechanism based on DAB+ (digital audio broadcasting) signals was chosen to overcome the scalability challenges, as it would [...] Read more.

The main issue in the development of precise positioning is the way in which to send GNSS corrections. To handle this case, a terrestrial broadcast mechanism based on DAB+ (digital audio broadcasting) signals was chosen to overcome the scalability challenges, as it would allow a service provider to transfer assistance data based on a “one-to-many” scheme. DAB is easily widely deployed, with large coverage predictions carried using ATDI’s HTZ simulator. The DAB+ reception demonstrator uses SSRZ, a compressed and compact state space representation corrections format developed by Geo++. SSRZ corrections were generated using data from Teria’s CORS network and have been broadcasted over the air with DAB+ signals. To validate the SSRZ corrections, the “Record&Replay” technique was used. It consists of digitizing GNSS signals during a normal field test. Once data were collected and validated, replays were executed in the laboratory. Different scenarios were set up to validate the accuracy of the position with SSRZ corrections sent via DAB+ and the convergence to the corrected position after ambiguity loss. The results show that the accuracy was acceptable when the user remained close to the transmitting DAB+ antenna (<10 km). The lower performance might result from broadcast limitations in urban environments. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2391 KiB

Open AccessProceeding Paper

European Geostationary Navigation Overlay Service Performance Prediction

by Pieter Bastiaan Ober, Jiri Doubek, Tamás Prajczer, János Nemes, Csongor Fekete, Mickael Dall’Orso and Guillaume Buscarlet

Eng. Proc. 2023, 54(1), 48; https://doi.org/10.3390/ENC2023-15456 - 29 Oct 2023

Viewed by 159

Abstract

The paper describes the development of a machine learning-based system to predict the performance of EGNOS. The system is shown to perform considerably better than existing simple geometry-based ‘macro’ models developed for the same purpose in the past. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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9 pages, 1531 KiB

Open AccessProceeding Paper

Resilience in Maritime Transport for the Next Decade

by Alina Colling and Stephan Procee

Eng. Proc. 2023, 54(1), 49; https://doi.org/10.3390/ENC2023-15416 - 14 Dec 2023

Viewed by 308

Abstract

This vision paper covers the increased complexity of navigational environments and presents an innovative navigation system that can support the human in this task. Shipping in general also requires a mean to support navigators reduce the risk of accidents due to smaller passing [...] Read more.

This vision paper covers the increased complexity of navigational environments and presents an innovative navigation system that can support the human in this task. Shipping in general also requires a mean to support navigators reduce the risk of accidents due to smaller passing distance or a shorter reaction time. An innovative approach called Velocity Obstacles might help the operator to avoid intruding into an object’s protected zone by visualizing the problem space in relation to the maneuvering potential of the Own Ship. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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9816 KiB

Open AccessProceeding Paper

Smart Port Shuttle: Sensor-Based Navigation for Inland Waterway Transportation

by Katrin Dietmayer, Jochen Schwenninger, Himanshu Gupta, Muhammad Saad, Melanie Lipka, Matthias Overbeck and Wolfgang Felber

Eng. Proc. 2023, 54(1), 50; https://doi.org/10.3390/ENC2023-15438 - 29 Oct 2023

Viewed by 272

Abstract

Germany has a wide-meshed waterway network. Although inland navigation is one of the most efficient transportation methods, its share of transport is steadily decreasing. The research project Smart-Port-Shuttle Hildesheim aims to strengthen the waterway system both from the aspect of inland navigation and [...] Read more.

Germany has a wide-meshed waterway network. Although inland navigation is one of the most efficient transportation methods, its share of transport is steadily decreasing. The research project Smart-Port-Shuttle Hildesheim aims to strengthen the waterway system both from the aspect of inland navigation and from the aspect of ports. For this purpose, a holistic approach is chosen, which includes technological innovations on the one hand and integration into a logistical concept on the other. This paper focuses on the first point: a technological approach for a (partially) automated inland vessel. It will present the hardware setup and an evaluation of the sensors at a selection of critical points, such as in a lock, at a bridge passage, or during the passing of an obstacle. Different methods, such as Galileo E5a measurements for positioning or Simultaneous Localization and Mapping (SLAM) for constructing and updating the map of the branch canal, are analyzed. The data structure of the Robot Operating System (ROS) is presented, as the raw data are available to the audience. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1161 KiB

Open AccessProceeding Paper

Required Navigation Performances for Drone Flight Operations

by Pablo Haro, Carmen Aguilera and Giovanni Lucchi

Eng. Proc. 2023, 54(1), 51; https://doi.org/10.3390/ENC2023-15459 - 29 Oct 2023

Viewed by 348

Abstract

Drone flight operations require ensuring the containment of the drone along the desired flight path in the domain of the Total System Error (TSE). The paper proposes a number of Required Navigation Performance (RNP) specifications tailored to drones by assessing the contributing error [...] Read more.

Drone flight operations require ensuring the containment of the drone along the desired flight path in the domain of the Total System Error (TSE). The paper proposes a number of Required Navigation Performance (RNP) specifications tailored to drones by assessing the contributing error sources: the definition of the desired flight path, flyability, autopilot envelope, positioning errors, and operational environment (bottom-up approach). Ongoing work with drone operators is collecting their navigation requirements (top-down approach) in order to determine to which extent RNP navigation specifications meet their requirements along the flight profile. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1700 KiB

Open AccessProceeding Paper

Development of a Global Navigation Satellite System Receiver for Specific Category Unmanned Aerial Systems Operations

by Sergi Dueñas Pedrosa, Samuele Fantinato, Laura García-Junceda del Rio, Esther Lopez, David Abia, Jacopo Marangoni and Sara Molinari

Eng. Proc. 2023, 54(1), 52; https://doi.org/10.3390/ENC2023-15467 - 29 Oct 2023

Cited by 1 | Viewed by 226

Abstract

The DEGREE project is focused on the development of a cutting-edge dual-frequency GNSS receiver intended to achieve optimum performance and take advantage of the EGNSS (European Global Navigation Satellite System), which allows the leveraging of several differentiators in order to safely integrate UASs [...] Read more.

The DEGREE project is focused on the development of a cutting-edge dual-frequency GNSS receiver intended to achieve optimum performance and take advantage of the EGNSS (European Global Navigation Satellite System), which allows the leveraging of several differentiators in order to safely integrate UASs into non-segregated airspace and into the U-Space. In order to meet the requirements for commercial operations purposes, the objective of the DEGREE project is to develop a receiver that could meet the requirements for the high level of robustness required for SAIL IV and beyond, thus unlocking all possible risk levels for operations in the specific category. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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10 pages, 3865 KiB

Open AccessProceeding Paper

Automated Route Planning from LiDAR Point Clouds for Agricultural Applications

by Fabian Theurl, Christoph Schmied, Eva Reitbauer and Manfred Wieser

Eng. Proc. 2023, 54(1), 54; https://doi.org/10.3390/ENC2023-15448 - 12 Dec 2023

Cited by 1 | Viewed by 323

Abstract

This paper develops an algorithm to compute optimal routes for an autonomous compost turner. In commercial composting, the material to be composted is piled up in large heaps called windrows and turned regularly by compost turners. The environment at the composting site is [...] Read more.

This paper develops an algorithm to compute optimal routes for an autonomous compost turner. In commercial composting, the material to be composted is piled up in large heaps called windrows and turned regularly by compost turners. The environment at the composting site is constantly changing, as the locations of the windrows change with each turning procedure. Therefore, we propose a novel method that automatically computes routes on a composting plant from LiDAR data. The LiDAR is mounted on the compost turner together with a dual-antenna GNSS receiver, an IMU, and rotary encoders. An extended Kalman filter is used to obtain the vehicle’s pose. Through direct georeferencing, a global point cloud is obtained. The routing algorithm crops, segments, and filters the point cloud until the points along the ridge of each windrow remain. These points are used to compute the optimal routes along each windrow. Furthermore, a user can select the windrows which need to be turned and the algorithm then computes the most efficient path for the compost turner, which also includes the passages between the windrows. The method was tested within a simulation environment using a 3D model of the composting site. The results show that the algorithm detects the windrows and computes the routes with sufficient accuracy for autonomous compost turning. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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6056 KiB

Open AccessProceeding Paper

Ice Navigation in Arctic Offshore Wind Parks: Traffic Coordination Using Route Exchange and Moving Havens

by Thomas Porathe

Eng. Proc. 2023, 54(1), 55; https://doi.org/10.3390/ENC2023-15462 - 29 Oct 2023

Viewed by 258

Abstract

New areas for the production of fossil-free renewable offshore energy production are planned in Arctic waters in the Bay of Bothnia, in the very north of the Baltic Sea between Sweden and Finland. These are waters normally covered with 30–60 cm of ice [...] Read more.

New areas for the production of fossil-free renewable offshore energy production are planned in Arctic waters in the Bay of Bothnia, in the very north of the Baltic Sea between Sweden and Finland. These are waters normally covered with 30–60 cm of ice every winter and shipping is carried out with icebreaker assistance. This article suggests the need for research on the wind turbine’s effect on ice behavior and ice navigation. Some concepts from previous research are suggested as a solution. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1810 KiB

Open AccessProceeding Paper

Risk-Based UAV Flight Path Optimization in Accordance with SORA

by Jannik Heinze and Maarten Uijt de Haag

Eng. Proc. 2023, 54(1), 56; https://doi.org/10.3390/ENC2023-15473 - 29 Oct 2023

Viewed by 383

Abstract

With the EU regulation of drone operations varying based on the specific type of drone, path planning can be done to consider risk mitigation. This paper proposes a transition-based rapidly exploring random tree star (T-RRT*) path planning algorithm for fixed-wing drone operations over [...] Read more.

With the EU regulation of drone operations varying based on the specific type of drone, path planning can be done to consider risk mitigation. This paper proposes a transition-based rapidly exploring random tree star (T-RRT*) path planning algorithm for fixed-wing drone operations over rural areas. Risk is decoded in the cost function, which mainly considers population density and special infrastructure types. It was found that the algorithm is capable of finding paths that minimize exposure of the general population and infrastructure. However, path and computational inefficiencies were found. Usage of another data structure or algorithm might improve performance. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2558 KiB

Open AccessProceeding Paper

Realism-Oriented Design, Verification, and Validation of Novel Robust Navigation Solutions

by Sorin Andrei Negru, Patrick Geragersian, Ivan Petrunin, Raphael Grech and Guy Buesnel

Eng. Proc. 2023, 54(1), 57; https://doi.org/10.3390/ENC2023-15424 - 29 Oct 2023

Cited by 1 | Viewed by 389

Abstract

Urban environments are characterized by a set of conditions underpinning degradation Position, Navigation and Timing (PNT) signals, such as multipath and non-line of sight (NLOS) effects, negatively affecting the position and the navigation integrity during the Uncrewed Aerial Vehicles (UAVs) operations. Before the [...] Read more.

Urban environments are characterized by a set of conditions underpinning degradation Position, Navigation and Timing (PNT) signals, such as multipath and non-line of sight (NLOS) effects, negatively affecting the position and the navigation integrity during the Uncrewed Aerial Vehicles (UAVs) operations. Before the deployment of such uncrewed aerial platforms, a realistic simulation set-up is required, which should facilitate the identification and mitigation of the performance degradation that may appear during the actual mission. This paper presents the case study of the development of a robust Artificial Intelligence (AI)-based multi-sensor fusion framework using a federated architecture. The dataset for this development, comprising the outputs of a Global Navigation Satellite System (GNSS) receiver, an Inertial Measurement Unit (IMU) and a monocular camera is generated in a high-fidelity simulation framework. The simulation framework is built around Spirent’s GSS7000 simulator, software tools from Spirent (SimGEN and SimSENSOR) and OKTAL-SE (Sim3D), where the realism for the vision sensor data generation is provided by a photorealistic environment generated using the AirSim software with the Unreal Engine aid. To verify and validate the fusion framework a hardware in the loop (HIL) set-up has been implemented using the Pixhawk controller. The results obtained demonstrate that the presented HIL set-up is the essential component of a more robust navigation solution development framework, providing resilience under conditions of GNSS outages. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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2762 KiB

Open AccessProceeding Paper

Performance Improvement Provided by Global Navigation Satellite System Foresight Geospatial Augmentation in Deep Urban Environments

by Esther Anyaegbu, Paul Hansen and Bo Peng

Eng. Proc. 2023, 54(1), 58; https://doi.org/10.3390/ENC2023-15444 - 29 Oct 2023

Viewed by 318

Abstract

Global navigation satellite systems (GNSSs) are an integral part of global positioning. However, because GNSS performance is impacted by signal obscuration and the presence of multipath in urban and deep urban environments, it is not accurate, reliable, and widely available enough to be [...] Read more.

Global navigation satellite systems (GNSSs) are an integral part of global positioning. However, because GNSS performance is impacted by signal obscuration and the presence of multipath in urban and deep urban environments, it is not accurate, reliable, and widely available enough to be a standalone system in all environments. This creates two problems: (1) the GNSS user does not know when or where GNSS performance may be degraded and (2) the GNSS user has limited ability to mitigate these issues. No mitigation strategy exists to improve the availability of GNSSs themselves. Inertial measurement units (IMUs) and sensor fusion provide other costly methods to improve positioning performance, but most systems still rely on GNSSs for absolute position. Spirent’s GNSS Foresight service aims to solve both issues. As a cloud-based solution, GNSS Foresight provides satellite and signal information, and this can be employed to support the decision-making strategy and calculations in the GNSS receiver to improve its positioning solution performance, integrity, and reliability. In this paper, GNSS Foresight is introduced, and a performance evaluation of GNSS Foresight in dense urban areas is presented. Using the data collected from two urban areas in North America, we evaluated GNSS Foresight and compared the performance of GNSS positioning solutions with and without Foresight-aided data. The comparison results show the observed improvements in GNSS receiver operation. Foresight can also be used to develop measurement engine performance enhancements in the acquisition of new satellites and the tracking/re-acquisition of current satellites using line-of-sight (LOS) satellite information. In the positional computation process, Foresight enables receivers to prioritize LOS signals over degraded non-line-of-sight (NLOS) signals, hence significantly reducing positioning errors and outperforming conventional GNSS positioning, particularly in difficult urban environments. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1034 KiB

Open AccessProceeding Paper

Hardware in the Loop Laboratory Test Systems for Medium Frequency R-Mode Receivers

by Lars Grundhöfer, Filippo Giacomo Rizzi, Niklas Hehenkamp and Stefan Gewies

Eng. Proc. 2023, 54(1), 59; https://doi.org/10.3390/ENC2023-15464 - 29 Oct 2023

Viewed by 242

Abstract

Terrestrial radio navigation systems are an important data source for increasing the integrity of position, navigation, and timing information and for strengthening the immunity to the spoofing and jamming of satellite-based systems. A possible solution for maritime use is the medium frequency R-Mode. [...] Read more.

Terrestrial radio navigation systems are an important data source for increasing the integrity of position, navigation, and timing information and for strengthening the immunity to the spoofing and jamming of satellite-based systems. A possible solution for maritime use is the medium frequency R-Mode. Here, the first real results were presented in the Baltic Sea within the R-Mode Baltic project. For the development of receivers and future signal evolution of R-Mode, there is a great need to provide simulated signals to the receiver hardware. For our laboratory work, we developed different hardware in the loop test systems which enable the simulation of each of the three components and the entire medium frequency R-Mode signal. With this setup, we are able to conduct reproducible tests of the R-Mode receiver’s ranging and positioning performance without the necessity of field tests. Furthermore, the impact of R-Mode signal modifications can be initially analyzed without the need of an implementation in the real-world test bed. Firstly, we describe the usage of arbitrary wave generators that can be used to replay received or simulated signals. Due to their wide distribution in electronic laboratories, there are cost-efficient ways to build up test capabilities. For this work, we tested the Tektronix AFG 3022 and the Rigol DG1032. For further tests, we utilize software-defined radios that are capable of streaming continuous signals. We utilize the ETTUS N210 to directly output the simulated signals. Additionally, we test the LimeSDR with an external down-converter. To generate these signals, we utilize software packages that were created to support the development of the digital signal processing. This approach allows us to test our receiver with a continuous integration from pure software to hardware in the loop test. A comprehensive summary gives an overview of the pros and cons for the different suggested systems. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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8540 KiB

Open AccessProceeding Paper

Satellite Navigation Signal Interference Detection and Machine Learning-Based Classification Techniques towards Product Implementation

by Jelle Rijnsdorp, Annemarie van Zwol and Merle Snijders

Eng. Proc. 2023, 54(1), 60; https://doi.org/10.3390/ENC2023-15449 - 29 Oct 2023

Viewed by 395

Abstract

Many critical applications highly depend on Global Navigation Satellite Systems (GNSS) for precise and continuously available positioning and timing information. To warn a GNSS user that the signals are compromised, real-time interference detection is required. Additionally, real-time classification of the interference signal allows [...] Read more.

Many critical applications highly depend on Global Navigation Satellite Systems (GNSS) for precise and continuously available positioning and timing information. To warn a GNSS user that the signals are compromised, real-time interference detection is required. Additionally, real-time classification of the interference signal allows the user to select the most effective mitigation methods for the encountered disturbance. A compact proof of concept has been built using commercial off-the-shelf (COTS) components to analyse the jamming detection and classification techniques. It continuously monitors GNSS frequency bands and generates warnings to the user when interference is detected and classified. Various signal spectrum analyses, consisting of kurtosis and power spectral density (PSD) calculations, as well as a machine learning model, are used to detect and classify anomalies in the incoming signals. The system has been tested by making use of a COTS GNSS signal simulator. The simulator is used to generate the upper L-band GNSS signals and different types of interferences. Successful detection and classification is demonstrated, even for interference power levels that do not degrade the performance of a commercial reference receiver. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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1495 KiB

Open AccessProceeding Paper

Antiference: New Concept for Evolutive Mitigation of RFI to GNSS

by Shahrzad Afroozeh, Vincent Bejach, Uros Bokan, André Bos, Bastiaan Ober and Sascha Bartl

Eng. Proc. 2023, 54(1), 61; https://doi.org/10.3390/ENC2023-15451 - 29 Oct 2023

Viewed by 219

Abstract

The past decade has shown a growing awareness of the dangers of intentional interference (especially jamming and spoofing) with GNSS signals. The Antiference project uses reconfigurable digital signal processing methods in the detection, classification, and mitigation of interference by employing machine learning techniques. [...] Read more.

The past decade has shown a growing awareness of the dangers of intentional interference (especially jamming and spoofing) with GNSS signals. The Antiference project uses reconfigurable digital signal processing methods in the detection, classification, and mitigation of interference by employing machine learning techniques. The ML-based jamming classifier uses distinctive features of spectrograms for the differentiation of various jamming attacks. A residual neural net is used to map the spectrograms to the different jamming types. It relies on a fingerprinting architecture. Fingerprints summarize the characteristics of all the incoming signals, which are stored in and matched to a database of previously encountered interference types. To validate the implemented functionalities, a developed test-bed runs test scenarios and benchmarks the results against two state-of-the-art COTS receivers with interference mitigation capabilities. Full article

(This article belongs to the Proceedings of European Navigation Conference ENC 2023)

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