Friederike Fohlmeister, L. Kurz, M. Kriegel, S. Plass
This paper summarizes the design and setup of DLR’s GNSS scintillation recording device which is installed aboard “Polarstern”, the German research icebreaker. From September 2019 to September 2020 the icebreaker drifts with the ice shelf through the Arctic Sea. The paper is concluded by an overview of the data which was recorded until beginning of January 2020.
{"title":"One Year GNSS Ionospheric Scintillation Recording in the Arctic aboard Icebreaker “Polarstern”","authors":"Friederike Fohlmeister, L. Kurz, M. Kriegel, S. Plass","doi":"10.33012/2020.17183","DOIUrl":"https://doi.org/10.33012/2020.17183","url":null,"abstract":"This paper summarizes the design and setup of DLR’s GNSS scintillation recording device which is installed aboard “Polarstern”, the German research icebreaker. From September 2019 to September 2020 the icebreaker drifts with the ice shelf through the Arctic Sea. The paper is concluded by an overview of the data which was recorded until beginning of January 2020.","PeriodicalId":315030,"journal":{"name":"Proceedings of the 2020 International Technical Meeting of The Institute of Navigation","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134347458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Atomic Timekeeping as a Hobby","authors":"Tom van Baak","doi":"10.33012/2020.17204","DOIUrl":"https://doi.org/10.33012/2020.17204","url":null,"abstract":"","PeriodicalId":315030,"journal":{"name":"Proceedings of the 2020 International Technical Meeting of The Institute of Navigation","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126890747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Auryn P. Soderini, P. Thevenon, C. Macabiau, Laurent Borgagni, J. Fischer
The long-term evolution (LTE) reference signals, such as the primary synchronization signal (PSS), secondary synchronization signal (SSS) and cell-specific reference signal (CRS), have been studied for navigation. The signal structure including its influence on signal tracking has been previously discussed. However, there are non-reference signals such as the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid automatic repeat request (HARQ) indicator channel (PHICH) and physical downlink control channel (PDCCH) that can also be used for navigation. To the authors’ knowledge, pseudorange estimates with LTE physical channels have been almost not considered in the literature. This paper makes two contributions. First, the LTE physical channels properties which are relevant for signal tracking are discussed. Second, the expected tracking performance with LTE physical channels used in a standalone fashion are evaluated.
{"title":"Pseudorange Measurements with LTE Physical Channels","authors":"Auryn P. Soderini, P. Thevenon, C. Macabiau, Laurent Borgagni, J. Fischer","doi":"10.33012/2020.17180","DOIUrl":"https://doi.org/10.33012/2020.17180","url":null,"abstract":"The long-term evolution (LTE) reference signals, such as the primary synchronization signal (PSS), secondary synchronization signal (SSS) and cell-specific reference signal (CRS), have been studied for navigation. The signal structure including its influence on signal tracking has been previously discussed. However, there are non-reference signals such as the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid automatic repeat request (HARQ) indicator channel (PHICH) and physical downlink control channel (PDCCH) that can also be used for navigation. To the authors’ knowledge, pseudorange estimates with LTE physical channels have been almost not considered in the literature. This paper makes two contributions. First, the LTE physical channels properties which are relevant for signal tracking are discussed. Second, the expected tracking performance with LTE physical channels used in a standalone fashion are evaluated.","PeriodicalId":315030,"journal":{"name":"Proceedings of the 2020 International Technical Meeting of The Institute of Navigation","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127817212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Garcia‐Pena, C. Macabiau, O. Julien, M. Mabilleau, P. Durel
GNSS L5/E5a interference environment is dominated by DME/TACAN and JTIDS/MIDS pulses causing a degradation of the effective C/N0 observed by the receiver. A time-domain blanker is implemented to mitigate their impact. RTCA DO-292 proposes a model to compute the C/N0 degradation of the received useful signal by the increase of the noise PSD. This paper focuses on the impact of DME/TACAN RFI signals. Simulated results as well as predicted results are presented for US and Europe scenarios. The predicted results are calculated from an updated C/N0 degradation formula with respect to RTCA DO292 proposed formula. The impact of GNSS receiver RFFE filter bandwidth and blanker threshold are evaluated.
{"title":"Impact of DME/TACAN on GNSS L5/E5a Receiver","authors":"A. Garcia‐Pena, C. Macabiau, O. Julien, M. Mabilleau, P. Durel","doi":"10.33012/2020.17207","DOIUrl":"https://doi.org/10.33012/2020.17207","url":null,"abstract":"GNSS L5/E5a interference environment is dominated by DME/TACAN and JTIDS/MIDS pulses causing a degradation of the effective C/N0 observed by the receiver. A time-domain blanker is implemented to mitigate their impact. RTCA DO-292 proposes a model to compute the C/N0 degradation of the received useful signal by the increase of the noise PSD. This paper focuses on the impact of DME/TACAN RFI signals. Simulated results as well as predicted results are presented for US and Europe scenarios. The predicted results are calculated from an updated C/N0 degradation formula with respect to RTCA DO292 proposed formula. The impact of GNSS receiver RFFE filter bandwidth and blanker threshold are evaluated.","PeriodicalId":315030,"journal":{"name":"Proceedings of the 2020 International Technical Meeting of The Institute of Navigation","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124586405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ikhlas Selmi, P. Thevenon, C. Macabiau, O. Julien, M. Mabilleau
After the observed Evil Wave Form (EWF) event in 1993, an ICAO Threat Model (TM) and Threat Space (TS) are proposed for GPS L1 C/A signal to characterize those distortions [1]. Then, a Signal Quality Monitoring (SQM) algorithm is designed to protect civil aviation users from the potential risk of these signal anomalies. Under the development of new ICAO standards for Galileo, the EWF for Galileo signals have to be characterized in order to design suitable SQM algorithm to protect aviation user when using those new signals in operation. Based on the ICAO TM and the TS adapted to Galileo signals, a SQM design needs to be defined for Galileo E1 and E5 signals in Dual Frequency Multi-Constellation (DFMC) systems. This paper focuses on the SQM design and compliance test when considering a very large EWF TS including the Galileo TS. The hazardous EWF cases that need to be detected by the SQM are those characterized by a differential bias larger than the Maximum tolerable Error (MERR) within the tested TS. The EWF differential bias is defined as the worst bias observed when the anomaly occurs on the satellite after (called rising scenario) or before (called risen scenario) it is being monitored by the SBAS reference stations. The required missed detection and false alarm probabilities for the tested TS are evaluated based on the called time-varying MERR methodology [2] and SBAS parameters. The paper proposes a SQM and code pseudorange jump monitor (CCI) that is compliant with the SBAS integrity and continuity requirements considering the TS for Galileo signals.
{"title":"Signal Quality Monitoring Algorithm Applied to Galileo Signals for Large Evil Waveform Threat Space","authors":"Ikhlas Selmi, P. Thevenon, C. Macabiau, O. Julien, M. Mabilleau","doi":"10.33012/2020.17149","DOIUrl":"https://doi.org/10.33012/2020.17149","url":null,"abstract":"After the observed Evil Wave Form (EWF) event in 1993, an ICAO Threat Model (TM) and Threat Space (TS) are proposed for GPS L1 C/A signal to characterize those distortions [1]. Then, a Signal Quality Monitoring (SQM) algorithm is designed to protect civil aviation users from the potential risk of these signal anomalies. Under the development of new ICAO standards for Galileo, the EWF for Galileo signals have to be characterized in order to design suitable SQM algorithm to protect aviation user when using those new signals in operation. Based on the ICAO TM and the TS adapted to Galileo signals, a SQM design needs to be defined for Galileo E1 and E5 signals in Dual Frequency Multi-Constellation (DFMC) systems. This paper focuses on the SQM design and compliance test when considering a very large EWF TS including the Galileo TS. The hazardous EWF cases that need to be detected by the SQM are those characterized by a differential bias larger than the Maximum tolerable Error (MERR) within the tested TS. The EWF differential bias is defined as the worst bias observed when the anomaly occurs on the satellite after (called rising scenario) or before (called risen scenario) it is being monitored by the SBAS reference stations. The required missed detection and false alarm probabilities for the tested TS are evaluated based on the called time-varying MERR methodology [2] and SBAS parameters. The paper proposes a SQM and code pseudorange jump monitor (CCI) that is compliant with the SBAS integrity and continuity requirements considering the TS for Galileo signals.","PeriodicalId":315030,"journal":{"name":"Proceedings of the 2020 International Technical Meeting of The Institute of Navigation","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122781130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nowadays, a precise position and attitude information is significantly required for specific application scenarios like autonomous driving of vehicles or precise mobile mapping. The GNSS carrier phase measurements appear compulsory to satisfy the sub-meter or even centimeter level need for this kind of requirement. In this paper, we firstly use a method includes an array of receivers with known geometry to enhance the performance of the RTK in different environments. Taking advantages of the attitude information and known geometry of the array of receivers, we are able to improve some internal steps of precise position computation. Different scenarios are conducted including varying the distance between the 2 antennas of the receiver array, the satellite geometry and the amplitude of the noise measurement to validate the influence of the using of an array of receivers. The simulations results show that our multi-receiver RTK system is more robust to noise and degraded satellite geometry, in terms of ambiguity fixing rate, and get a better position accuracy under same conditions when comparing with the single receiver system.
{"title":"Improvement of RTK Performances Using an Array of Receivers with Known Geometry","authors":"Xiao Hu, P. Thevenon, C. Macabiau","doi":"10.33012/2020.17154","DOIUrl":"https://doi.org/10.33012/2020.17154","url":null,"abstract":"Nowadays, a precise position and attitude information is significantly required for specific application scenarios like autonomous driving of vehicles or precise mobile mapping. The GNSS carrier phase measurements appear compulsory to satisfy the sub-meter or even centimeter level need for this kind of requirement. In this paper, we firstly use a method includes an array of receivers with known geometry to enhance the performance of the RTK in different environments. Taking advantages of the attitude information and known geometry of the array of receivers, we are able to improve some internal steps of precise position computation. Different scenarios are conducted including varying the distance between the 2 antennas of the receiver array, the satellite geometry and the amplitude of the noise measurement to validate the influence of the using of an array of receivers. The simulations results show that our multi-receiver RTK system is more robust to noise and degraded satellite geometry, in terms of ambiguity fixing rate, and get a better position accuracy under same conditions when comparing with the single receiver system.","PeriodicalId":315030,"journal":{"name":"Proceedings of the 2020 International Technical Meeting of The Institute of Navigation","volume":"755 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126943488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Ugazio, Brian C. Peters, Kevin Croissant, Gregory Jenkins, Ryan McKnight, F. Graas
INTRODUCTION A core aspect of Global Navigation Satellite Systems (GNSSs) is the time scale they use to operate. Since they use independent time scales, inter-system time-offsets are one of the most significant biases to be taken into account in a multi-constellation solution, and in the framework of interoperability. In [1] a performance analysis is presented considering GPS, Galileo, GLONASS and BeiDou, showing inter-system time-offsets on the order of 10 to 100 ns. While a multi-system solution enables more satellites in view and possibly a better Geometric Dilution of Precision (GDOP), it must be taken into account that any additional constellation involves an additional bias. So, if a single-constellation solution involves four unknowns, including the user’s spatial coordinates and the receiver time offset, a multi-system solution exploiting measurements from N_GNSS constellations involves 4 + N_GNSS^-1 unknows, where the additional N_GNSS^_1 unknows are the inter-system time offsets to be estimated. This means that in order to get an improvement with respect to a single-system solution, at least two satellites from any additional constellation must be in view. In general, on-Earth users have enough satellites in view to get an improvement in GDOP thanks to a multi-GNSS solution. However, this is not always true when the user is in a low-visibility environment. In those cases, a multi-GNSS solution would ideally be beneficial, providing more satellites in view. On the other hand, the inter-system time-biases may constitute the bottle neck, and actually make the solution unavailable. Different approaches have been proposed to overcome this issue. The ICG-IGS Joint Trial Project (IGS-IGMA), led by the International Committee on GNSS (ICG) and the International GNSS Service (IGS), includes as long term objectives to “make all performance standard entries for each GNSS openly available” and to “provide a multi-GNSS service performance standard” [2]. The IGS Multi-GNSS Experiment (MGEX) [3-5] has, among its objectives to provide multi-GNSS products, exploit the IGS monitoring station network, and estimate biases and provide standards. In [6], different methods for the estimation of the inter-system biases are evaluated; the measurement model is constrained assuming the inter-system offset as constant over short time intervals, enabling the solution with only four satellites from mixed constellations. Another possible approach is to provide the users with the inter-system time-offset estimates. [7] describes the implementation of the GPS to Galileo Time Offset (GGTO), which is currently broadcast as part of the Galileo message, with an accuracy of 20 ns (95%, initial service target) [8]. However, as analyzed in [6], [9] and detailed in [10], different receivers have different impacts on the inter-system bias, being on the order of 20 ns and therefore comparable with GGTO [11]. This means that in order to exploit the broadcast estimate, inter-s
{"title":"GNSS Inter-system Time-Offset Estimates and Impact on High Altitude SSV","authors":"S. Ugazio, Brian C. Peters, Kevin Croissant, Gregory Jenkins, Ryan McKnight, F. Graas","doi":"10.33012/2020.17146","DOIUrl":"https://doi.org/10.33012/2020.17146","url":null,"abstract":"INTRODUCTION A core aspect of Global Navigation Satellite Systems (GNSSs) is the time scale they use to operate. Since they use independent time scales, inter-system time-offsets are one of the most significant biases to be taken into account in a multi-constellation solution, and in the framework of interoperability. In [1] a performance analysis is presented considering GPS, Galileo, GLONASS and BeiDou, showing inter-system time-offsets on the order of 10 to 100 ns. \u0000\u0000While a multi-system solution enables more satellites in view and possibly a better Geometric Dilution of Precision (GDOP), it must be taken into account that any additional constellation involves an additional bias. So, if a single-constellation solution involves four unknowns, including the user’s spatial coordinates and the receiver time offset, a multi-system solution exploiting measurements from N_GNSS constellations involves 4 + N_GNSS^-1 unknows, where the additional N_GNSS^_1 unknows are the inter-system time offsets to be estimated. This means that in order to get an improvement with respect to a single-system solution, at least two satellites from any additional constellation must be in view. \u0000\u0000In general, on-Earth users have enough satellites in view to get an improvement in GDOP thanks to a multi-GNSS solution. However, this is not always true when the user is in a low-visibility environment. In those cases, a multi-GNSS solution would ideally be beneficial, providing more satellites in view. On the other hand, the inter-system time-biases may constitute the bottle neck, and actually make the solution unavailable. Different approaches have been proposed to overcome this issue. The ICG-IGS Joint Trial Project (IGS-IGMA), led by the International Committee on GNSS (ICG) and the International GNSS Service (IGS), includes as long term objectives to “make all performance standard entries for each GNSS openly available” and to “provide a multi-GNSS service performance standard” [2]. The IGS Multi-GNSS Experiment (MGEX) [3-5] has, among its objectives to provide multi-GNSS products, exploit the IGS monitoring station network, and estimate biases and provide standards. In [6], different methods for the estimation of the inter-system biases are evaluated; the measurement model is constrained assuming the inter-system offset as constant over short time intervals, enabling the solution with only four satellites from mixed constellations. Another possible approach is to provide the users with the inter-system time-offset estimates. [7] describes the implementation of the GPS to Galileo Time Offset (GGTO), which is currently broadcast as part of the Galileo message, with an accuracy of 20 ns (95%, initial service target) [8]. However, as analyzed in [6], [9] and detailed in [10], different receivers have different impacts on the inter-system bias, being on the order of 20 ns and therefore comparable with GGTO [11]. This means that in order to exploit the broadcast estimate, inter-s","PeriodicalId":315030,"journal":{"name":"Proceedings of the 2020 International Technical Meeting of The Institute of Navigation","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128810252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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