In celestial navigation the altitude (elevation) angles to multiple celestial bodies are measured; these measurements are then used to compute the position of the user on the surface of the Earth. Methods described in the literature include the classical “altitude-intercept” algorithm as well as direct and iterative least-squares solutions for over determined situations. While it seems rather obvious that the user should select bright stars scattered across the sky, there appears to be no established results on the level of performance that is achievable based upon the number of stars sighted nor how the “best” set of stars might be selected from those visible. This paper addresses both of these issues by examining the performance of celestial navigation noting its similarity to the performance of GNSS systems; specifically, modern results on GDOP for GNSS are adapted to this classical celestial navigation problem.
{"title":"Rethinking Star Selection in Celestial Navigation","authors":"P. Swaszek, R. Hartnett, K. Seals","doi":"10.33012/2019.16678","DOIUrl":"https://doi.org/10.33012/2019.16678","url":null,"abstract":"In celestial navigation the altitude (elevation) angles to multiple celestial bodies are measured; these measurements are then used to compute the position of the user on the surface of the Earth. Methods described in the literature include the classical “altitude-intercept” algorithm as well as direct and iterative least-squares solutions for over determined situations. While it seems rather obvious that the user should select bright stars scattered across the sky, there appears to be no established results on the level of performance that is achievable based upon the number of stars sighted nor how the “best” set of stars might be selected from those visible. This paper addresses both of these issues by examining the performance of celestial navigation noting its similarity to the performance of GNSS systems; specifically, modern results on GDOP for GNSS are adapted to this classical celestial navigation problem.","PeriodicalId":332769,"journal":{"name":"Proceedings of the 2019 International Technical Meeting of The Institute of Navigation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125469902","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":"GPS and InSAR Inversion for Coseismic Deformation Field and Slip Distribution of the Ms7.0 Jiuzhaigou Earthquake","authors":"Huixia Li, Wenhao Wu, Hang Guo, R. Langley","doi":"10.33012/2019.16718","DOIUrl":"https://doi.org/10.33012/2019.16718","url":null,"abstract":"","PeriodicalId":332769,"journal":{"name":"Proceedings of the 2019 International Technical Meeting of The Institute of Navigation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126621813","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}
The Wide Area Augmentation System (WAAS) [1] has found that the ranging signals from its geostationary (GEO) satellites can significantly improve the availability of vertical guidance, particularly in Alaska and at times when not all GPS satellites are operational. However, WAAS has also observed that the GEO ranging sources can be affected by errors that are bias-like in their behavior [2] [3] [4] [5] [6] [7]. Such errors do not change values randomly but may persist with a particular sign and magnitude for many hours or longer. Some of these bias errors commonly affect our reference receivers and may thus be difficult to observe and bound in real time. Others are readily observable but not necessarily easy to eliminate as they may impact user receivers differently. One such error results from incoherence between the code and the carrier signals. Unlike GPS, the GEO signals are generated on the ground and have to traverse the ionosphere both on the way up from the ground uplink station (GUS) to the GEO and then on the way down from the GEO to the user. The GUS electronics may not always be able to keep the two components perfectly aligned. This results in a code-carrier incoherency (CCI) that creates a varying error for users with different smoothing times. A user whose carrier smoothing filter has converged will see a different effect from a user who has not smoothed their code measurements with carrier data [2]. When WAAS generates a confidence bound on the ranging accuracy of the GEO satellites, it must account for all different users and for every error source. Unfortunately, the protection level equations used by WAAS do not support the inclusion of bias terms or terms to account for different smoothing times [8]. Therefore, WAAS must conduct special analyses to bound these biases. This paper describes the analysis WAAS performs to ensure that the UDRE it broadcasts for each GEO safely bounds all users for all possible bias errors. This analysis accounts for other fault modes that may also be present, but not yet detected by the WAAS integrity monitors. Versions of GEO bias analyses have existed since before WAAS was commissioned in 2003. The analysis has been updated and significantly improved since those early more conservative approaches. WAAS is in the midst of replacing all three of its GEOs and will briefly have four operational ranging GEOs in the summer of 2019. Pseudorange bias terms can lead to much bigger user position errors when there are more such terms that may all align. This WAAS GEO bias analysis has been recently updated and each new GEO has been carefully examined to ensure the continued safe operation of GEO ranging. This paper describes this analysis and demonstrates the safety and performance of the new WAAS GEOs Error Bounding Analysis Because the broadcast sigmas (User Differential Range Error (UDRE) and Grid Ionospheric Vertical Error (GIVE)) are larger than the actual overbounds, constant biases up to a certain ma
{"title":"Safety Analysis of Ranging Biases on the WAAS GEOs","authors":"T. Walter, J. Blanch, E. Altshuler","doi":"10.33012/2019.16679","DOIUrl":"https://doi.org/10.33012/2019.16679","url":null,"abstract":"The Wide Area Augmentation System (WAAS) [1] has found that the ranging signals from its geostationary (GEO) satellites can significantly improve the availability of vertical guidance, particularly in Alaska and at times when not all GPS satellites are operational. However, WAAS has also observed that the GEO ranging sources can be affected by errors that are bias-like in their behavior [2] [3] [4] [5] [6] [7]. Such errors do not change values randomly but may persist with a particular sign and magnitude for many hours or longer. Some of these bias errors commonly affect our reference receivers and may thus be difficult to observe and bound in real time. Others are readily observable but not necessarily easy to eliminate as they may impact user receivers differently. One such error results from incoherence between the code and the carrier signals. Unlike GPS, the GEO signals are generated on the ground and have to traverse the ionosphere both on the way up from the ground uplink station (GUS) to the GEO and then on the way down from the GEO to the user. The GUS electronics may not always be able to keep the two components perfectly aligned. This results in a code-carrier incoherency (CCI) that creates a varying error for users with different smoothing times. A user whose carrier smoothing filter has converged will see a different effect from a user who has not smoothed their code measurements with carrier data [2]. When WAAS generates a confidence bound on the ranging accuracy of the GEO satellites, it must account for all different users and for every error source. Unfortunately, the protection level equations used by WAAS do not support the inclusion of bias terms or terms to account for different smoothing times [8]. Therefore, WAAS must conduct special analyses to bound these biases. This paper describes the analysis WAAS performs to ensure that the UDRE it broadcasts for each GEO safely bounds all users for all possible bias errors. This analysis accounts for other fault modes that may also be present, but not yet detected by the WAAS integrity monitors. Versions of GEO bias analyses have existed since before WAAS was commissioned in 2003. The analysis has been updated and significantly improved since those early more conservative approaches. WAAS is in the midst of replacing all three of its GEOs and will briefly have four operational ranging GEOs in the summer of 2019. Pseudorange bias terms can lead to much bigger user position errors when there are more such terms that may all align. This WAAS GEO bias analysis has been recently updated and each new GEO has been carefully examined to ensure the continued safe operation of GEO ranging. This paper describes this analysis and demonstrates the safety and performance of the new WAAS GEOs Error Bounding Analysis Because the broadcast sigmas (User Differential Range Error (UDRE) and Grid Ionospheric Vertical Error (GIVE)) are larger than the actual overbounds, constant biases up to a certain ma","PeriodicalId":332769,"journal":{"name":"Proceedings of the 2019 International Technical Meeting of The Institute of Navigation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130304228","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}
Eustachio Roberto Matera, A. Garcia‐Pena, O. Julien, C. Milner, Bertrand Ekambi
An increasing number of new applications require an accurate positioning even in urban environments; however, in such environments, especially in urban canyons, GNSS positioning is challenged to meet the applications’ demanded accuracy and reliability. In fact, in order to obtain an optimal and reliable position estimate using GNSS, it is necessary to have an accurate model of the pseudorange and pseudorange rate error terms’ distributions. This work focuses thus its attention on the statistical characterization of the pseudorange measurements’ multipath error component by proposing a methodology to obtain such characterization: isolation of the multipath error component from the use of a reference station, to eliminate ionospheric error terms, and from a filtering process, to eliminate the receiver clock bias. The proposed methodology has been adapted to include dual constellation measurementsin the L1 band, GPS L1 C/A and Galileo E1 OS signal measurements, as an evolution to the previous method presented by the authors in [1]. Moreover, in order to obtain a reliable classification of the signal reception conditions, Lion-of-Sight (LOS) and Non LOS (NLOS), which will allow a finer characterization of the multipath error component, this work introduces the use of an upward looking camera with a wide Field-of-View (FOV), a fisheye camera: the satellites are projected on the pictures taken by the camera allowing to observe which satellites are obstructed by the scenario obstacles (buildings, trees, etc). The proposed methodology is applied to real measurements obtained from a data campaign conducted in Toulouse urban area with a U-Blox receiver with its antenna and a fisheye camera mounted on the roof of a car. The pseudorange measurements are classified by the signal ??/??0 and by the elevation angle between the satellites and the receiver, which are common signal characteristics influencing the multipath error component impact on the pseudorange measurement. Additionally, the performance assessment of each parameter in terms of signal reception conditions classification between LOS and NLOS has determined the upper hand of the ??/??0 parameter.
{"title":"Characterization of Line-of-sight and Non-line-of-sight Pseudorange Multipath Errors in Urban Environment for GPS and Galileo","authors":"Eustachio Roberto Matera, A. Garcia‐Pena, O. Julien, C. Milner, Bertrand Ekambi","doi":"10.33012/2019.16687","DOIUrl":"https://doi.org/10.33012/2019.16687","url":null,"abstract":"An increasing number of new applications require an accurate positioning even in urban environments; however, in such environments, especially in urban canyons, GNSS positioning is challenged to meet the applications’ demanded accuracy and reliability. In fact, in order to obtain an optimal and reliable position estimate using GNSS, it is necessary to have an accurate model of the pseudorange and pseudorange rate error terms’ distributions. This work focuses thus its attention on the statistical characterization of the pseudorange measurements’ multipath error component by proposing a methodology to obtain such characterization: isolation of the multipath error component from the use of a reference station, to eliminate ionospheric error terms, and from a filtering process, to eliminate the receiver clock bias. The proposed methodology has been adapted to include dual constellation measurementsin the L1 band, GPS L1 C/A and Galileo E1 OS signal measurements, as an evolution to the previous method presented by the authors in [1]. Moreover, in order to obtain a reliable classification of the signal reception conditions, Lion-of-Sight (LOS) and Non LOS (NLOS), which will allow a finer characterization of the multipath error component, this work introduces the use of an upward looking camera with a wide Field-of-View (FOV), a fisheye camera: the satellites are projected on the pictures taken by the camera allowing to observe which satellites are obstructed by the scenario obstacles (buildings, trees, etc). The proposed methodology is applied to real measurements obtained from a data campaign conducted in Toulouse urban area with a U-Blox receiver with its antenna and a fisheye camera mounted on the roof of a car. The pseudorange measurements are classified by the signal ??/??0 and by the elevation angle between the satellites and the receiver, which are common signal characteristics influencing the multipath error component impact on the pseudorange measurement. Additionally, the performance assessment of each parameter in terms of signal reception conditions classification between LOS and NLOS has determined the upper hand of the ??/??0 parameter.","PeriodicalId":332769,"journal":{"name":"Proceedings of the 2019 International Technical Meeting of The Institute of Navigation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115782431","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}
In this paper, we develop a phase lock loop (PLL) tracking algorithm that allows continuous phase tracking through interference events. This concept is directly applicable to GPS receivers subject to wideband radio frequency interference. Kalman filters have been previously proposed as more flexible alternatives for carrier phase tracking than traditional PLLs using phase discriminators. However, the characteristics of the GPS signal lead to a hybrid estimation problem, requiring simultaneous estimation of the discrete navigation data bits and the continuous carrier phase. Interacting multiple model (IMM) algorithms are often used in such problems when systems are constrained to a finite set of dynamic or measurement models. In the case of GPS phase tracking, there are only two measurement models corresponding to the two choices of navigation data bits (+1 and -1). The estimated phase is obtained at each measurement timestep by combining the two modes’ estimation results using their respective likelihood functions. In this way, the IMM avoids generation of exponentially-growing candidate data bit sequences, which cannot be handled in real time GPS receivers. Batch simulation results are provided as a benchmark best case comparison for IMM phase tracking performance. Two choices of state variables are investigated for their feasibility and performance.
{"title":"IMM Methods for Carrier Phase Tracking and Navigation Data Bits Estimation Through Interference","authors":"Wengxiang Zhao, B. Pervan","doi":"10.33012/2019.16692","DOIUrl":"https://doi.org/10.33012/2019.16692","url":null,"abstract":"In this paper, we develop a phase lock loop (PLL) tracking algorithm that allows continuous phase tracking through interference events. This concept is directly applicable to GPS receivers subject to wideband radio frequency interference. Kalman filters have been previously proposed as more flexible alternatives for carrier phase tracking than traditional PLLs using phase discriminators. However, the characteristics of the GPS signal lead to a hybrid estimation problem, requiring simultaneous estimation of the discrete navigation data bits and the continuous carrier phase. Interacting multiple model (IMM) algorithms are often used in such problems when systems are constrained to a finite set of dynamic or measurement models. In the case of GPS phase tracking, there are only two measurement models corresponding to the two choices of navigation data bits (+1 and -1). The estimated phase is obtained at each measurement timestep by combining the two modes’ estimation results using their respective likelihood functions. In this way, the IMM avoids generation of exponentially-growing candidate data bit sequences, which cannot be handled in real time GPS receivers. Batch simulation results are provided as a benchmark best case comparison for IMM phase tracking performance. Two choices of state variables are investigated for their feasibility and performance.","PeriodicalId":332769,"journal":{"name":"Proceedings of the 2019 International Technical Meeting of The Institute of Navigation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132076360","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}
O. Kim, B. Shin, C. Kee, Chongwon Kim, Taikjin Lee, H. So, Gapjin Kim
{"title":"Single Transmitter based Precise Positioning System using Multiple Antenna: Experimental Tests","authors":"O. Kim, B. Shin, C. Kee, Chongwon Kim, Taikjin Lee, H. So, Gapjin Kim","doi":"10.33012/2019.16703","DOIUrl":"https://doi.org/10.33012/2019.16703","url":null,"abstract":"","PeriodicalId":332769,"journal":{"name":"Proceedings of the 2019 International Technical Meeting of The Institute of Navigation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130262870","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}
Hyeyeon Chang, M. Yoon, Jiyun Lee, S. Pullen, L. M. Pereira
{"title":"Assessment of Ionospheric Spatial Decorrelation for Daytime Operations of GBAS in the Brazilian Region","authors":"Hyeyeon Chang, M. Yoon, Jiyun Lee, S. Pullen, L. M. Pereira","doi":"10.33012/2019.16673","DOIUrl":"https://doi.org/10.33012/2019.16673","url":null,"abstract":"","PeriodicalId":332769,"journal":{"name":"Proceedings of the 2019 International Technical Meeting of The Institute of Navigation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125744553","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}
C. Enneking, F. Antreich, Manuel Appel, Andr L.F. de Almeida
{"title":"Pure Pilot Signals: How Short can we Choose GNSS Spreading Codes?","authors":"C. Enneking, F. Antreich, Manuel Appel, Andr L.F. de Almeida","doi":"10.33012/2019.16737","DOIUrl":"https://doi.org/10.33012/2019.16737","url":null,"abstract":"","PeriodicalId":332769,"journal":{"name":"Proceedings of the 2019 International Technical Meeting of The Institute of Navigation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128697978","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}
G. Johnson, Christopher Grayson, G. Dhungana, J. Delisle
{"title":"Field Data Collection to Validate the Usage of WAAS for Maritime Navigation in Canadian Waters","authors":"G. Johnson, Christopher Grayson, G. Dhungana, J. Delisle","doi":"10.33012/2019.16672","DOIUrl":"https://doi.org/10.33012/2019.16672","url":null,"abstract":"","PeriodicalId":332769,"journal":{"name":"Proceedings of the 2019 International Technical Meeting of The Institute of Navigation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132096642","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":"A Machine Learning Approach for Wi-Fi RTT Ranging","authors":"Nir Dvorecki, O. Bar-Shalom, L. Banin, Y. Amizur","doi":"10.33012/2019.16702","DOIUrl":"https://doi.org/10.33012/2019.16702","url":null,"abstract":"","PeriodicalId":332769,"journal":{"name":"Proceedings of the 2019 International Technical Meeting of The Institute of Navigation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123235946","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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