Liu Cheng, Gao Weiguang, Tianxi Liu, Wang Dun, Zheng Yao, Yang Gao, Nie Xin, Wei Wang, Liao Dongjun, Weixing Zhang, Dongxiao Wang, Yongnan Rao
Precise point positioning (PPP) service is of great significance for BDS. The design and implementation of the service are presented. The PPP-B2b signal of the service is constructed, which is efficient multiplexed with other signal components, and achieves compatibility between two service phases. A customized message format that can augment all visible satellites of four core constellations in mainland China is proposed. The high-gain, 64-ary, low-density parity check (LDPC) coding is used, which facilitates the integrated design of the receivers. A signal quality test has revealed that the S-curve bias (SCB) of PPP-B2b does not exceed 0.0165 ns and the coherence between the code and the carrier of the signal is only 0.137 degrees. A performance evaluation has indicated that at its current stage, the positioning accuracy in the horizontal and vertical directions is better than 0.15 m and 0.3 m, respectively, and the convergence time does not exceed 800 s.
{"title":"Design and implementation of a BDS precise point positioning service","authors":"Liu Cheng, Gao Weiguang, Tianxi Liu, Wang Dun, Zheng Yao, Yang Gao, Nie Xin, Wei Wang, Liao Dongjun, Weixing Zhang, Dongxiao Wang, Yongnan Rao","doi":"10.1002/navi.392","DOIUrl":"https://doi.org/10.1002/navi.392","url":null,"abstract":"Precise point positioning (PPP) service is of great significance for BDS. The design and implementation of the service are presented. The PPP-B2b signal of the service is constructed, which is efficient multiplexed with other signal components, and achieves compatibility between two service phases. A customized message format that can augment all visible satellites of four core constellations in mainland China is proposed. The high-gain, 64-ary, low-density parity check (LDPC) coding is used, which facilitates the integrated design of the receivers. A signal quality test has revealed that the S-curve bias (SCB) of PPP-B2b does not exceed 0.0165 ns and the coherence between the code and the carrier of the signal is only 0.137 degrees. A performance evaluation has indicated that at its current stage, the positioning accuracy in the horizontal and vertical directions is better than 0.15 m and 0.3 m, respectively, and the convergence time does not exceed 800 s.","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"67 1","pages":"875-891"},"PeriodicalIF":0.0,"publicationDate":"2020-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/navi.392","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46193399","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":"GNSS interference mitigation: A measurement and position domain assessment","authors":"D. Borio, C. Gioia","doi":"10.1002/NAVI.391","DOIUrl":"https://doi.org/10.1002/NAVI.391","url":null,"abstract":"","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/NAVI.391","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43284960","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}
This paper develops novel covariance and square-root factor formulations of a consider-neglect Kalman filter for navigation applications. The proposed filter partitions system parameters into three distinct categories: those to be estimated by the filter, those whose contribution to the system are considered without being explicitly estimated, and those with sufficiently low effect on the system such that their contribution can be neglected altogether. Discussion on appropriate selection of parameters to be considered and neglected is provided with specific attention given to descent-to-landing navigation. Monte Carlo simulations and analysis are performed to assess the performance of the developed square-root consider-neglect filter in a descent-to-landing navigation scenario.
{"title":"Modular framework for implementation and analysis of recursive filters with considered and neglected parameters","authors":"Kyle J. DeMars, Kari C. Ward","doi":"10.1002/NAVI.388","DOIUrl":"https://doi.org/10.1002/NAVI.388","url":null,"abstract":"This paper develops novel covariance and square-root factor formulations of a consider-neglect Kalman filter for navigation applications. The proposed filter partitions system parameters into three distinct categories: those to be estimated by the filter, those whose contribution to the system are considered without being explicitly estimated, and those with sufficiently low effect on the system such that their contribution can be neglected altogether. Discussion on appropriate selection of parameters to be considered and neglected is provided with specific attention given to descent-to-landing navigation. Monte Carlo simulations and analysis are performed to assess the performance of the developed square-root consider-neglect filter in a descent-to-landing navigation scenario.","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"67 1","pages":"843-863"},"PeriodicalIF":0.0,"publicationDate":"2020-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/NAVI.388","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45558982","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}
Pedestrian navigation with handheld sensors is still particularly complex. Pedestrian Dead Reckoning method is generally used, but the estimation of the walking direction remains problematic because the device's pointing direction does not always correspond to the walking direction. To overcome this difficulty, it is possible to use gait modeling based approaches. But, these methods suffer from sporadic erroneous estimates and their accumulation over time. The HEAD (smootH Estimation of wAlking Direction) filter uses WAISS and MAGYQ angular estimates as observations to correct the walking direction and to obtain more robust and smooth results. TDCP updates are applied to constrain the walking direction estimation error while pseudo-ranges directly update the position. HEAD is tested by 5 subjects over 21 indoor/outdoor acquisitions (between 720 m and 1.3 km). A 54% improvement is achieved thanks to the fusion in texting mode. The median obtained angular error is 5.5 degrees in texting mode and 12 degrees in pocket mode.
{"title":"HEAD: smootH Estimation of wAlking Direction with a handheld device embedding inertial, GNSS, and magnetometer sensors","authors":"Johan Perul, Valérie Renaudin","doi":"10.1002/NAVI.389","DOIUrl":"https://doi.org/10.1002/NAVI.389","url":null,"abstract":"Pedestrian navigation with handheld sensors is still particularly complex. Pedestrian Dead Reckoning method is generally used, but the estimation of the walking direction remains problematic because the device's pointing direction does not always correspond to the walking direction. To overcome this difficulty, it is possible to use gait modeling based approaches. But, these methods suffer from sporadic erroneous estimates and their accumulation over time. The HEAD (smootH Estimation of wAlking Direction) filter uses WAISS and MAGYQ angular estimates as observations to correct the walking direction and to obtain more robust and smooth results. TDCP updates are applied to constrain the walking direction estimation error while pseudo-ranges directly update the position. HEAD is tested by 5 subjects over 21 indoor/outdoor acquisitions (between 720 m and 1.3 km). A 54% improvement is achieved thanks to the fusion in texting mode. The median obtained angular error is 5.5 degrees in texting mode and 12 degrees in pocket mode.","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"67 1","pages":"713-726"},"PeriodicalIF":0.0,"publicationDate":"2020-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/NAVI.389","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43385055","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 former Galileo Commercial Service (CS) will provide a High Accuracy Service (HAS) and a Commercial Authentication Service (CAS). The first will disseminate free Precise Point Positioning (PPP) corrections through the E6-B signal whereas the second will provide authentication capabilities through the E6-C pilot component that will be encrypted. For this reason, improved processing strategies for data-only processing need to be investigated. The combined use of Kalman filtering and noncoherent integrations is analyzed in this work. A Software Defined Radio (SDR) receiver has been developed and used for the analysis. Different scenarios were considered including simulated data with decreasing Carrier-to-Noise Power Spectral Density Ratio (C/N0) levels and live static and dynamic data collected under harsh environments. It emerges that the use of Kalman filtering with extended noncoherent integrations is an effective approach to improve the performance of data-only processing.
{"title":"Kalman filtering with noncoherent integrations for Galileo E6‐B tracking","authors":"M. Susi, D. Borio","doi":"10.1002/navi.380","DOIUrl":"https://doi.org/10.1002/navi.380","url":null,"abstract":"The former Galileo Commercial Service (CS) will provide a High Accuracy Service (HAS) and a Commercial Authentication Service (CAS). The first will disseminate free Precise Point Positioning (PPP) corrections through the E6-B signal whereas the second will provide authentication capabilities through the E6-C pilot component that will be encrypted. For this reason, improved processing strategies for data-only processing need to be investigated. The combined use of Kalman filtering and noncoherent integrations is analyzed in this work. A Software Defined Radio (SDR) receiver has been developed and used for the analysis. Different scenarios were considered including simulated data with decreasing Carrier-to-Noise Power Spectral Density Ratio (C/N0) levels and live static and dynamic data collected under harsh environments. It emerges that the use of Kalman filtering with extended noncoherent integrations is an effective approach to improve the performance of data-only processing.","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"67 1","pages":"601-618"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/navi.380","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42201292","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. Lo, Yu‐Hsuan Chen, P. Enge, W. Pelgrum, Kuangmin Li, George Weida, Achim Soelter
Distance measuring equipment (DME) has been a cornerstone of aviation navigation for the last 70 years. While GNSS is taking an increasingly important role in civil aviation, DME can still play an important role in a robust aviation infrastructure in the foreseeable future. Advanced concepts have been developed to improve DME performance and capabilities. One concept is a DME-based pseudolite that position modulates existing DME pulse pairs. It is interoperable with DME operations and can be generated using the currently fielded DME transponders with an applique. This concept is suitable as a robust alternative to GNSS for aviation navigation or timing. The paper examines the performance of DME pseudolite implemented via an applique on a DME transponder. The paper examines the synchronization and data performance of the DME pseudolite signal in the air and on the ground. The paper compares the actual performance to theoretical results.
{"title":"Flight test of a pseudo‐ranging signal compatible with existing distance measuring equipment (DME) ground stations","authors":"S. Lo, Yu‐Hsuan Chen, P. Enge, W. Pelgrum, Kuangmin Li, George Weida, Achim Soelter","doi":"10.1002/navi.376","DOIUrl":"https://doi.org/10.1002/navi.376","url":null,"abstract":"Distance measuring equipment (DME) has been a cornerstone of aviation navigation for the last 70 years. While GNSS is taking an increasingly important role in civil aviation, DME can still play an important role in a robust aviation infrastructure in the foreseeable future. Advanced concepts have been developed to improve DME performance and capabilities. One concept is a DME-based pseudolite that position modulates existing DME pulse pairs. It is interoperable with DME operations and can be generated using the currently fielded DME transponders with an applique. This concept is suitable as a robust alternative to GNSS for aviation navigation or timing. The paper examines the performance of DME pseudolite implemented via an applique on a DME transponder. The paper examines the synchronization and data performance of the DME pseudolite signal in the air and on the ground. The paper compares the actual performance to theoretical results.","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"67 1","pages":"567-582"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/navi.376","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42384044","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 in-motion alignment for the underwater strapdown inertial navigation system is still a challenging problem due to various disturbances in the underwater environment. In this paper, a novel in-motion alignment method, based on the Lie group representation, is developed. In this method, the process model is rewritten using the Lie group of the constant attitude matrix between two inertial frames as the state. An exact linear measurement model is constructed by analyzing the effect of the sensor errors in calculating the velocity vector. Next, the state-dependent Lie group filter is designed basing on accurate derivation expressions for the covariance matrices of state-dependent noises. The simulation and experiment results demonstrate that the proposed method can achieve better alignment accuracy and time than the existing method. The accuracy improves by 70% with the quaternion Kalman filter.
{"title":"A novel in‐motion alignment method for underwater SINS using a state‐dependent Lie group filter","authors":"Fu-jun Pei, Hao Xu, Ning Jiang, Desen Zhu","doi":"10.1002/navi.387","DOIUrl":"https://doi.org/10.1002/navi.387","url":null,"abstract":"The in-motion alignment for the underwater strapdown inertial navigation system is still a challenging problem due to various disturbances in the underwater environment. In this paper, a novel in-motion alignment method, based on the Lie group representation, is developed. In this method, the process model is rewritten using the Lie group of the constant attitude matrix between two inertial frames as the state. An exact linear measurement model is constructed by analyzing the effect of the sensor errors in calculating the velocity vector. Next, the state-dependent Lie group filter is designed basing on accurate derivation expressions for the covariance matrices of state-dependent noises. The simulation and experiment results demonstrate that the proposed method can achieve better alignment accuracy and time than the existing method. The accuracy improves by 70% with the quaternion Kalman filter.","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"67 1","pages":"451-470"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/navi.387","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44777376","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}
This research investigates the mutual interference between a GNSS signal refracted through the atmosphere and the same signal reflected from the surface below. For low-altitude occultations, the reflected signal can be present as multipath when tracking the direct signal. This poses a problem when making remote sensing measurements using GNSS-RO or GNSS-R techniques. Here, this issue is addressed in the context of GNSS data collected by a mountaintop receiver on the Hawaiian island of Maui. First, an elevation-angle threshold, below which the reflected signal can be present as multipath on the direct signal, is calculated for the mountaintop geometry. Next, the first steps are taken to mitigate the mutual interference between the direct and reflected signals. A frequency-domain filtering approach and a time-domain smoothing approach are applied to the signal intensity in an effort to separate the multipath contribution and the direct signal contribution.
{"title":"Characterization and mitigation of interference between GNSS radio occultation and reflectometry signals for low‐altitude occultations","authors":"Ian Collett, Y. Morton, Yang Wang, Brian Breitsch","doi":"10.1002/navi.375","DOIUrl":"https://doi.org/10.1002/navi.375","url":null,"abstract":"This research investigates the mutual interference between a GNSS signal refracted through the atmosphere and the same signal reflected from the surface below. For low-altitude occultations, the reflected signal can be present as multipath when tracking the direct signal. This poses a problem when making remote sensing measurements using GNSS-RO or GNSS-R techniques. Here, this issue is addressed in the context of GNSS data collected by a mountaintop receiver on the Hawaiian island of Maui. First, an elevation-angle threshold, below which the reflected signal can be present as multipath on the direct signal, is calculated for the mountaintop geometry. Next, the first steps are taken to mitigate the mutual interference between the direct and reflected signals. A frequency-domain filtering approach and a time-domain smoothing approach are applied to the signal intensity in an effort to separate the multipath contribution and the direct signal contribution.","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"67 1","pages":"537-546"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/navi.375","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43013542","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}
We propose a Simultaneous Localization and Mapping (SLAM)-based Integrity Monitoring (IM) algorithm using GPS and fish-eye camera to compute the protection levels while accounting for multiple faults in GPS and vision. We perform graph optimization using GPS pseudoranges, pixel intensities, vehicle dynamics, and satellite ephemeris to simultaneously localize the vehicle, GPS satellites, and key image pixels in the world frame. We estimate the fault mode vector by analyzing the temporal correlation across pseudorange residuals and spatial correlation across pixel intensity residuals. To isolate the vision faults, we develop a superpixel-based piecewise random sample consensus. For the estimated fault mode, we compute the protection levels by performing worst-case failure slope analysis on the batch realization of linearized Graph-SLAM formulation. We perform real-world experiments in an alleyway in Stanford, California and a semi-urban area in Champaign, Illinois. We demonstrate higher localization accuracy and tighter protection levels as compared to GPS-only SLAM-based IM.
{"title":"Integrity monitoring of Graph‐SLAM using GPS and fish‐eye camera","authors":"Sriramya Bhamidipati, G. Gao","doi":"10.1002/navi.381","DOIUrl":"https://doi.org/10.1002/navi.381","url":null,"abstract":"We propose a Simultaneous Localization and Mapping (SLAM)-based Integrity Monitoring (IM) algorithm using GPS and fish-eye camera to compute the protection levels while accounting for multiple faults in GPS and vision. We perform graph optimization using GPS pseudoranges, pixel intensities, vehicle dynamics, and satellite ephemeris to simultaneously localize the vehicle, GPS satellites, and key image pixels in the world frame. We estimate the fault mode vector by analyzing the temporal correlation across pseudorange residuals and spatial correlation across pixel intensity residuals. To isolate the vision faults, we develop a superpixel-based piecewise random sample consensus. For the estimated fault mode, we compute the protection levels by performing worst-case failure slope analysis on the batch realization of linearized Graph-SLAM formulation. We perform real-world experiments in an alleyway in Stanford, California and a semi-urban area in Champaign, Illinois. We demonstrate higher localization accuracy and tighter protection levels as compared to GPS-only SLAM-based IM.","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"67 1","pages":"583-600"},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/navi.381","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42379206","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}
J. Jurado, J. Raquet, Christine M. Schubert Kabban, Jonathon S. Gipson
All-source navigation has become increasingly relevant over the past decade with the development of viable alternative sensor technologies. However, as the number and type of sensors informing a system increases, so does the probability of corrupting the system with sensor modeling errors, signal interference, and undetected faults. Though the latter of these has been extensively researched, the majority of existing approaches have constrained faults to biases and designed algorithms centered around the assumption of simultaneously redundant, synchronous sensors with valid measurement models, none of which are guaranteed for all-source systems. As part of an overall all-source assured or resilient navigation objective, this research contributes a fault- and sensor-agnostic fault detection and exclusion method that can provide the user with performance guarantees without constraining the statistical distribution of the fault. The proposed method is compared against normalized solution separation approaches using Monte-Carlo simulations in a 2D non-GPS navigation problem.
{"title":"Residual‐based multi‐filter methodology for all‐source fault detection, exclusion, and performance monitoring","authors":"J. Jurado, J. Raquet, Christine M. Schubert Kabban, Jonathon S. Gipson","doi":"10.1002/navi.384","DOIUrl":"https://doi.org/10.1002/navi.384","url":null,"abstract":"All-source navigation has become increasingly relevant over the past decade with the development of viable alternative sensor technologies. However, as the number and type of sensors informing a system increases, so does the probability of corrupting the system with sensor modeling errors, signal interference, and undetected faults. Though the latter of these has been extensively researched, the majority of existing approaches have constrained faults to biases and designed algorithms centered around the assumption of simultaneously redundant, synchronous sensors with valid measurement models, none of which are guaranteed for all-source systems. As part of an overall all-source assured or resilient navigation objective, this research contributes a fault- and sensor-agnostic fault detection and exclusion method that can provide the user with performance guarantees without constraining the statistical distribution of the fault. The proposed method is compared against normalized solution separation approaches using Monte-Carlo simulations in a 2D non-GPS navigation problem.","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"146 3","pages":"493-510"},"PeriodicalIF":0.0,"publicationDate":"2020-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/navi.384","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41255722","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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