A. Garcia‐Pena, O. Julien, C. Macabiau, M. Mabilleau, P. Durel
In the Global Navigation Satellite System (GNSS) L5/E5a interference environment, RTCA DO-292 proposes a model to compute the C/N0 degradation due to the presence of interference signals, such as Distance Measuring Equipment/TACtical Air Navigation (DME/TACAN), Joint Tactical Information Distribution System/Multifunctional Information Distribution System (JTIDS/MIDS), etc., and due to the application of a temporal blanker to mitigate their impact. The C/N0 degradation is modeled as a function of the blanker duty cycle, bdc, and the equivalent noise-level contribution of the non-blanked interference, RI. However, in RTCA DO-292, the computation of these two terms has a reduced accuracy since a general statistical model of signal pulse collisions and an overbounded flat post-blanker pulsed interference signal Power Spectrum Density (PSD) are assumed. In this paper, the limitations of the applied pulse collisions mathematical model are commented, and the use of true post-blanker pulsed interference signal PSD is introduced through the application of the spectral separation coefficient. As a result, more accurate new formulas for RI and C/N0 degradation are derived. The new formulas are verified through simulations for DME/TACAN signals.
{"title":"GNSS degradation model in presence of continuous wave and pulsed interference","authors":"A. Garcia‐Pena, O. Julien, C. Macabiau, M. Mabilleau, P. Durel","doi":"10.1002/NAVI.405","DOIUrl":"https://doi.org/10.1002/NAVI.405","url":null,"abstract":"In the Global Navigation Satellite System (GNSS) L5/E5a interference environment, RTCA DO-292 proposes a model to compute the C/N0 degradation due to the presence of interference signals, such as Distance Measuring Equipment/TACtical Air Navigation (DME/TACAN), Joint Tactical Information Distribution System/Multifunctional Information Distribution System (JTIDS/MIDS), etc., and due to the application of a temporal blanker to mitigate their impact. The C/N0 degradation is modeled as a function of the blanker duty cycle, bdc, and the equivalent noise-level contribution of the non-blanked interference, RI. However, in RTCA DO-292, the computation of these two terms has a reduced accuracy since a general statistical model of signal pulse collisions and an overbounded flat post-blanker pulsed interference signal Power Spectrum Density (PSD) are assumed. In this paper, the limitations of the applied pulse collisions mathematical model are commented, and the use of true post-blanker pulsed interference signal PSD is introduced through the application of the spectral separation coefficient. As a result, more accurate new formulas for RI and C/N0 degradation are derived. The new formulas are verified through simulations for DME/TACAN signals.","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"68 1","pages":"75-91"},"PeriodicalIF":0.0,"publicationDate":"2021-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/NAVI.405","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49654700","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}
Pub Date : 2021-01-01DOI: 10.18949/JINNAVI.216.0_65
Ishida Yoriko, Maehata Kohei
{"title":"Actual Situation and Future Prospective of Gender Equality and W L B in the Maritime Shipping Industry ：Deconstructing and Improving the Organizational Culture and Ideology","authors":"Ishida Yoriko, Maehata Kohei","doi":"10.18949/JINNAVI.216.0_65","DOIUrl":"https://doi.org/10.18949/JINNAVI.216.0_65","url":null,"abstract":"","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"216 1","pages":"65-76"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68079848","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}
Pub Date : 2021-01-01DOI: 10.18949/JINNAVI.216.0_44
和昌 中野
{"title":"JRCS Digital Innovation LABの紹介","authors":"和昌 中野","doi":"10.18949/JINNAVI.216.0_44","DOIUrl":"https://doi.org/10.18949/JINNAVI.216.0_44","url":null,"abstract":"","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"216 1","pages":"44-45"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68080078","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. Svatoň, F. Vejražka, P. Kubalík, Jan H. Schmidt, Jaroslav Borecký
This paper presents a new modified Single Block Zero-Padding (mSBZP) Partial Correlation Method (PCM) Parallel Code Search (PCS) algorithm for effective acquisition of weak GNSS tiered signal using coherent processing of its secondary code (SC) component. Two problems are discussed: acquisition of primary codes with a longer period using FFT blocks of limited length, and the utilization of PCS in the presence of SC bit transition. The PCM and SC bit transition forms parasitic fragments in the Cross-Ambiguity-Function (CAF) to devaluate signal detection performance. A novel analysis of this mechanism and its impact is presented. A novel mSBZP-PCM-PCS algorithm is proposed, which does not degrade the CAF. Then, the algorithm is combined with SC bit transition removal schema and sequential search to construct an estimator for weak tiered signal acquisition. The performance of the method is demonstrated by analysis and computer simulation using Galileo E1C and GPS L1C-P signals.
{"title":"Novel partial correlation method algorithm for acquisition of GNSS tiered signals","authors":"J. Svatoň, F. Vejražka, P. Kubalík, Jan H. Schmidt, Jaroslav Borecký","doi":"10.1002/NAVI.390","DOIUrl":"https://doi.org/10.1002/NAVI.390","url":null,"abstract":"This paper presents a new modified Single Block Zero-Padding (mSBZP) Partial Correlation Method (PCM) Parallel Code Search (PCS) algorithm for effective acquisition of weak GNSS tiered signal using coherent processing of its secondary code (SC) component. Two problems are discussed: acquisition of primary codes with a longer period using FFT blocks of limited length, and the utilization of PCS in the presence of SC bit transition.\u0000\u0000The PCM and SC bit transition forms parasitic fragments in the Cross-Ambiguity-Function (CAF) to devaluate signal detection performance. A novel analysis of this mechanism and its impact is presented. A novel mSBZP-PCM-PCS algorithm is proposed, which does not degrade the CAF. Then, the algorithm is combined with SC bit transition removal schema and sequential search to construct an estimator for weak tiered signal acquisition.\u0000\u0000The performance of the method is demonstrated by analysis and computer simulation using Galileo E1C and GPS L1C-P signals.","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"67 1","pages":"745-762"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/NAVI.390","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45751622","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. Rino, Brian Breitsch, Y. Morton, Dongyang Xu, C. Carrano
Precise measurements of signal phase are essential for Global Navigation Satellite System (GNSS) position estimates. However, propagation through the earth's ionosphere imposes frequency-dependent phase errors. The frequency dependence is exploited to correct phase errors proportional to total electron content (TEC) divided by frequency. Scintillation causes additional stochastic errors, which can become the largest phase error contribution. Both geometry-free (GFCs) and ionosphere-free (IFCs) frequency combinations are subject to such uncorrectable but generally small phase scintillation errors. A recent published study compared GPS TEC estimates derived from nominally identical L1-L2 and L1-L5 GFCs. The TEC errors establish an upper bound on uncorrelated single-frequency scintillation error contributions. The measured TEC errors were verified with phase-screen simulations. However, a known but largely overlooked phase unwrapping error affects the extraction of signal phase from phase-screen complex signal realizations. This paper demonstrates a procedure for detecting and correcting phase-unwrapping errors and discusses their ramifications.
{"title":"GNSS signal phase, TEC, and phase unwrapping errors","authors":"C. Rino, Brian Breitsch, Y. Morton, Dongyang Xu, C. Carrano","doi":"10.1002/navi.396","DOIUrl":"https://doi.org/10.1002/navi.396","url":null,"abstract":"Precise measurements of signal phase are essential for Global Navigation Satellite System (GNSS) position estimates. However, propagation through the earth's ionosphere imposes frequency-dependent phase errors. The frequency dependence is exploited to correct phase errors proportional to total electron content (TEC) divided by frequency. Scintillation causes additional stochastic errors, which can become the largest phase error contribution. Both geometry-free (GFCs) and ionosphere-free (IFCs) frequency combinations are subject to such uncorrectable but generally small phase scintillation errors. A recent published study compared GPS TEC estimates derived from nominally identical L1-L2 and L1-L5 GFCs. The TEC errors establish an upper bound on uncorrelated single-frequency scintillation error contributions. The measured TEC errors were verified with phase-screen simulations. However, a known but largely overlooked phase unwrapping error affects the extraction of signal phase from phase-screen complex signal realizations. This paper demonstrates a procedure for detecting and correcting phase-unwrapping errors and discusses their ramifications.","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"67 1","pages":"865-873"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/navi.396","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45316901","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}
High spatio-temporal variability of atmospheric water vapor affects microwave signals of Global Navigation Satellite Systems (GNSS) and Interferometric Synthetic Aperture Radar (InSAR). A better knowledge of the distribution of water vapor improves both GNSS- and InSAR-derived data products. In this work, we present a collocation framework to combine and retrieve zenith and (relative) slant tropospheric delays. GNSS and InSAR meteorological products are combined aiming at a better retrieval of the atmospheric water vapor. We investigate the combination approach with synthetic and real data acquired in the Alpine region of Switzerland. Based on a closed-loop validation with simulated delays, a few mm accuracy is achieved for the GNSS-InSAR combination in terms of retrieved ZTDs. Furthermore, when real delays are collocated, the combination results are more congruent with InSAR computed products. This research is a contribution to improve the spatio-temporal mapping of tropospheric delays by combining GNSS-derived and InSAR-derived delays.
{"title":"A collocation framework to retrieve tropospheric delays from a combination of GNSS and InSAR","authors":"Endrit Shehaj, K. Wilgan, O. Frey, A. Geiger","doi":"10.1002/navi.398","DOIUrl":"https://doi.org/10.1002/navi.398","url":null,"abstract":"High spatio-temporal variability of atmospheric water vapor affects microwave signals of Global Navigation Satellite Systems (GNSS) and Interferometric Synthetic Aperture Radar (InSAR). A better knowledge of the distribution of water vapor improves both GNSS- and InSAR-derived data products. In this work, we present a collocation framework to combine and retrieve zenith and (relative) slant tropospheric delays. GNSS and InSAR meteorological products are combined aiming at a better retrieval of the atmospheric water vapor. We investigate the combination approach with synthetic and real data acquired in the Alpine region of Switzerland. Based on a closed-loop validation with simulated delays, a few mm accuracy is achieved for the GNSS-InSAR combination in terms of retrieved ZTDs. Furthermore, when real delays are collocated, the combination results are more congruent with InSAR computed products. This research is a contribution to improve the spatio-temporal mapping of tropospheric delays by combining GNSS-derived and InSAR-derived delays.","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"67 1","pages":"823-842"},"PeriodicalIF":0.0,"publicationDate":"2020-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/navi.398","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41741084","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 future of deep space exploration depends upon technological advancement towards improving spacecraft's autonomy and versatility. This study aims to examine the feasibility of autonomous orbit determination using advanced accelerometer measurements. The objective of this research is to ascertain specific sensor requirements to meet pre-defined mission navigation error budgets. Traditional inertial navigation (dead reckoning and external aiding) is not considered. Instead, measurements from pairs of advanced, highly sensitive accelerometers (e.g., cold atom accelerometers) are used onboard to determine gravity field gradients, which are then correlated to onboard gravity maps and used to determine orbital information. Linear Covariance Theory helps to efficiently conduct an error budget analysis of the system. This error budget analysis helps to determine the effect of specific error sources in the sensor measurements, thereby providing information to rank and compare relevant sensor parameters and determine an optimal sensor configuration for a given space mission. The procedure is repeated to evaluate different accelerometer configurations and sensor parameters.
{"title":"Sensitivity Analysis of Precision Inertial Sensor‐based Navigation System (SAPIENS)","authors":"Rachit Bhatia, D. Geller","doi":"10.1002/navi.397","DOIUrl":"https://doi.org/10.1002/navi.397","url":null,"abstract":"The future of deep space exploration depends upon technological advancement towards improving spacecraft's autonomy and versatility. This study aims to examine the feasibility of autonomous orbit determination using advanced accelerometer measurements. The objective of this research is to ascertain specific sensor requirements to meet pre-defined mission navigation error budgets. Traditional inertial navigation (dead reckoning and external aiding) is not considered. Instead, measurements from pairs of advanced, highly sensitive accelerometers (e.g., cold atom accelerometers) are used onboard to determine gravity field gradients, which are then correlated to onboard gravity maps and used to determine orbital information. Linear Covariance Theory helps to efficiently conduct an error budget analysis of the system. This error budget analysis helps to determine the effect of specific error sources in the sensor measurements, thereby providing information to rank and compare relevant sensor parameters and determine an optimal sensor configuration for a given space mission. The procedure is repeated to evaluate different accelerometer configurations and sensor parameters.","PeriodicalId":30601,"journal":{"name":"Annual of Navigation","volume":"67 1","pages":"795-822"},"PeriodicalIF":0.0,"publicationDate":"2020-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/navi.397","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41351063","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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