Proceedings of the Satellite Division's International Technical Meeting最新文献

{"title":"A Joint Vision of Infrastructure Strategy for Resilient Navigation in the Airspace","authors":"Okuary Osechas, Mitch Narins, Gerhard Berz, Lannie Herlihy, Sherman Lo","doi":"10.33012/2023.19445","DOIUrl":"https://doi.org/10.33012/2023.19445","url":null,"abstract":"Aeronautical navigation services supported by Global Navigation Satellite Systems (GNSS) have enabled a new generation of navigation procedures that offer improved precision and efficiency. GNSS supports a variety of procedures in various operating environments, like oceanic, enroute, terminal, approach and landing, as well as in airport environments; all of these procedures are conceived as overlays, meaning that they follow the same ground tracks as operations established before GNSS. A more recent type of service, like Required Navigation Performance (RNP), leverage GNSS augmentation services to support such airspace design flexibility, which will ultimately result in better efficiency. By supporting RNP, GNSS services can support new safe and efficient operational procedures that minimize Air Traffic Control (ATC) and pilot workload and support a higher degree of autonomy to aircraft. While the capabilities and use cases for GNSS services have expanded rapidly over the last two decades, the resilient, complementary means of navigation based on terrestrial radionavigation have not received the same levels of support, partly due to a lack of research and investment, but mainly because of the apparent continuing belief by some that with enough satellites, signals, and orbits, GNSS can become the sole means of deriving all position, navigation, and timing services. Efforts to “re-establish” the requirement for resilient and complementary PNT systems has once again become a priority, according to Appendix C of Resolution A41-8 (ICAO 2022). This is, in part, the result of a growing call for action and increasing numbers of interference events worldwide that have impacted the safety, security, and efficiency of air transportation.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135483693","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":"Study on the Benefits and Uses of OSNMA in Maritime Navigation","authors":"H. Llorca, M. López, E. Domínguez, T. Tisell, P. Scheidemann","doi":"10.33012/2023.19432","DOIUrl":"https://doi.org/10.33012/2023.19432","url":null,"abstract":"In the maritime field, the use of GNSS positioning systems is widespread for all types of applications, for both navigation and positioning purposes. The paper shows a study and a proposal for the use of Galileo Open Service Navigation Message Authentication (OSNMA) in the implementation of a new advanced maritime DFMC receiver. In recent years, the maritime community has begun to be aware that, in order to guarantee safety and security, it is also necessary to think that the vessels have to be resilient PNT and particularly to Cyberattacks. Multiple cases of spoofing attacks around the world have been reported in the last few years. Thanks to Galileo OSNMA in the receiver, the possibility of having a mechanism capable of mitigating some spoofing attacks has been included. In addition, OSNMA ICD allows different implementation approaches depending on the needs of the end user, focusing on ensuring different target security levels. Considering that spoofing attacks can generate false information in many ways, during tests carried out in the scope of the ASGARD project, the behaviour of OSNMA's functionality in the receiver has been studied through different types of attacks. Those different tested attacks are: meaconing attack (recording and replaying real GNSS SIS), spoofing replicating SIS without OSNMA information, spoofing with OSNMA information replicated as in SIS, spoofing of only some satellites in view (cross authentication) and spoofing with OSNMA information replicated as in SIS keeping the same IODs. Finally, different architecture options to implement OSNMA are assessed. ASGARD receiver has a scheme in which OSNMA is part of an external module. It permits to continue developing the functionalities of OSNMA, without accompanying them on the development of the receiver itself, to use that module in other receivers or autonomously and facilitates the module verification and validation tests.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135483701","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":"Integrity Assurance of LIRTK Using SS-RAIM Against Sensor Faults for UAV Applications","authors":"Noah Minchan Kim, Dongchan Min, Jiyun Lee","doi":"10.33012/2023.19457","DOIUrl":"https://doi.org/10.33012/2023.19457","url":null,"abstract":"This study proposes an integrity assurance architecture of Loosely-Coupled Kalman Filter-based Inertial Aiding for RTK (LIRTK) using Solution Separation based Receiver Autonomous Integrity Monitor (SS-RAIM). An integrity risk allocation tree of LIRTK is developed for each sensor fault hypothesis including the nominal hypothesis, single-satellite fault hypotheses, an IMU sensor fault hypothesis, and an incorrect fix fault hypothesis. Two P(CF) requirements for integrity risk and false alarm rate were defined in order to calculate the Vertical Protection Level (VPL) of the fixed solution. In order to improve the fixed rate by lowering the P(CF) requirement for false alarm rate, an ambiguity check process is newly proposed. In the ambiguity check process, the fixed ambiguities estimated under nominal and fault hypothesis are compared. After passing the ambiguity check process, this study found a new lower bound that relaxes the P(CF) requirement for false alarm rate and validated its mathematical proof. VPL simulations were performed for different Global Navigation Satellite System (GNSS) measurement noise levels and Inertial Measurement Unit (IMU) sensor grades. The simulation results demonstrated that the ambiguity check process significantly improved the fixed rate of LIRTK and exhibited a much higher value compared to single-epoch RTK.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135483794","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":"Multiple-Epoch Joint Localization and Synchronization in a 5G System","authors":"Lu Bai, Chao Sun, Andrew G. Dempster, Wenquan Feng, Yingzhe He","doi":"10.33012/2023.19252","DOIUrl":"https://doi.org/10.33012/2023.19252","url":null,"abstract":"Currently, the usage of GNSS signals for positioning in challenging propagation conditions like urban and indoor scenarios is still an open problem. The 5G network-based localization technique can help relieve the problem of lacking visible satellites in urban environments. Even it can work as an independent positioning means in the GNSS denied environments. However, in real applications, due to the limited cost, the 5G BSs cannot be equipped with expensive atomic clocks to keep time. Thus, the 5G interBS synchronization error cannot be ignored simply, which becomes a main limiting factor for 5G-based positioning techniques. To address the impact of 5G inter-BS synchronization error on positioning accuracy, this work proposes a multiple-epoch jointly localization and synchronization algorithm. We model the synchronization error of each BS as an unknown quantity to solve. This makes it possible to estimate the synchronization error of each BS precisely and finally get rid of the effect. Then we employ the correlation feature over multiple epochs to reduce the overall number of quantities to estimate. The Taylor series least square method is extended to fuse time of arrival (TOA) - angle of departure (AOD) measurements for positioning scheme. Further, the lower bound of positioning error of the proposed method, namely Cramer Rao Lower Bound (CRLB), is derived mathematically. Results show that the proposed method significantly reduce the positioning error compared with three baseline methods. It achieves joint localization and synchronization to improve the positioning accuracy in an imperfectly-synchronous 5G network.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135483907","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":"Characterization of Multi-GNSS Receiver Biases and their Temperature-Induced Variations in Low Earth Orbit","authors":"Zachary Arnett, Brian C. Peters, Ryan McKnight, Sabrina Ugazio","doi":"10.33012/2023.19360","DOIUrl":"https://doi.org/10.33012/2023.19360","url":null,"abstract":"In support of full interoperability between Global Navigation Satellite Systems (GNSSs) constellations, Bobcat-1, a 3-unit CubeSat, was deployed with the primary objective of evaluating the feasibility of estimating system-to-system time offsets (XYTOs) from low Earth orbit (LEO). Bobcat-1, developed by Ohio University, was deployed in November 2020 from the International Space Station (ISS) and deorbited in April 2021 after a successful 17-month mission. The maximum orbit altitude, after deployment, was about 440 km and was above 380 km for more than a year. At these altitudes, the ionospheric effect on GNSS measurements is lower than those experienced by terrestrial users but still present; the multi-GNSS receiver onboard Bobcat-1 provides multi-frequency measurements, enabling dual-frequency ionospheric corrections. However, ionospheric corrections are affected by receiver-specific inter-frequency bias (IFB) as well as by satellite differential code biases (DCBs). These biases need to be calibrated in order to form accurate XYTOs estimates. In addition, given the significant temperature variations experienced by Bobcat-1 in orbit, the effect of temperature on the receiver-specific IFB shall be taken into account. In this paper, the receiver-specific IFB calibration applied to Bobcat-1 is described and the in-lab IFB temperature calibration is validated over multiple in-orbit data collections, spanning a six-month time interval. Results shown in this analysis focus on Galileo E1C – E5b and GPS L2P(Y) (semi-codeless) – L5 IFB, with plans to expand to other GNSSs and frequency/signal combinations in future work. In order to separate the receiver-specific IFB from the ionospheric effect, a zero-total electron content (TEC) method is applied, resulting in residual errors whose upper bound can be defined using global TEC maps. More sophisticated TEC estimation techniques will enable more accurate IFB calibration in future work. As expected, the result shows that the temperature is the dominant effect on IFB variations, and it is seen that the calibration holds throughout data collected in-orbit.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"301 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135483915","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":"Tightly Integrated Smartphone GNSS and Visual odometry for Enhanced Urban Pedestrian Positioning","authors":"Yang Jiang, Yan Zhang, Zhitao Lyu, Shuai Guo, Yang Gao","doi":"10.33012/2023.19464","DOIUrl":"https://doi.org/10.33012/2023.19464","url":null,"abstract":"Precise smartphone-based positioning service is challenging in dense urban areas due to significant multipath effects in GNSS signals received by smartphone devices. The raw GNSS measurements will be contaminated by non-line-of-sight (NLOS) signals, severely deteriorating the smartphone positioning accuracy. Many methods have been proposed to mitigate the GNSS NLOS problem, including 3D mapping-aided GNSS, RAIM, and machine learning-based methods. But these methods have limitations such as the need for 3D city models or external devices, high false-alarm chances, and training processes. In this study, we have developed a new approach to improve smartphone positioning accuracy in dense urban areas by coupling the smartphone GNSS and camera sensors, which are already available in most smartphones. Wholly based on themselves, the proposed method tightly integrates GNSS pseudorange, carrier-phase and Doppler measurements, and a visual odometry (VO). The GNSS measurements undergo preprocessing, DD normal equations, and velocity estimations. The smartphone images are processed using a KLT optical flow method, where GNSS velocities are applied to estimate the coordinate rotation and scale between them based on a sliding-window least-squares scheme using Horn’s method. Importantly, a quad-tree-based outlier searching (QTOS) algorithm is applied to ensure the healthiness of estimation processes throughout the integration. The data from DD GNSS normal equations, GNSS velocities, and VO velocities are input to an FGO algorithm for final positioning estimations. A field test in the dense urban area of Calgary showed an improvement of 25% in horizontal accuracy and a reduction of velocity estimation error by 30%, where the chance of positioning outliers (> 30 m) is significantly reduced by 76%. Therefore, the proposed method provides an effective solution for precise smartphone positioning in dense urban areas without the need for external data sources or training.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135483918","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":"U.S. Department of Transportation (DOT) Global Positioning System (GPS) Interference Detection and Mitigation (IDM) Program","authors":"James S. Aviles, Karen L. Van Dyke","doi":"10.33012/2023.19248","DOIUrl":"https://doi.org/10.33012/2023.19248","url":null,"abstract":"Global Positioning System (GPS) Based Positioning, Navigation, and Timing (PNT) services support the United States transportation sector in safely transporting people and goods and enabling efficiencies resulting in benefits to national and economic security. GPS signals are broadcasted from a constellation of satellites orbiting in Medium Earth Orbit (MEO) and their signal strength at the user receiver is very low in signal power density magnitude and thus susceptible to unintentional and intentional signal disruption or manipulation from undesired sources. Two recent real-world events in the transportation sector highlight the impacts related to the susceptibility of these GPS signal disruptions and the constant need to improve the GPS Interference Detection and Mitigation (IDM) posture of the Department of Transportation with the goal to restore GPS based PNT services to the expected levels of availability and reliability. This IDM mission goal contributes to an overall resilient PNT services posture when GPS is quickly restored to the expected normal operating conditions. On January 21, 2022, the GPS signal-in-space around the city of Denver, CO was degraded by the presence of unwanted emissions south of the Denver International Airport1 . Numerous aircraft, train stations, emergency response communication towers and medical messaging services detected and experienced varying levels of GPS signal reception degradation for a period of approximately 33 hours until the unwanted emissions source was positively identified and shut down. On October 17, 2022, the GPS signal-in-space around the cities of Dallas and Fort Worth, TX was degraded by the presence of unwanted emissions southwest from the Dallas-Ft. Worth International Airport. Numerous aircraft in the terminal and air route airspace detected and experience GPS signal reception degradation for a period of approximately 44 hours. Ground infrastructure recordings of GPS signal degradation effects were absent during the active event affecting aircraft. The unwanted emissions source ceased without positively being identified.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135484039","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":"Receiver Bias Estimation Strategy in the Uncombined Triple-Frequency PPP-AR Model","authors":"Yichen Liu, Urs Hugentobler, Bingbing Duan, Nikolay Mikhaylov, Jeffrey Simon","doi":"10.33012/2023.19220","DOIUrl":"https://doi.org/10.33012/2023.19220","url":null,"abstract":"This study investigates the reparameterization of the uncombined triple-frequency PPP-AR model, mainly in terms of the receiver hardware bias estimation. We explore the impact of the number of estimated receiver bias parameters as a function of pseudorange noise, i.e., the trade-off between estimating too many bias parameters on cost of a high stochastic error posing a challenge on ambiguity resolution on one hand, and estimating too few bias parameters on cost of ignored inconsistencies on the other hand. We implemented 4 different bias estimation strategies and compared their performance in positioning and ambiguity resolution against each other in the presence of phase bias across various pseudorange noise levels. The results show that with accurately initialized reference ambiguities, for code noise levels below 0.3 meters, estimating four biases (one each for P3, L1, L2, L3 signals) outperforms other strategies, while for code noise levels exceeding 0.3 meters, estimating two biases is sufficient. Conversely, with inaccurately estimated reference ambiguities, estimating four biases constantly prevails across all code noise levels. In ideal conditions, i.e., bias-free scenario, however, estimating only one bias is the optimal choice. This research enables readers to get insight into bias estimation strategies in the uncombined triple-frequency PPP-AR model and their impact on positioning performance and ambiguity resolution across different code noise levels. The conclusions can act as a guideline supporting the user implementation of the optimum representation of hardware biases in the uncombined PPP-AR model.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135484051","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":"Internet-Based GNSS Signal Authentication","authors":"Dinesh Manandhar","doi":"10.33012/2023.19335","DOIUrl":"https://doi.org/10.33012/2023.19335","url":null,"abstract":"GNSS spoofing has become a serious issue for security, safety and automation-related applications. GNSS signal authentication is one of the effective methods to detect spoofing attacks. However, it may not be possible to implement signal authentication for existing signals such as GPS L1C/A. This paper describes how an internet-based GNSS signal authentication can be used to authenticate GPS, QZSS, Galileo, BeiDou, and SBAS signals. The advantage of an internet-based signal authentication system is that it can be implemented to existing GNSS signals signal without modifying anything at the space segment.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"301 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135484056","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":"Ephemeris Error Modeling in Opportunistic LEO Satellite Tracking with Pseudorange and Doppler Measurements","authors":"Samer Hayek, Joe Saroufim, Zaher M. Kassas","doi":"10.33012/2023.19453","DOIUrl":"https://doi.org/10.33012/2023.19453","url":null,"abstract":"A framework for tracking the ephemerides of low Earth orbit (LEO) satellites is presented. This framework considers a known receiver that tracks the position and velocity states of LEO satellites using pseudorange and Doppler measurements extracted opportunistically from the satellite’s signals. An analytical procedure to estimate the epoch time adjustment to reduce the simplified general perturbation 4 (SGP4)-propagated ephemerides errors is developed. An extended Kalman filter (EKF) is formulated in which the satellite’s argument of latitude is estimated in a closed-loop fashion using pseudorange or Doppler observables, and subsequently, an epoch time adjustment is approximated to reduce the satellite state initialization errors. A simulation study is conducted to validate the proposed framework for a Starlink satellite, where the initialization errors were reduced from 1,880 m when using SGP4 ephemerides to 356 m and 367 m when using pseudorange and Doppler measurements, respectively. Experimental results are presented where the ephemerides of an Orbcomm LEO satellite’s ephemerides are refined: the satellite’s position RMSE is reduced from over 7.1 km with SGP4 open-loop propagation to 242 m after the implementation of the proposed tracking framework. The tracked ephemerides are then used to localize a ground receiver, reducing the initial error from 2.67 km to 211 m. Using the SGP4 ephemerides was shown to increase the localization error to over 5.8 km.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135484059","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}