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

{"title":"Evaluation for BDSABS Ionospheric Grid Augmented by LEO Constellations","authors":"Xiaowei Lan, Hongwen Wang, Kun Fang, Yanbo Zhu, Zhipeng Wang","doi":"10.33012/2023.19177","DOIUrl":"https://doi.org/10.33012/2023.19177","url":null,"abstract":"The utilization of onboard GNSS receivers and the potential broadcasting of dual-frequency navigation signals for low earth orbit (LEO) satellites represent effective means for improving ionospheric modeling performance in the future. Regional ionospheric corrections can be provided by the single-frequency (SF) service of Satellite-Based Augmentation System (SBAS), and further improvement relies on effective utilizations of LEO-related observations, which travel only a portion of the ionosphere. In addressing this challenge, the ionosphere is simplified as multiple thin layers, and bottom-side LEO-related observations are compensated by the established topside ionospheric grid. Subsequently, observations from GPS and LEO are integrated, and the entire ionospheric grid of SBAS is estimated using Kriging. The performance improvement of the BeiDou SBAS (BDSBAS) ionospheric grid is evaluated in a simulated environment based on the NeQuick-2 model. The evaluation involves the GPS constellation and a LEO constellation comprising 192 satellites. The results indicate that the better performance is achieved when the bottom-side observations from LEO satellites are first compensated and then mapped to vertical delays. Accordingly, the optimal cut-off elevation angle for these observations is determined to be 15°. Under these conditions, the root mean square (RMS) of the vertical delay estimation errors for 117 ionospheric grid points (IGPs) decreases by an average of 16.47% throughout the day, with a maximum reduction of up to 38.39% compared to using only GPS observations. Additionally, it is observed that the inclusion of LEO-related observations has the most significant improvement on the southern edge IGPs of BDSBAS during periods of high solar activity throughout the day.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"440 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":"135483155","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":"Civil Aviation GNSS Interference Detection and Location Based on Genetic Algorithm Using ADS-B Data","authors":"Jinqi Li, Hongxia Wang, Zhiqiang Dan, Jiahao Xu, Zhipeng Wang, Yanbo Zhu","doi":"10.33012/2023.19392","DOIUrl":"https://doi.org/10.33012/2023.19392","url":null,"abstract":"According to the 41st session of the ICAO assembly, the very low strength of GNSS signals received from satellites makes GNSS vulnerable to radio frequency interference (RFI), and other undesirable disturbances, which poses a threat to aviation safety. In the field of civil aviation, the performance of GNSS is directly related to NACp, NUCp and other data widely used in Automatic Dependent Surveillance-Broadcast (ADS-B) system, where GNSS RFI can be reflected and located by their numerical changes. Interference detection and location based on ADS-B is a new way to solve GNSS RFI problem in civil aviation. Current researches focus on improving the performance of the algorithm, but there are few studies on the impact mechanism of GNSS RFI. This paper analyzes the influence of GNSS RFI on ADS-B data in principle, and provides theoretical support for algorithm, detects and locates RFI using genetic algorithm. The performance of the proposed detection and location algorithm is verified with the interference events in Chengdu, China in March 2021. It has made an attempt to the application of civil aviation surveillance and navigation fusion and to deal with GNSS RFI. This research provides theoretical reference and technical support for the detection and location of GNSS RFI in civil aviation.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"49 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":"135483183","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":"Navigation Performance of Low Lunar Orbit Satellites Using a Lunar Radio Navigation Satellite System","authors":"Serena Molli, Pasquale Tartaglia, Yoann Audet, Andrea Sesta, Michael Plumaris, Floor Melman, Richard Swinden, Pietro Giordano, Javier Ventura-Traveset","doi":"10.33012/2023.19370","DOIUrl":"https://doi.org/10.33012/2023.19370","url":null,"abstract":"Exploring the Moon is the next long-term target for space agencies in the coming decade depicted by the Moonlight program from the European Space Agency (ESA) which envisions the creation of a dedicated Lunar Communication and Navigation Service (LCNS) infrastructure. The purpose is to entail the installation of the human presence on the moon and support the long-term, sustainable, human presence on Earth’s natural satellite. The proposed LCNS constellation aims to support the lunar activities in the cislunar space, including landing, and surface operations. At an international level, ESA and NASA worked on the definition of an interoperability framework for communication and navigation services in cislunar space, leading to the definition of the LunaNet Interoperability Specification [NASA & ESA, 2022]. LunaNet defines multiple services, among which is a GNSS-like concept called Lunar Augmented Navigation Service (LANS). It is expected that multiple institutional and commercial programmes will adhere to LunaNet, allowing the creation of a network of nodes interoperable with each other. However, at least in the initial phase of systems deployment, the number of visible satellites for a cislunar user will be limited. This limitation can be mitigated by adopting sensor fusion techniques and other navigation techniques. This contribution investigates the achievable performances for a user in Low Lunar Orbit (LLO) using a constellation of satellites as an example of such a Lunar Communication and Navigation Service (LCNS). Realistic Orbit Determination and Time Synchronisation (ODTS) for the lunar constellation are simulated to be as representative as possible of the expected performances. The user navigation algorithm implements an accurate dynamical model by means of an extended Kalman filter, allowing it to compensate for the gaps in satellite visibility. Three types of low lunar orbits (LLO) (polar orbit, equatorial orbit and 45°inclined) are simulated to cover different scenarios. Position accuracy below 100m at 2sigma and a velocity determination accuracy below 1 m/s at 2sigma are achievable in real-time on-board.","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":"135483184","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 Navigation Signals Monitoring, Analysis and Recording Tool: Application to Real-Time Interference Detection and Classification","authors":"Iman Ebrahimi Mehr, Alex Minetto, Fabio Dovis","doi":"10.33012/2023.19391","DOIUrl":"https://doi.org/10.33012/2023.19391","url":null,"abstract":"Given the extensive dependency on Global Navigation Satellite Systems (GNSS) for several crucial applications, the disruption caused by intentional or unintentional Radio Frequency Interference (RFI) may dramatically affect reliability and poses potential threats to various operations dependent on such systems. Recently, these threats have increased, and their detection and mitigation are of utmost importance in the field. To this aim, this paper presents an architecture for real-time detection and classification of RFI affecting multi-band GNSS signals based on a machine learning method. This study proposes an architecture combining an actual GNSS monitoring station for recording GNSS signals (Navigation Signals Monitoring, Analysis, and Recording Tool (N-SMART) system) with a deep neural network approach to detect and classify different classes of interferences. The proposed approach enables continuous monitoring, recording, and prompt alerting of RFI occurrences in multi-band GNSS signals, by leveraging the flexibility of a Software Defined Radio and docker frameworks. The design and deployment aspects of the proposed architecture are discussed, and the performance of the classification algorithm is evaluated. The results of the experimental test campaign on real interfered GNSS signals showed an overall accuracy of 85% and they highlighted the potential for effective, real-time classification of RFIs in GNSS.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"82 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":"135483186","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":"Improving GNSS positioning correction using Deep Reinforcement Learning with Adaptive Reward Augmentation Method","authors":"Jianhao Tang, Zhenni Li, Rui Guo, Haoli Zhao, Qianming Wang, Ming Liu, Shengli Xie, Marios Polycarpou","doi":"10.33012/2023.19181","DOIUrl":"https://doi.org/10.33012/2023.19181","url":null,"abstract":"High-precision global navigation satellite system (GNSS) positioning for automatic driving in urban environments is an unsolved problem because of the influence of multipath effects. Recently, methods based on data-driven deep reinforcement learning (DRL) have been used to learn continual positioning-correction strategies without strict assumptions about model parameters, and are adaptable to nonstationary urban environments. However, these methods face two remaining challenges: 1) real-time data for training collected in nonstationary urban environments is inadequate because of issues such as response delay and signal interruption, which causes the performance degradation in DRL, 2) the existing methods use vehicle positions as the environment observations, ignoring the complex errors caused by multipath effects in urban environments. In this paper, we propose a novel DRL-based positioning-correction method with an adaptive reward augmentation method (ARAM), and use GNSS measurements instead of vehicle positions as the environment observations, for improving the GNSS positioning accuracy in nonstationary urban environments. To specify the accurate current state of the vehicle agent, we use the GNSS measurement observations, including the line-of-sight (LOS) vector and the pseudorange residual, to model complex environmental errors, and employ a long and short term memory (LSTM) module to learn the temporal aspects of the observations, which include the interference by multipath effects on the GNSS positioning in urban environments. To address the performance degradation caused by inadequate real-time training data, we employ ARAM to adaptively modify the matching of data between the source domain and target domain of the nonstationary urban environments, to leverage sufficient data from the source domain for training, and thus to improve the performance of DRL. Hence, based on ARAM and using the GNSS measurement observations, we construct an LSTM-based proximal policy optimization algorithm with ARAM (LSTMPPO-ARAM) to achieve an adaptive dynamic positioning-correction policy for nonstationary urban environments. The proposed method was evaluated using the Google smartphone decimeter challenge (GSDC) dataset and the Guangzhou GNSS measurement dataset, with the results demonstrating that our method can obtain about a 10% improvement in positioning performance over existing model-based methods and an 8% improvement over learning-based approaches.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"37 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":"135483278","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":"Weiss-Weinstein Bound of Frequency Error Considering von Mises Distribution as Prior for Very Weak GNSS Signals","authors":"Xin Zhang, Xingqun Zhan, Jihong Huang, Jiahui Liu, Yingchao Xiao","doi":"10.33012/2023.19240","DOIUrl":"https://doi.org/10.33012/2023.19240","url":null,"abstract":"Frequency tracking, usually serving as the pull-in stage for phase tracking, is a fundamental estimation problem in global navigation satellite system (GNSS) receivers. A lower bound tighter than existing bounds is developed for predicting frequency estimation errors. The traditional way of lower bounding the estimation errors using Cramér-Rao lower bound (CRB) does not take into account the prior information. Of all bounds in Bayesian framework, Weiss-Weinstein bound (WWB) stands out since it is free from regularity conditions imposed on a priori distribution. Therefore, a WWB is developed for the current frequency estimation problem. It is evaluated against state-of-the-art estimation bounds. Synthetic results show that the WWB provides a tighter bound than other bounds and thus is a good candidate for exhausting the potentials of any maximum-a-posteriori (MAP) principled estimator.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"56 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":"135483349","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":"Ionospheric VTEC Map Forecasting based on Graph Neural Network with Transformers","authors":"Ruirui Liu, Yiping Jiang","doi":"10.33012/2023.19292","DOIUrl":"https://doi.org/10.33012/2023.19292","url":null,"abstract":"Accurate and timely prediction of Total Electron Content (TEC) in the ionosphere is of paramount importance for various applications such as GNSS positioning and navigation, communication systems, and space weather monitoring. While recent years have witnessed the application of various deep learning techniques to this task, these methods often treat vertical total electron content (VTEC) maps as either images or sequences, disregarding the inherent non-Euclidean (spherical) nature of VTEC maps. Addressing this limitation, our study offers a novel perspective by introducing graph structures to represent VTEC data. This paper presents a groundbreaking approach, GNNTrans, which amalgamates the strengths of graph convolutional networks and transformer architectures to predict TEC. GNNTrans adeptly captures the intricate spatial and temporal dependencies intrinsic to VTEC maps. Through an ablation study, the results demonstrate graph structures and Graph Neural Networks (GNN) are superior to conventional Convolutional Neural Network (CNN) methods in extracting non-Euclidean spatial information from VTEC maps, achieving root mean square errors (RMSE) of 2.58 and 2.66. Additionally, experiments demonstrate GNNTrans’s supremacy over the CODE one-day forecasting product across various dimensions, reducing the RMSE to 3.34 and 1.49 in 2014 and 2018 respectively, in contrast to C1P’s values of 8.74 and 6.41. GNNTrans exhibits remarkable performance in predicting TEC variations across diverse conditions, thus holding promise for heightened accuracy and reliability in ionospheric TEC forecasting.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"29 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":"135483403","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":"Effects of Equatorial Plasma Bubbles Over Real-Time Kinematic Positioning in Low-Latitude Region","authors":"Phyo C. Thu, Pornchai Supnithi, Lin Min Min Myint, Jirapoom Budtho, Susumu Saito","doi":"10.33012/2023.19465","DOIUrl":"https://doi.org/10.33012/2023.19465","url":null,"abstract":"Equatorial plasma bubbles (EPBs) refer to ionospheric irregularities in low-latitude regions, commonly observed after sunset. They originate at the magnetic equator and then potentially spread to mid-latitude region. As cm-level positioning techniques are increasingly important to various segments of society, the performance degradation of these systems due to EPB at low latitudes needs to be investigated. In this work, we analyze the EPB effects on the performances of real-time kinematic (RTK) positioning at the short, medium, and long baselines at low-latitude stations in Thailand. The low-latitudes local ionospheric disturbances such EPBs are shown to degrade the positioning accuracy of RTK in different seasons in 2022. It is found that the positioning errors are higher during the disturbance periods and more severe at the long baselines than the shorter ones, especially during the equinoctial months.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"49 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":"135483604","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":"Positioning and Timing of Distributed Lunar Satellites via Terrestrial GPS Differential Carrier Phase Measurements","authors":"Keidai Iiyama, Grace Gao","doi":"10.33012/2023.19385","DOIUrl":"https://doi.org/10.33012/2023.19385","url":null,"abstract":"Relative positioning, navigation, and timing (PNT) are crucial to support proximity operations of multiple spacecraft in lunar orbit, which is expected to play a key role in upcoming lunar missions. We propose a relative positioning and timekeeping technique in lunar orbit that leverages differential carrier phase measurements of the terrestrial GPS signals. However, using GPS signals in the lunar orbit is challenging due to 1) the clustered GPS satellite direction leading to a low-observable system, 2) the nonexistence of ionosphere delay models for lunar orbit, and 3) the possibility of cycle slips in the low C/N0 signals. We designed a PNT framework that tackles the three challenges above. First, to robustly make the filter converge in a low-observable system, the proposed PNT framework estimates the absolute and relative states in two separate filters, where filter settings (e.g., process noise) can be tuned separately. Second, to remove the signal-in-space errors, the proposed filter utilizes three different differential measurements. The absolute filter estimates time-differenced carrier phase (TDCP) measurements in combination with the pseudorange and pseudorange rate measurements, avoiding the need for estimating the integer ambiguity terms that are low observable. The relative filter estimates the relative orbit and clock offsets by processing the single difference carrier phase (SDCP) measurements, where signal-in-space errors are removed thanks to the short inter-satellite distance compared to the Earth-Moon distance. Using the obtained single difference float ambiguity estimate, the relative filter also fixes the integer ambiguities in double difference carrier phase (DDCP) measurements to improve the relative orbit estimates. Finally, cycleslip corrupted carrier-phase measurements are removed by observing the residuals in the TDCP measurements. We demonstrate the filter’s performance through simulations of two closely operating lunar satellites with different clock grades in the elliptical lunar frozen orbit (ELFO), wherein we showcase higher positioning and timing accuracy compared to code phase-only PNT methods.","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":"135483677","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":"An Integrated RTK/INS/Solid-State LiDAR Method for Large-Scale Vehicle Navigation in High-Mobility Scenarios","authors":"Jiahui Liu, Cheng Chi, Yingchao Xiao, Xin Zhang, Xingqun Zhan","doi":"10.33012/2023.19338","DOIUrl":"https://doi.org/10.33012/2023.19338","url":null,"abstract":"Robust and accurate urban navigation is essential for autonomous driving. For long-time vehicle navigation, Global Navigation Satellite System (GNSS) is indispensable since it provides a low-cost absolute navigation solution, but suffers from signal interference and outages. In this context, LiDAR(Light detection and ranging)-Inertial Odometry (LIO) is an alternative local navigation technique that is robust under most urban scenarios, and the recent availability of low-cost solid-state LiDAR has further enhanced the appeal of LIO. Hence, this article proposes an integrated navigation scheme that combines GNSS RTK (Real-time Kinematic), INS (Inertial Navigation System), and solid-state LiDAR through factor graph optimization, thereby providing robust pose estimation. This word features various experiments conducted in large-scale outdoor environments, showcasing the effectiveness of the proposed method in overcoming GNSS signal blockages during long-term runs. Besides, the presence of GNSS naturally mitigates the accumulation of large-scale errors in the LIO system and improves pose maintenance in high-mobility scenarios where LiDAR is challenged.","PeriodicalId":498211,"journal":{"name":"Proceedings of the Satellite Division's International Technical Meeting","volume":"29 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":"135483683","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}