Multiple GPS Fault Detection and Isolation Using a Graph-SLAM Framework

Sriramya Bhamidipati and Grace Xingxin Gao

Peer Reviewed

Abstract:	Autonomous vehicles operating in GNSS challenged urban environments are prone to uncorrelated multipath effects in multiple satellite channels. In addition, the increasing number of GNSS satellites due to the addition of new constellations increases the probability of multiple satellite faults caused by broadcast anomalies. We propose a graph-based Simultaneous Localization and Mapping (Graph-SLAM) framework to perform multiple GPS Fault Detection and Isolation (FDI), in particular, satellite faults due to broadcast anomalies and received signal faults due to multipath. SLAM is a well-known technnique in robotics. It utilizes sensor measurements to estimate the landmark features in an unknown 3-Dimensional (3D) map while simultaneously localizing the robot within it. Analogous to this, we design a GraphSLAM framework, where the robot is the receiver, and the landmarks in the map are the GPS satellites. Utilizing the pseudoranges, receiver and satellite motion model, our SLAM-based FDI simultaneously estimates the position, velocity and time of both GPS receiver and satellites. Thereafter, we assess the probability of fault in each satellite by individually evaluating the corresponding test statistic against its empirical cumulative distribution calculated on-the-fly. We validate our algorithm via different experimental scenarios, namely, adding multiple simulated broadcast anomalies to the open-sky data collected using a ground vehicle; flying an aerial vehicle in an urban area prone to multipath. We demonstrate the capability of our algorithm in performing multiple FDI while accurately locating the receiver.
Published in:	Proceedings of the 31st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2018) September 24 - 28, 2018 Hyatt Regency Miami Miami, Florida
Pages:	2672 - 2681
Cite this article:	Bhamidipati, Sriramya, Gao, Grace Xingxin, "Multiple GPS Fault Detection and Isolation Using a Graph-SLAM Framework," Proceedings of the 31st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2018), Miami, Florida, September 2018, pp. 2672-2681. https://doi.org/10.33012/2018.16030
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