New 3D-Mapping-Aided Approach for User Integrity Monitoring in Urban Environments using a Nonparametric Positioning Errors Modeling

N. Kbayer and M. Sahmoudi

Abstract:	In order to foster the development of Global Navigation Satellite Systems (GNSS) for land navigation services, there is a pressing need for providing a trust level of the degradation on positioning errors, especially for liability critical applications. In view of such need, integrity monitoring aims to compute protection levels that successfully bounds positioning errors in harsh environments. Unlike open sky areas, it is well known that GNSS positioning errors in these environments are very difficult to be characterized by a parametric statistical distribution due to the high variability of the environment. Therefore, we propose in this paper to investigate a nonparametric estimation scheme for error characterization. We focus on overcoming the traditional Gaussian model assumption used in traditional monitoring techniques for integrity monitoring in urban settings. First, we use a 3D GNSS simulator for intensive simulations to model the positioning errors with a nonparametric distribution. This distribution is estimated from a number of 3D PR bias samples generated using the GNSS simulator over a sliding time window and on a grid of input points. Then, we follow a nonparametric approach to estimate the quantile function of the empiric distribution to compute new protection levels with better performances than least square residual RAIM. This methodology provides a new method of computing the Horizontal Protection Level (HPL) without assuming an explicit parametric model for positioning errors. A checking test for fault detection and exclusion is also derived and evaluated in a dynamic urban environment. The key and the novel idea in this work is the use of external information (3D GNSS simulator) for computing more reliable and robust protection levels than stand-alone receiver-based integrity monitoring methods.
Published in:	Proceedings of the 2017 International Technical Meeting of The Institute of Navigation January 30 - 2, 2017 Hyatt Regency Monterey Monterey, California
Pages:	92 - 104
Cite this article:	Kbayer, N., Sahmoudi, M., "New 3D-Mapping-Aided Approach for User Integrity Monitoring in Urban Environments using a Nonparametric Positioning Errors Modeling," Proceedings of the 2017 International Technical Meeting of The Institute of Navigation, Monterey, California, January 2017, pp. 92-104. https://doi.org/10.33012/2017.14963
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