Multi-Antenna Techniques for NLOS and Spoofing Detection Using Vehicular Real Signal Captures in Urban and Road Environments

E. Domínguez, J.M. López-Almansa, G. Seco-Granados, J. Salcedo, D. Egea, E. Aguado, D. Lowe, D. Naberezhnykh, F. Dovis, J.P. Boyero

Peer Reviewed

Abstract:	The use of GNSS has expanded to mass market users and most of them are located in populated areas and roads where local environmental characteristics, which include buildings, trees, moving objects, etc., increase the multipath and the Non-Line-of-Sight (NLoS) effects, thus dominating the GNSS measurement errors. Also threats like radio frequency (RF) interference and spoofing can affect the positioning service. These local characteristics, which cannot be corrected by the ground or satellite segments, degrade the signals leading to potentially high positioning errors and therefore may also hinder the provision of a full integrity positioning service. The purpose of the current study is to assess the possibilities that a mass-market level multi-antenna device could offer in order to improve integrity by identifying faulty measurements (i.e. high error measurements). Using the real data collected with a GPS&GLONASS single-frequency three-antenna array in urban and road environments, the paper presents the results obtained applying several multi-antenna techniques at PVT level aimed to cope with local effects by identifying high error measurements to improve the navigation solution (meas. errors were obtained using a high quality truth reference platform and dedicated post-processing software). Thus, different multi-antenna indicators are analyzed assessing their capability of detecting high error measurements and then several combinations of indicators are used as a Fault Detection and Exclusion (FDE) and tested with a navigation algorithm in order to assess their impact on the position errors. One of the main objectives of the study is to assess the possibility of exploiting the multi-antenna FE phase measurements to identify NLoS measurements in urban environments; this is because antenna phase differences contain information related to the direction of arrival (DoA) of the received signals, also known as angle of arrival (AoA). NLoS measurements do not usually arrive from the expected DoA, which for direct signals can be obtained from user attitude and satellite Line-of-Sight (LoS), so this turns phase differences into a potential indicator that can be used to detect NLoS. Besides, the paper demonstrates how, only using the antenna phase differences, the presence of a spoofer can be detected when the spoofing signals arrive from the same direction. This can be done without any external info, even without calibrating the difference between the antenna HW biases.
Published in:	Proceedings of the 28th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2015) September 14 - 18, 2015 Tampa Convention Center Tampa, Florida
Pages:	2966 - 2982
Cite this article:	Domínguez, E., López-Almansa, J.M., Seco-Granados, G., Salcedo, J., Egea, D., Aguado, E., Lowe, D., Naberezhnykh, D., Dovis, F., Boyero, J.P., "Multi-Antenna Techniques for NLOS and Spoofing Detection Using Vehicular Real Signal Captures in Urban and Road Environments," Proceedings of the 28th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2015), Tampa, Florida, September 2015, pp. 2966-2982.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In