Mitigação de Efeito Spoofing em GNSS na pré-correlação

Abstract

GNSS (Global Navigation Satellite System) can be used in both military and civil applications to provide continuous, safe and reliable positioning, speed and measurement and timing services for users who need navigation services location, financial services and energy distribution. Using this system requires reliable position estimation and a major risk to this position estimation is the so-called threat of spoofing. A spoofer can fabricate false signals to trick a GNSS receiver into estimating the wrong position for the user. Unlike jamming, which aims to interrupt GNSS signals, spoofers are technically more elaborate. By replicating GNSS signals, a spoofer can trick the receiver into thinking it is somewhere else at that time and unlike jamming, the user does not easily detect it. Much research addresses spoofing detection and mitigation considering several different techniques and strategies. In this work, we present a pre-correlation spoofing mitigation approach considering a system with several sensors. This approach is independent of the considered GNSS signals or constellation, either considering open or authorized services. In this work, we assume a loose integrated receiver where the anti-spoofing sub-system is processing signals of the antenna array and then passes a spoofing-free signal to the connected GNSS receiver. Thus, the GNSS receiver is considered a state-of-the-art with no specific features. The spoofing detection based on the direction of arrival (azimuth and elevation) estimation, the subsequent spoofing mitigation by spatial filtering and the continued reception and processing of the GPS satellites will be discussed. This approach can be considered a so-called blind adaptive approach, as neither the signal characteristics nor the DOAs of the signals are known by the receiver in advance. A static receiver with 7 sensors and a static attacker/spoofer with 1 receiver antenna is assumed.