Signal-level Integrity and Metrics Based on the Application of Quickest Detection Theory to Multipath Detection

Multipath is one of the major impairments that can threat the integrity of mass-market GNSS receivers (i.e. those mainly used in terrestrial environments). In this context, the purpose of this work is to adopt a quickest detection framework for multipath detection in single-antenna GNSS receivers. This is done with the aim of providing signal-level integrity in GNSS applications. Three different approaches, all of them using the correlator output samples, are proposed in order to cope with a wide range of multipath and NLOS conditions. The results obtained in real field tests confirm the suitability of the proposed post-correlation metrics and the quickest detection framework to improve the navigation performance and to perform real-time quality monitoring. The novelty of this work is the proposal of sequential tests for multipath detection based on quickest detection theory, which provides an optimum level of signal integrity in terms of the trade-off between delay in detecting integrity threats and time between false alarms. This is in contrast to classical detection techniques, where the goal is to maximize the detection probability subject to some probability of false alarm, but where “time” is not explicitly considered.