Fault Detection and Isolation Architecture for GPS Integrity Monitoring

Abstract

There are several techniques that can improve the accuracy and/or integrity of GPS by augmentation. The widespread use of differential correction signals from reference stations using the appropriate maritime radio navigation frequency band between 283.5 and 325 kHz for local augmentation and craft or receiver autonomous integrity monitoring may be mentioned as examples. It is regarded as safety is due to a critical issue for navigation. To ensure the highest level of safety with an acceptable level of service, the International Maritime Organization (IMO) provided the minimum maritime user requirements for a future Global Navigation Satellite System (GNSS) in the Resolution A.915. The requirements are specified in terms of four parameters; accuracy, integrity, availability, and continuity. The requirement parameter that is linked directly to safety is integrity. For safety-critical applications such as harbor entrances and approaches and other waters in which navigation is restricted, it is important to detect and isolate faults that cause accuracy and integrity risks, so that the navigation system can operate continuously without performance degradation. For high accurate systems, the integrity monitoring function needs to detect and isolate small biases. So this paper proposes a fault detection and isolation architecture using Gaussian Particle Filter (GPF). This paper investigates an approach based on a GPF that is a suitable for detecting soft failures affecting only subsets of measurements, such as an erroneous navigation signal from a GPS satellite. The fault detection is then undertaken by checking the consistency between the state estimate of the main GPF and those of the auxiliaries by using likelihood ratio test.