Failure detection approach applying to GPS autonomous integrity monitoring

In recent years, there has been a growing interest within the potential user community in applying GPS to a variety of high-precision navigation problems such as aircraft nonprecision approach, river and harbour navigation, real-time or kinematic surveying, etc. In view of more and more GPS applications, the reliability of GPS is at issue. This promotes the need for several proposed receiver autonomous integrity monitoring (RAIM), GPS integrity channel (GIC), and wide area augmentation system (WAAS) schemes. The authors propose an approach for autonomous GPS satellite failure detection. The method exploits total least squares (TLS) optimisation to achieve fault detection. The traditional least squares approach fails to address the change in the data matrix associated with GPS satellite constellation. This drawback is shown to be remedied by the total least squares method. The proposed method can further be extended to account for failure isolation in which failed GPS satellites are identified and hence excluded in positioning.