Weighted Least Squared Approach to Fault Detection and Isolation for GPS Integrity Monitoring
Abstract: Reliability of a
global navigation satellite system is one of great importance for global
navigation purposes. Therefore, an integrity monitoring system is an
inseparable part of aviation navigation system. Failures or faults due to
malfunctions in the systems should be detected to keep the integrity of the
system intact. In order to solve the problem that least squares method detects
and isolates a satellite fault for GPSintegrity monitoring, in this paper, a
weighted least squares algorithm is proposed for satellite fault detection and
isolation. The algorithm adopts the diagonal elements of the covariance matrix
of GPS measurement equation as the weighted factor. Firstly, the weighted least
squares approach for satellite fault detection establishes the test statistic
by the sum of the squares of the pseudo-range residuals of each satellite for
GPS. Then, the detection threshold is obtained by the false alarm rate of the
fault detection, probability density function and visiable satellite number.The
effectiveness of the proposed approach is illustrated in a problem of GPS
(Global Positioning System) autonomous integrity monitoring system. Through the
real raw measured GPS data，based on least squares RAIM method and theweighted
least squares RAIM approach, the performance of the two algorithms is compared.
The resultsshow that the proposed RAIM approach is superior to the least
squares RAIM algorithm in the sensitivity of fault detection and fault
isolation performance for GPS integrity monitoring.
Keywords: Global Navigation
Satellite System (GNSS), Global Positioning System (GPS), Receiver Autonomous
Integrity Monitoring (RAIM), Weighted Least squares method, Fault detection, BeiDou
Navigation Satellite System (BDS)
Author: Ershen Wang
Journal Code: jptkomputergg170146
