A new method for satellite navigation signals FDI

Integrity of signals is an important issue for aerospace navigation systems and, in particular, for satellite navigation positioning. In this paper integrity monitoring techniques are processed with a new FDI technique implemented by a snapshot RAIM algorithm, based on linearized models, and position domain tests. The approach consists of the joint exploitation, in an Errors In Variables (EIV) framework, of all the possible Least Squares (LS) solutions under the hypothesis of a single fault on a pseudorange measurement. The characteristics of the behavior of the different LS position and bias estimates, by varying the fault size and the faulty satellite, are investigated. The non linear dependence of the locus of the solutions from the fault size is considered. The analysis of the loci properties results in a new criterion and algorithm for the detection and isolation of a faulty satellite signal. The effectiveness of the proposed method has been compared with respect to a classic FDI method by means of Montecarlo simulations based on a Galileo constellation simulator.