NLOS Mitigation Methods for Geolocation

The problem of locating mobile sensors has received considerable attention, particularly in the field of wireless communications. It is well known that the presence of non-line-of-sight (NLOS) errors in the geolocation problem leads to severe degradation in the localization performance. This chapter introduces NLOS mitigation methods for geolocation. Generally, the NLOS mitigation methods for geolocation can be grouped into four categories: maximum likelihood (ML)-based techniques, least squares (LS)-based techniques, constrained optimization techniques and robust estimator techniques. The chapter discusses these methods, and then compares these methods in terms of different performance measures. It also discusses a novel geolocation example using a single moving sensor. The chapter then presents numerical examples to demonstrate how position estimation can be achieved for the case of a single moving sensor with NLOS errors. Controlled Vocabulary Terms error correction; least squares approximations; maximum likelihood estimation; optimisation; position measurement