Resolving RIPS measurement ambiguity in maximum likelihood estimation

A Radio Interferometric Positioning System (RIPS) is able to measure the sum of distance differences between four sensor nodes. If the locations of the three out of four sensor nodes are known, that of the fourth node may be determined using RIPS measurements via the techniques of hyperbolic positioning. One of the key issues with RIPS is the measurement ambiguity because of the wrapping of distance by phase measurements. Solutions to this RIPS measurement ambiguity problem often require extensive computational power which is vital to some wireless network of small sensors. In this paper, we describe an efficient stochastic method to practically resolve RIPS measurement ambiguity under the criterion of Maximum likelihood estimation. Our simulation results demonstrate the effectiveness of the proposed algorithm.