Methods and systems for validating locations

Abstract

This invention relates to methods and systems for determining whether a reference point in a location system has changed used measurement residuals determined from an exchange of messages between reference points. In one embodiment a method of determining whether the location of a first one of a plurality of reference points used in a location system has changed is provided. The reference points each have a known initial position and the method includes the steps of: sending a wireless message between a second reference point and the first reference point and recording the times of sending and receipt of the wireless message; estimating, from the recorded times, an estimated distance between the first reference point and the second reference point; comparing the estimated distance to the actual distance between the known initial positions of the first and second reference points to determine a measurement residual; and determining, using the measurement residual, whether the location of the first reference point has changed.

Dependencies are inferred from the claim text.