Method of estimating location and orientation of magnetic dipoles using extended Kalman filtering and Schweppe likelihood ratio detection

摘要

A method for real time processing of information received from a plurality of permanent magnets embedded in the pavement of an Intelligent Vehicle Highway System. A sequence of magnet orientations provides coded information to sensors mounted on automotive vehicles. The method uses a combination of extended Kalman filtering and Schweppe likelihood estimation to determine the relative location and orientation of the magnets. A separate location estimator (extended Kalman filter) is provided for each of the possible magnet orientations. A decision process identifies the most likely orientation of the magnet, and the Kalman filter selected by the process contains the best estimate of the location of the magnet. Schweppe likelihood estimation is extended to use the detector as a decoder of the information provided by the orientation sequence of the magnets. Failure of the decision process to arrive at a clearly defined decision (resulting, for example, from a missing or defective magnet) can be carried to a higher decoding level in which possible sequences of orientations and their relative likelihood can be used to select the most likely sequence.