Variable structure interacting multiple model for highly aperiodic sensors with poor measurement precision

The issue of aircraft tracking using passive sensors with poor measurement precision and a variable update rate is investigated. First, the need for a time‐dependent Markov chain transition matrix for the Interacting Multiple Model (IMM) is thoroughly evaluated using simulation and real data from an experimental multilateration system. Three different methods for computing the time‐dependent matrix are compared, showing their superiority for highly aperiodic sensors. Second, the Variable Structure Interacting Multiple Model (VS‐IMM) for passive sensors with poor geometry is proposed, in which the mode set update is based on local dilution of precision or distance root mean square error. The performance of the estimator is compared with the IMM using real data. The VS‐IMM results in the best performance for areas of both high and low measurement precision.