Tracking filter initialization with Doppler-biased multistatic time-of-arrival measurements

We discuss the multistatic target tracking problem in which the target is illuminated by Doppler tolerant waveforms (DTW). DTW introduce a bias to the true time-of-arrival, as a result of which the corresponding range measurement accuracy is degraded when this bias is ignored. An important part in the design of a tracking filter using nonlinear measurements is the initialization: the initial state estimate should be unbiased and the associated covariance should be consistent with the errors. This paper presents a maximum likelihood based method as well as a simpler iterative bias cancellation method to initialize a tracking filter from two observation frames. The iterative method makes it possible to obtain unbiased initial position and velocity estimates by canceling out the Doppler bias. Simulation results show that both estimators are efficient.