A methodology for incorporating the Doppler blind zone in target tracking algorithms

The problem of tracking targets, where measurements may occasionally be masked by the Doppler blind zone of the sensor, arises in Ground Moving Target Indicator tracking and aerial surveillance. For such problems, no target return is registered when the range rate (Doppler) of the target falls below a sensor-specific threshold in magnitude. For this reason, possible missed detections provide kinematic information about the target, and it is of interest how to incorporate this information in tracker design. In this paper, we introduce a new methodology for tracking under Doppler blind zone constraints, based on Gaussian mixture approximations to the conditional density. The filter equations are based on analytic calculations of the posterior density, while the Gaussian mixture approximation step is carried out over a scalar variable and involves exact moment matching. The presence of clutter and the employment of jump Markov models to describe target motion are naturally covered by the new paradigm. Simulation results indicate performance improvements over other analytic techniques and comparable accuracy of estimation with high-order particle filters.