A combined particle/Kalman filter for improved tracking of beam aspect targets

Track continuity is difficult to maintain when tracking beam aspect targets. The loss of Doppler discrimination allows clutter to mask the target return, making it nearly impossible to detect. In order to improve tracking performance, a combination particle/Kalman filter has been developed. The tracking filters obviate each other as appropriate. When a target enters a Doppler blind zone, the particle filter replaces the Kalman filter as the tracking algorithm until the target exits the zone. The particle filter expands over the uncertainty region so that when the target is once again visible, it can immediately resume track via re-initialization of the Kalman filter. This paper discusses the design and simulation of this algorithm and shows the resulting improvement in track continuity. We briefly discuss how our combined particle/Kalman filter approach can be used to address the problem of targets obscured in altitude return.