Revisit calculation and waveform control for a multifunction radar

Abstract

Since phased array radars have the ability to perform adaptive sampling of the target trajectory by the radar beam positioning, proper control of the radar has the potential for significantly improving many aspects associated with the tracking of multiple manoeuvring targets. The technique proposed in this paper uses the interacting multiple model (IMM) algorithm to track manoeuvring targets and control the revisit time, and pointing, and adjust the energy level of the radar. Since the output of the IMM algorithm better represents the accuracy of the state estimates during a manoeuvre than that of a single model filter, the IMM algorithm is used to compute an online measure of tracking performance to determine the revisit time of the next track update in order to maintain a given level of performance. The revisit time is computed as the one positive root of a polynomial equation of the sample period. The model probabilities of the IMM algorithm are also used to schedule the energy level of a radar dwell. As a result, the revisit times are a function of track filter performance and the target trajectory. Algorithms for computing the revisit time, pointing the radar, and adjusting the energy level using the output of the IMM algorithm are presented in this paper. Performance comparisons are given for the IMM algorithm using a constant data rate, adjusted energy levels, and an adaptive data rate. >