A search-and-revist scanning policy to improve the detection rate in radar systems

We propose and analyze a two-step scanning policy for agile-beam radars. In the first step (search) the whole area is scanned, and all returns whose test statistic exceeds the threshold are declared as detections; a revisit phase then follows, where the ambiguity on a subset of returns whose test statistic is close to (but not exceeds) the threshold is solved. It is shown that the additional degrees of freedom provided by the second step (number of revisits and dwell time) can be exploited to increase the detection rate, which is the average number of detections from a target per unit of time. Numerical examples are provided to show the merits of the proposed scanning policy.