Abstract
Flow fields naturally measure the time to contact (TTC) between two objects and are symbolized by the parameter "tau". Hence, the term echoic flow represents the use of flow fields in active sensing systems like, radar and sonar. In this paper, we examine the use of the time derivate of the echoic flow parameter "tau dot" in cognitive radar for target following and approach control applications. After a brief introduction of the echoic flow concept and its derivative, three target movement scenarios stationary target, target moving slower than radar platform and target moving faster than radar platform-are analyzed using both simulations and experiments. The effect of range and range rate measurement accuracy on echoic flow is discussed and methods to achieve suitable levels of accuracy presented.