Cognitive frequency diverse array radar with symmetric non-uniform frequency offset

Abstract

Frequency diverse array (FDA) radar with uniform inter-element frequency offset generates a beam pattern with maxima at multiple range and angle values. Multiple maxima property allows interferers located at any of the maxima to affect the target-returns. As a result the signal to interference noise ratio (SINR) and probability of detection decreases. In this paper, we propose a cognitive uniformly-spaced FDA with non-uniform but symmetric frequency offsets to achieve a single maximum beam pattern at the target position. Moreover, these non-uniform frequency offsets are calculated using well known mu-law formulae. The design sharpens or broadens the transmitted beam pattern based on the receiver feedback to achieve a better detection probability and an improved SINR as compared to the previous designs. The performance is also analyzed by considering the Cramer-Rao lower bound (CRLB) on target angle and range estimation.