Adaptive suppression of smart jamming with FDA permutation

By adding a frequency increment to the carrier frequency of the pulses transmitted from an antenna array, it becomes possible to make the beam dependent on both frequency and range. This is called a frequency diverse array (FDA), and it is known that FDA can improve the system against both clutter and jamming. In this paper, it is shown by simulation, that suppression of the jammer is possible if the FDA increments are randomly permutated. If the jammer is not able to return the radar pulse within the pulse repetition interval (PRI), the radar will expect a return pulse with another FDA patteren in the next PRI. The idea has been tested by simulating a phased MIMO-FDA radar with an 8x2 antenna and four MIMO beams, and by processing the received signals with a recursive Capon estimator.