Active Frequency Diverse Array Counteracting Interferometry-Based DOA Reconnaissance

In order to counter passive direction-of-arrival (DOA) reconnaissance for unintended eavesdroppers, this letter proposes the use of frequency diverse array (FDA) to counteract passive DOA reconnaissance using a virtual baseline interferometer. FDA applies a small frequency offset across its array elements to generate an angle-range-dependent and time-variant transmit beampattern, which provides a potential capability to achieve radio frequency (RF) stealth and localization deception for eavesdropping receivers. We analyzed the DOA localization deception of FDA transmitting signal, together with simulation examples. The results show that, while compared to conventional phased-array transmitting signal, RF localization deception of DOA estimation is indeed achieved for the FDA transmitted signals, which provides promising potentials for future secure radar and communication applications.

I. Introduction

Passive source localization has attracted increasing attention in recent years due to its strong concealment and good flexibility. Typical source interception techniques include receive signal strength, time of arrival, direction of arrival (DOA) [1]–[3], time difference of arrival, frequency difference of arrival [4], etc. To reduce transmitter visibility, several low probability of intercept (LPI) [5] or radio frequency (RF) stealth [6] schemes were proposed in the literature. Although stealth has been defined for nearly half a century and used operationally for more than 20 years [7], which provides the user a significant advantage over his adversary by making it more difficult for an adversary to detect an opponent, current stealth technologies mostly concentrate on low observability by reducing radar cross section. Differently, this letter considers the use of a new array technology to increase the system survivability against unintended passive interceptors.