Cognitive null steering in frequency diverse array radars

Abstract

Null steering has been a challenge in radar communications for the past few decades. In this paper, a novel cognitive null steering technique in frequency diverse array radars using frequency offset selection is presented. The proposed system is a complete implementable framework that provides precise and deep null placement in the range and angle locations of the interference source. The proposed system is cognitive such that the transmitter and receiver are connected via a feedback loop. System extracts interference source location parameters from the radar scene using Multiple Signal Classification, a super resolution direction of arrival estimation technique. Neural networks known for minimum computation time, and good non-linear and non-parametric approximation have been utilized for prediction of next location of the interference source. Simulation results validate the proposed frequency offset selection by demonstrating precise and deep nulls at the desired locations.

Adaptive transmit beamspace design for cognitive FDA radar tracking

“…Suppose the Eigen vectors of are , then we define that represents the Eigen vectors except the ones corresponding to the L largest Eigen values. Therefore, the spatial spectra can then be represented by [27] The sources’ DOAs can be estimated from the spatial spectra peaks. Thereafter, the sources’ ranges can be computed as [28] where and denote the total trip time and wavelength, respectively.…”

Development of frequency diverse array radar technology: a review

“…Likewise, in [99], an FDA with a time‐dependent frequency offset was proposed to get improved beam pattern for a given range and direction. A null steering technique using suitable frequency offsets for an FDA radar has been presented in [100] for improved interference cancellation.…”

“…Moreover, a frequency offset calculation method based on the receiver feedback was proposed in [98] to improve the transmit energy focusing performance in the target position. Moreover, cognitive null steering using a cognitive FDA was proposed in [100], to improve the interference suppression performance. A symmetric cognitive FDA radar design with non‐uniform frequency offsets along the array was proposed in [116], to generate a signal maximum sharp and wide beam pattern according to the requirement, received as feedback from receiver, for enhanced target detection, SINR and CRLB‐based estimation performance.…”

Overview of frequency diverse array in radar and navigation applications

“…Inspired by that cognitive radar is a transmitter‐centric closed‐loop radar system, where it can real‐time exploit its environment to update current probabilistic understanding of the channel, cognitive FDA radar is proposed in [99, 100]. Since FDA creates a range‐dependent beampattern whose amplitude and spatial distribution can be controlled by the frequency increment, we can iteratively adjust the frequency increment in a closed‐loop way to control the transmitted energy distribution to suppress range–angle‐dependent interferences.…”