Anew target localization method for bistatic FDA radar

Different transmit antenna elements in a frequency diverse array (FDA) radar transmit different frequencies. This makes the transmitted beam to continuously change its orientation, and enables an FDA to scan the space around itself in a simple manner. Furthermore, an FDA can find the range as well as the direction of each target simultaneously. The achievable resolution of direction estimation depends on the receive array geometry. The range resolution can be enhanced by decreasing the width of transmit beam, which depends on the transmit array geometry. The later property makes FDA especially attractive because it is no longer necessary to produce sharp, wideband, and high power pulses to achieve high range resolution. FDA has been studied mostly for collocated transmit and receive array, and a very little has been done on its application in bistatic radar. In this paper we propose a new signal transmission scheme for bistatic FDA radar, and demonstrate how one can detect and localize the targets accurately using a computationally efficient algorithm. The proposed signal transmission scheme is designed to produce the narrowest transmit beam for a given number of transmit antennas. This achieves significantly better detection and localization performance compared to the existing methods. Our estimation approach uses a fast algorithm to produce some initial estimates that can be used to initialize a numerical algorithm for computing the maximum likelihood estimates. We also derive the Cramer Rao bound (CRB) associated with the estimation problem, and demonstrate that the variances of the estimates produced by the proposed method are close to corresponding CRBs. (C) 2020 Elsevier Inc. All rights reserved.

Automated summary

Frequency diverse array (FDA) radar transmits different frequencies from different antenna elements, continuously changing the orientation of the beam and making it easier to scan surrounding space. It can detect the range and direction of targets simultaneously, with resolution depending on array geometry. A new signal transmission scheme for bistatic FDA radar is proposed in this study, showing improved detection and localization performance compared to existing methods. The method produces initial estimates using a fast algorithm, with variances close to the Cramer Rao bound.