Frequency Diverse Array Radars: Beampattern Design and Target Parameter Estimation

Abstract

The frequency diverse array (FDA) radar beampattern depends on the angle, time and range whereas phased array radar has angle-dependent beampattern only. Therefore, the FDA is more attractive and flexible than phased-array radars. The beampattern design is important for effective target localization. In this thesis, transmit array weights optimization is performed using the IFFT algorithm to design a transmit beampattern to illuminate the desired angular direction and range. The designed beampattern has a high dwell time, and therefore, it can accurately detect even weak targets with a high probability. Each target is characterized by its range and angle. Thus, estimation of both the angle and range for the proposed FDA radar is performed to accurately locate the target using the double-pulse method. The double-pulse method first transmits a pulse with zero frequency offset to determine the angle of the target independently, and then another pulse is transmitted at a non-zero frequency offset to determine the range of the target by using the estimated angle. The proposed scheme can also minimize noise effects using the minimum power distortionless response (MPDR) beamformer at the receiver. Therefore, the target parameter estimation method is used to determine the exact 2D spatial location of the target. In addition, the Cramer- Rao lower bound (CRLB) for the FDA radar is derived. The root-mean-squared error (RMSE) for both the angle and range is plotted to compare the existing FDA radar performance with the proposed FDA radar and simulations are performed to verify the results.