# An Angle Estimation Approach for Coherent FDA Radar Based on Transmit-Receive Sum and Difference Beamforming

## TL;DR

This paper introduces a new method for improving angle estimation in radar systems using a special type of array with frequency diversity.

## Contribution

The novel approach uses transmit sum and difference beamforming to achieve high-precision angle estimation in coherent FDA radar.

## Key findings

- The method achieves an angular resolution of 1/20 of the beamwidth at 20 dB SNR.
- It maintains FDA system advantages while enabling accurate angle estimation.
- The technique shows robust performance across various scenarios.

## Abstract

This paper proposes a high-precision angle estimation method based on transmit sum and difference beamforming for coherent frequency diverse array (FDA) radar. By employing a small frequency offset across the array aperture, the coherent FDA radar achieves a range-angle-coupled transmit beampattern that combines wide transmission coverage with narrow reception capability. The proposed method constructs an equivalent two-dimensional coupled sum-difference beam in the target output channel by simultaneously utilizing signal detection outputs from multiple transmitted beams. This approach maintains the inherent advantages of FDA systems while enabling accurate angle estimation without sacrificing coverage. Simulation results demonstrate that the proposed architecture achieves an angular resolution of 1/20 of the beamwidth at a signal-to-noise ratio (SNR) of 20 dB, significantly outperforming conventional techniques. The method exhibits robust performance in various scenarios, which makes it a good candidate for modern radar applications requiring both wide-area surveillance and high-precision angle measurement.