# High-Precision 2D-DOA Estimation Method for Millimeter-Wave Radar Based on Double-Parallel Linear Array and Joint IAA-RIT

## TL;DR

This paper introduces a new method for accurately estimating the direction of arrival in millimeter-wave radar using a combination of advanced signal processing techniques.

## Contribution

The novel contribution is a joint IAA-RIT method for high-precision 2D-DOA estimation using a double-parallel linear array.

## Key findings

- The proposed method achieves high-precision 2D-DOA estimation with limited snapshots.
- The IAA-RIT method effectively decouples azimuth and elevation angles without additional angle matching.
- The method successfully handles coherent signals and improves radar target detection accuracy.

## Abstract

High-precision two-dimensional direction of arrival (2D-DOA) estimation is an important mean of millimeter-wave radar for accurate target location. Aiming at the problems such as limited antenna aperture, signal coherence, and a few snapshots in millimeter-wave radar target detection, this paper proposes a 2D-DOA estimation method by using a joint iterative adaptive approach and rotational invariance technique (IAA-RIT) based on the double-parallel linear array. This method first constructs an iterative adaptive approach spectrum based on subarray 1 in the double-parallel linear array and then calculates the coupling angle estimate with the azimuth and the elevation. Secondly, based on the rotational invariance relationship between the two subarrays, the extended covariance matrices are respectively constructed, and the spatial smoothing technique is employed to decorrelate the signals. Then, the signal direction matrix is reconstructed based on the coupling angle estimate, and the rotational invariance relationship between the two subarrays is calculated to obtain another set of coupling angle estimates. Finally, the azimuth and the elevation are decoupled based on two sets of estimated coupling angles and the spatial geometry relation. Our experimental results show that IAA-RIT can estimate the coherent signal with high-precision 2D-DOA with a few snapshots and no additional angle matching.