Monopulse Parameter Estimation based on MIMO-STCA Radar in the Presence of Multiple Mainlobe Jammings

TL;DR

This paper introduces adaptive beamforming algorithms for MIMO-STCA radar to suppress multiple mainlobe jamming sources, maintaining accurate monopulse angle estimation and enabling joint angle-range estimation in complex electromagnetic environments.

Contribution

The paper proposes novel row-column adaptive beamforming algorithms that suppress multiple mainlobe jamming sources while preserving monopulse ratio accuracy, and enables joint angle-range estimation using MIMO-STCA radar.

Findings

Effective suppression of multiple MLJs demonstrated in simulations.

Maintains monopulse ratio integrity during jamming suppression.

Achieves low RMSE in joint angle-range parameter estimation.

Abstract

The monopulse technique is characterized by its high accuracy in angle estimation and simplicity in engineering implementation. However, in the complex electromagnetic environment, the presence of the mainlobe jamming (MLJ) greatly degrades the accuracy of angle estimation. Conventional methods of jamming suppression often lead to significant deviations in monopulse ratio while suppressing MLJ. Additionally, the monopulse technique based on traditional radar cannot jointly estimate the target's range. In this paper, the four-channel adaptive beamforming (ABF) algorithm is proposed, which adds a delta-delta channel based on conventional sum-difference-difference three-channel to suppress a single MLJ. Moreover, considering the suppression of multiple MLJs and sidelobe jammings (SLJs), the row-column ABF algorithm is proposed. This algorithm utilizes more spatial degrees of freedom (DOFs) to suppress multiple jammings by the row-column adaptive beamforming at the subarray level. The key ideal of both algorithms is to suppress MLJ with null along one spatial direction while keeping the sum and difference beampatterns undistorted along another spatial direction. Therefore, the monopulse ratio remains undistorted while suppressing the MLJ, ensuring the accuracy of monopulse parameter estimation. Furthermore, by utilizing the additional degrees of freedom (DOFs) in the range domain provided by the multiple-input multiple-output space-time coding array (MIMO-STCA) radar, joint angle-range estimation can be achieved through the monopulse technique. Simulation results highlight the effectiveness of the proposed methods in suppressing multiple MLJs and enhancing the accuracy of monopulse parameter estimation, as verified by the low root mean square error (RMSE) in the parameter estimation results.