Performance Analysis of Mainlobe Canceller for Monopulse At Subarray Level in the Presence of Amplitude-Phase Error

The sum-difference mainlobe canceller (MLC) can suppress mainlobe jamming (MLJ) while maintaining an undistorted monopulse ratio for unbiased angle estimation. The impact of amplitude-phase error on the jamming suppression performance is one of the key problems for MLC implementation in practice. In this article, the quantitative analysis of the MLC technique in the presence of amplitude-phase error is thoroughly studied. By establishing the model of a four-channel MLC for monopulse at subarray level, the concept of angular resolution of the MLC is proposed, and the impact of amplitude-phase error on the angle estimation accuracy is analyzed. Compared with the state-of-the-art analytical methods, the proposed analytical derivations can obtain more accurate theoretical results in various nonideal conditions. Numerical simulations and darkroom experiments verify the correctness of the theoretical analysis. This article presents the theoretical boundaries of the applicable scenarios for the MLC technique in the presence of amplitude-phase error.