Angle Estimation of a Second Target in Monopulse Radar via Separation-Confirmation Method Given the DOA of the Other Target

Le résumé fourni par la source

Conventional three-channel monopulse systems necessitate prior knowledge of the power ratio between two unresolved targets to facilitate angle estimation. When a significant power disparity exists, the estimated angle of the weaker target exhibits a bias toward the stronger target. This paper proposes a robust three-channel dual-target angle resolution method that operates without relying on polarization information or expanding to a four-channel configuration. By leveraging readily available prior angle information of one target, the proposed method resolves the angles of two targets within the 3 dB beam mainlobe. This feature enhances its applicability to traditional sum-difference monopulse radar systems with constrained radio-frequency front-end resources. The processing pipeline consists of two key steps: separation and validation. In the separation step, an oblique projection matrix is constructed based on the presumed angle vector of the unknown target and the prior angle vector of the known target to effectively isolate the components of the two targets in the received data. Then, a cost function is designed to evaluate the separation outcome by exploiting the rank-2 characteristic of the echo. Theoretically, the cost function achieves its global minimum if and only if the two target components are correctly isolated. To reduce the computational complexity associated with searching for the unknown target's angle vector, a pre-projection operation is applied to the received data. This operation constrains the solution to a defined line within the angle domain. The angle corresponding to the minimum value of the cost function along this line is then identified as the estimated angle for the unknown target. Comprehensive performance evaluations, conducted through extensive numerical simulations and real-data processing, demonstrate the superiority of the proposed method over existing state-of-the-art approaches, particularly in scenarios with significant power disparities.

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