Study On Subarray Adaptive Interferometric DOA Estimation In The Presence Of Mainlobe&Sidelobe Jamming

The perfomances of estimation methods for target direction of arrival(DOA) whichdepend on monopulse curve will be degraded even failed due to beam patterndistortions resluted from adaptive interference suppression. Subarray processing isusually adopted for reducing hardware complexity and alleviating signal processingburden of large phased array. In the case that the received array signal contain mainlobeas well as sidelobe jamming, a research on adaptive target angle estimation based onsubarray level has been developed. Firstly, three classical adaptive methods forinterference suppression are given and equations of anti-symmetric sum-difference andinterferometric DOA estimations are derived. In suceession, the influence of mainlobeor sidelobe jamming on the performance of DOA estimation is analyzed. Then, a novelmethod for adaptive interferometric DOA estimation utilizing subarray shift invarianceis proposed. That is, the planar array is divided into up and down subarrays satisfyingthat one can be overlaped by the other by shift. The anti-jamming outputs of these twosubarrays are gained by principle compenent beamforming(PCB). The elevation isestimated by an interferometric processing and the azimuth can be estimated by asimilar processing between right and left subarrays. It is proved that DOA estimationshave nothing to do with adaptive beam distortions. Compared with other methods, theproposed method has a better performance of interference suppression and a higherprecision of DOA estimation. Results of measured and simulated data demonstrate theeffectiveness and superiority of the proposed method. Finally, the proposed method isapplied on the signal processing system in a practical engineering project, including taskdivision, work flow, software design and debugging.