| Airborne early warning radar,due to the increased altitude of the carrier platform,can effectively overcome the limitations of the earth’s curvature and ground obstructions,and achieve detection of distant or low-altitude targets,playing a significant role in target warning,battlefield surveillance and other fields.In recent years,the increasingly complex battlefield environment and diverse small targets have made the existing airborne radar signal processing architecture prone to losing weak target signals,which brings great difficulties to the task assignment of the command center.Therefore,designing strategies for detecting weak targets in complex clutter backgrounds for airborne radars has become extremely urgent and important.Multi-frame clutter suppression and target detection technology refers to combining the multi-circle echo of airborne radar,adjusting the merit function accumulation strategy of multi-frame joint detection(MFD)technology according to the clutter property of different airborne radar operating modes and different radar array arrangement,forming a joint configuration of clutter suppression and detection,and finally realizing the efficient detection of weak targets under complex clutter background.In traditional airborne radar signal processing,there are problems such as low target detection probability and high clutter false alarm.Based on this,this thesis focuses on the research of MFD technology in clutter environment of airborne radar.The main research work and contributions are as follows:1.A relative path search based MFD algorithm for airborne radars is researched under the conventional signal processing mode of airborne radars.The algorithm can effectively achieve target detection and tracking under measurement-state mismatch conditions,laying the foundation for subsequent algorithms.2.For airborne pulse Doppler(PD)mode,the range non-stationarity of non-sidelooking airborne radar clutter in PD mode is analyzed.A multi-frame clutter suppression and detection method based on local energy compensation is proposed.The proposed method can effectively suppress near-range clutter.After multi-frame accumulation,there are few false alarm points and the target detection probability is high.3.The clutter suppression mechanism of space-time adaptive processing(STAP)mode is studied by establishing a clutter model of space and time.A multi-frame clutter suppression and detection algorithm based on spatial relative addressing is proposed to solve the problem of target spatial mismatch,with higher detection benefits and stability than traditional algorithms.4.The test flight data of airborne early warning radar is used to test the application of the proposed method in the real radar detection scene.The processing results confirm that the proposed algorithm can effectively suppress background strong clutter,greatly reduce the number of false alarm points and false track compared with traditional signal processing methods,and at the same time has robust detection ability.All of the above work has been validated with simulation and some algorithms have been verified by radar real measured data,which confirms the effectiveness of the proposed algorithm demonstrating high-performance detection of weak targets in airborne clutter backgrounds and verifying the effectiveness of the proposed algorithms. |
PDF Full Text Request