| With the development of missile, statellite and aerospace, the more excellent performance is demand on speed, accuracy and range of tracking radar.The situation is made worse as a result of the introduction of anti-radar technology, stealth technology, counter-radiation missile and electromagnetic jamming. The ability of countering passive jamming and active jamming is emphasized in modern radar. It is an effective way to enhance this counter-jamming ability using array antenna.The monopulse technique uses simultaneously lobing, which have the performance of fast acquiring error signals and tracking speed, high accuracy and robust anti-jamming ability. This paper is about the application of array antenna radar using monopulse. The estimation of direction of arrival is accomplished with monopulse technique using digital beamforming.Firstly, the paper introduces the conception, theory and mathematical model of the array antenna. Serval algorithms of adaptive beamforming and DOA are analyzed using MATLAB software.After introducing sequential lobing and conical scan tracking technique, the theory of the phase comparison and amplitude comparison monopulse are also discussed. This paper has also designed a high-gain, low-sidelobe conical horn.The monopulse technique for DOA estimation degrades serverely when there is sidelobe jamming and/or mainlobe jamming. If not effectively countered, electronic jamming can prevent successful radar target detection and tracking. Constraint-adaptive array monopulse digital beamforming architecture and processing algorithm is described for nulling the signal from a mainlobe electronic jammer and multiple sidelobe electronic jammers while maintaining monopulse angle estimation accuracy on the target. In this approach, the sum beam is optimized without any constraint while the difference beam is optimized such that the monopulse slope is preserved along the elevation and azimuth. The analytical evaluation in the last chapter confirms the solution. |
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