Vhf Radar Angle Measurement Algorithm

Followed with the modernization of military, surveillance radar played an irreplaceable part in modern warfare. That engendered EW of jamming and anti-jamming, stealth and anti-stealth, destruction and anti-destruction around radar .In EW, detection for stealth target was an important problem which must be solved. As metric electromagnetic wave can not be imbibed availably by stealth aircrafts, research on metric radar obtained more and more attention. As metric radar has its own characteristic, compared to other radar, new problems will appear when goniometry in metric radar was researched.In the last few years, theory and arithmetic in array signal processing improved at a very high speed , and it is possible to use the theory in radar . Using theory of array signal processing in radar can gain several benefits as anti-jamming and high precision of angel measurement . High precision of angel measurement was what the text mainly focused on.The text first discussed the mathematic inbeing of basic theory and arithmetic in estimation of spatial spectrum, analyzed two model arithmetic: MUSIC and DBF. Then simulated and analyzed several questions in engineering simply.Then the question of sidelobe cancellation for antenna array was discussed and analyzed. The text also did research on capability of sidelobe canceller in condition that antenna array are turning or holding steel, and the influence of the DOA estimation the sidelobe cancellation may caused.In the last part of the text, the most important problem of metric radar - how to solve the influence of measuring elevation by the reflect signal of the ground is researched, and we find out that several typical spatial smoothing arithmetic need too much snapshots to solve the problem. To solve the problem, an improved DBF arithmetic is pointed out in the idea of maximum-likelihood by correct the mathematic model of DBF arithmetic in condition that reflection exist .Simulation proved that the value of estimation of elevation is a exact estimation when reflect exist in the typical range 0.6°to 20°, and the precision of the method is better than typical spatial smoothing arithmetic. At last the reason why precision raised was simply discussed.