PRF Design And Coherent Integration Detection Technology Of Air Surveillance Radar

When the airborne surveillance radar detects the target of long-range and high-speed,it confronts the problem of range ambiguity and doppler ambiguity.And now the maneuverability of the high-speed target becomes better and better,when the coherent integration of such targets will cause the range rell migration and doppler spread.These problems lead to the information of the target can not be obtained accurately,and the integration and detection performance of the target will be deteriorated seriously.The use of the traditional method of changing the pulse repetition frequency to resolve ambiguity and MTD method to accumulate the target can not solve these problems effectively.Therefore,there is a very important significance in that improving the performance of detecting the airborne flight targets,this thesis has carried out research on this kind of problems,the main research productions include:1.For the problem of range-doppler double ambiguity of target,two kinds of means are proposed by using pulse repetition frequency design combined with signal baseband waveform optimization.The first method is to select and optimize the design of pulse repetition frequency based on the limitation of the working sequence of the space-based radar,and combine the multi-frequency and multi-subband methods to eliminate the range-doppler double ambiguity;the second method is that the doppler frequency of the target is obtained by transmitting the doppler-sensitive and large-time width signal which can ensure that the range is not ambiguity,then using the method that subaperture smoothing and the snapshot processing of non-aperture loss.2.In order to solve the problem of coherent accumulation of high speed and high maneuvering target.first,the echo model of the target is established.Then,the Keystone transform is used in the distance frequency domain-azimuth time domain of echo to correct the range rell migration.Then,the secondary phase compensation function related to the acceleration is obtained,and the acceleration of the phase compensation function is searched by the target covariance value as the objective function,and the acceleration which can get the maximum value of the objective function is the target acceleration.Finally,the acceleration is compensated and the target Doppler broadening problem is corrected.Simulation results show that the proposed method can evaluate the performance of the target effectively.