Study On Low-speed Target Detection And Location Technology For UAV Airborne Multi-channel PD Radar

Compared with the common single channel radar,the airborne multi-channel radar has significant advantages in detecting and locating low-speed moving targets.Taking the three-channel radar as the representative,the detection and location of low speed moving targets for multi-channel radar is studied in this paper.Based on the measured data and simulation data,the complete process of airborne multi-channel radar,including motion compensation,clutter suppression,target detection and location,etc.,is analyzed in detail.Motion compensation directly affects the accuracy of subsequent detection and location.However,the non-stationary nature of the actual scene can't fully satisfy the premise of the correlation function method.For this reason,an improved carrier motion compensation method is proposed in this paper,which can get more accurate results of the Doppler center frequency estimation.In addition,an improved quasi Newton likelihood method is proposed in the location process,which effectively solves the problem of slow converging velocity and low accuracy in quasi Newton likelihood method.The experiments on radar data demonstrate the effectiveness of the propose method in reducing the number of iterations,improving the convergence speed,and improving the positioning accuracy to a certain extent.The main work is as follows:1.The target detection and location are based on the motion compensation of the carrier.Therefore,the motion compensation of the carrier has great influence on the accuracy of the angle measurement.A modified Doppler center frequency estimation method is proposed to achieve more accurate estimation of the Doppler center frequency in view of the fact that the stability of the scene cannot fully satisfy the correlation function method.The effective motion compensation processing of aircraft carries the foundation for improving the accuracy of target detection and location.The effectiveness of the improved method is verified with the measured data,and the effect of different motion compensation methods are compared and analyzed.2.Low speed target signal and the main clutter region have a close distance in the clutter spectrum,which brings a great problem to the detection and location of the low speed target.At the same time,the SCNR further affects the accuracy of the target detection and location,so it's of great significant to study the clutter suppression method.Based on the measured and simulated data,different clutter suppression methods are compared,the influence of the clutter suppression process on the target signal is analyzed,the robustness of different clutter suppression methods is compared.In addition,we study the relationship between the array error and the STAP performance,and discuss the influence of the heterozygosity ratio on the localization method.3.On the basis of carrier motion compensation and clutter suppression,an improved quasi Newton maximum likelihood method is proposed based on the quasi Newton maximum likelihood method.When the improved algorithm is equivalent to that of the original algorithm,the number of iterations needed to achieve convergence is reduced to about 1/3.The accuracy of target angle measurement varied with the actual factor,e.g.SCNR,is tested.