The Application Of Spatial Super Resolution To Resolve And Orientate Signal In Ship Born OTHR

Ship born OTHR (Over the Horizon Radar) has a wide field of applicationwith good prospects, in ship detection to signal on the ocean. Many countriesinvestigate it as a star. When ship born OTHR detect signal, it should meet thecomplex electronic environment on the ocean. The primal factor is the strong seaclutters. Nowadays the general method to detect and resolve signal in ship bornOTHR is two dimensional FFT. As a result of Bragg scatting, the first order seaclutter conform first order Bragg lines in the echo Doppler frequency spectrum.When the radar platform is statistic, the lines are sharp. The platform motion bringsfirst order sea clutters from different directions towards the receive antenna beampointing, which have different Doppler frequency shifts, the first order Bragg linesare broadened. The broadened Bragg lines will cover the most slow ship targetsdetection region, this makes it impossible to detect and resolve signal from theecho signal Doppler frequency spectrum. The most important issue in ship bornOTHR, is to detect and resolve signal from the broadened first order s ea clutters.Besides the first order sea clutters, the signal detection in ship born OTHR hasto face two technical problem. One is the coherent sources due to the multipatheffect on the ocean. The other problem is the primal noise background constitutedof second order sea clutter and atmosphere noise They will become color noisebetween antenna array elements when they arrive the receiving radar.In this paper, the Doppler frequency of the motivation point target and of thefirst order sea clutters have been deduced from the geometric detection model.From the simulation, the model is correct and the broaden width is changing withthe radar motivation velocity.From the echo signal model, this paper deduced that the echo signal has adifferent direction of arrival from the first order sea clutter in the same Dopplerresolution cell. The echo signal’s spatial spectrum could be obtained by the spatialsuper resolution, from witch the direction of arrival could be obtained, so the echosignal could be detected and resolve from the broadened first order sea clutters.In this paper, firstly spatial super resolution successfully detects and resolvesthe perfect signal in ship born OTHR. Secondly the traditional spatial superresolution can’t detect all the targets and has a huge detection error when the echosignals are coherent and the noise are spatial coherent between the antenna arrayelements. Finally this paper presents forward and back symmetric spatialsmoothing method to resolve this problem, from the simulation, the method iseffect and the target signal could be detected and resolve with a high locationaccuracy and angel resolution power, it has a certain application value and could be used in the real signal detection and resolution in ship born OTHR...