Research On Imaging Theory And Technique Of Ultra-wideband Random Noise SAR

Random noise radars have been investigated extensively over the past forty years. They were noted for their attractive LPI (low probability of intercept) and EMC (electro magnetic compatibility). By operating in the low VHF and UHF frequency bands, Ultra wideband synthetic aperture radar (UWB SAR) has been proven to be a very powerful tool that can penetrate the foliage (FOPEN) and ground (GPEN) to detect, image and discriminate the concealed targets. The combination of UWB SAR technology and random noise radar can gain significant benefits and overcome inherent individual drawbacks. Especially, with the increase of serve electronic jamming in modern war and service application, ultra wideband random noise synthetic aperture radar operating in VHF/UHF band could accommodate the complicated military and civil operating environment and creates a wide variety of potential possibilities for applications. The purpose of this thesis is to study the FOPEN/GPEN SAR using UWB random noise signal from theoretical aspect, which is detailed as following:1) Based on the analysis of UWB waveforms: impulse, linear frequency modulated (LFM), step-frequency, random noise, etc., the advantages of random noise are presented. In order to achieve the FOPEN/GPEN, the important system parameters are proposed.2) The principle governing the operation of UWB random noise radar are discussed, with emphasis on the model of random noise radar based on the correlation receiver.3 ) A two-dimension FOPEN/GPEN random noise SAR imaging model is analyzed. Through discussing a typical statistical-physical model for foliage transmission, foliage/ground obscuration impact on SAR images is summarized.4) The unique features for UWB wide angle (WA) SAR imaging are indicated. The adaptive imaging algorithms are investigated and simulated in detail. What's more, as far as UWB/WA random noise SAR is concerned, the predominant WRA (wavefront reconstruction algorithm) is selected to fulfill simulation.At last, the whole thesis is concluded. And future work on the FOPEN/GPEN UWB SAR using random noise signal is pointed out.