Spin Platform 3D SAR Imaging And Height Measurement

Spin aircraft is a kind of aircraft which has the characteristics of high speed, high mobility and spin motion. It is widely used in the area of guidance and trackings. As the radar on this platform difficultly correcte the beam pointing, the platform’s accurate flying height is not easy to get.As the echo phase compensate difficultly, this platform is never as regarded as SAR imaging platform.In this dissertation, by studying a novel model of 3D SAR imaging on the spin platform, a new model of height measurement based on 3D SAR imaging is put forward and software is develped for analysising this model. The main content is:1. This dissertation introduced the single actuator transmit mode of LASAR system, and the 3D spatialambiguity function(AF) is analyzed. Then echo signal model of linear array SAR is established and the 3D spatial resolutions are derived. Finaly, the traditional method of aircraft height measurement is introduced and the advantages and disadvantages of each are put forward.2. 3D SAR imaging model of the spin platform is put forward. Through the analysis of antenna phase center’s trajectory, the half spiral trajectory is equal to the antenna array. Then, based on the equivalent plane array and the fuzzy function theory, a novel spin aircraft 3D SAR imaging model is put forward. By the simulation results, both the the feasibility of this model the factors that influence imaging is validated.3. Spin platform’s height measurement bases on the 3D SAR imaging is put forward. In this model, the platform’s height measurement problem can be converted to imaging problems. Because the height of platform’s sub-satellite point can obtain from 3D SAR imaging, if we get the elevation from the IMU data, the relative height can be measured. Then the factors which affect the precision are analysed. From the simulation results, the effectiveness of the height measurement model and the influencing factors of height measurement are validated.4. The anti-jamming ability of height measurement based on 3D SAR imaging is analyzed. The effect of random noise and frequency domain block distortion on the height measurement is analysised and the simulation experiment proves the conclusion.5. A digital prototype of height measurement based on 3D SAR imaging is developed.Through analyzing the demand of the software, the software is divided into sub modules. Based on the functional requirements of each module, the the feasibility of joint programming of GPU, matlab and VRML is analyzed. Then, the advantages and disadvantages of all kinds of design scheme are taken into consideration. Eventually, the software meets of all user’s needs is designed.This software has the advantages of powerful graphics processing in matlab, the fast parallel processing in GPU, the dynamic exchange scene in VRML.