Preliminary Research On Microwave Staring Correlated Imaging Based On Temporal-Spatial Stochastic Radiation Fields

In this thesis, microwave staring imaging is referred to as an imaging mode through the procedure of radar irradiating unknown targets without the requirement for the relative motion between the radar platform and the targets. The resolution of traditional staring imaging is constrained by the antenna apeture size, objects within the beam coverage can not be resolved. Therefore, in this thesis, we explored and raised a novel microwave staring method to break the resolution limitation and realize super-resolution imaging performance.The reason why the resolution of traditional staring imaging constrained by the antenna apeture size is the lack of variation of the difference in the radiation field within the beam. In traditional staring imaging, the spatial distribution of the radiation field of different time preserves uniformity, so we can construct only single independent observation function to obtain the information of the imaging area. However, by constructing more independent observation functions through the design of temporal-spatial stochastic radiation fields, we can get extra more information of the objects within the beam. According to this inspiration, we proposed the novel microwave staring correlated imaging system based on the temporal-spatial stochastic radiation fields. The observations of different time may be overlapped, so we should correlate the temporal-spatial stochastic radiation fields with the echo to realize the extraction and separation of the information of the object, therefore radar imaging breaking the limitation by the aperture size is finally achieved. In the end of chapter two, we derived and analysed the performance of microwave staring correlated imaging system under ideal temporal-spatial stochastic radiation fields, and trhough the simulation we verified the practicability of the novel method we proposed.The variation of the difference in the radiation field is key to microwave staring correlated imaging. It can not only determin the imaging resolution in the succedent correlated process, but is also the accordance of the radiator design in microwave staring correlated imaging, the thesis is preliminarily unfolded focusing on this topic.Chapter three mainly discuss the relationship of the variation of the difference in the radiation field and statistical characteristic of the aperture field. In the simulation the spatial coherence of the radiation field and the rank of the radiation observing matrix is obtained under the conditions of different parameters. Chapter four first dirived the effective extraction method of the object information in microwave staring correlated imaging, and then redefined the resolution from the viewpoint of the matrix equations and the imaging system respectively. The two redefinition of the resolution is equivalent. From the viewpoint of the matrix equations, we defined the resolution using the independent radiation samples as the intermediate quantity in microwave staring correlated imaging. From the viewpoint of the imaging system, we proposed a novel resolution concept that incorporates both the main lobe and the side lobe of the PSF.Chapter five analysed the impact of the synchronization error on microwave staring correlated imaging aimimg at the problem of the high precision requirement of time synchoronization and the transient changes of the radiation fields. Based on the idea of time-sharing accumulation, a novel imaging method requiring much lower precision of time synchronization is proposed.