| Spaceborne InSAR is a high-precision InSAR technology.Compared to the airborne InSAR system,the ground observation is performed on a higher and more stable platform,which can work in where the aircraft cannot observe.What's more,the coverage is wider;the global digital elevation model(DEM)is established in an all-time,all-weather way,so it plays an important role in various fields such as topographic mapping,military operations,and economic construction.In various types of spaceborne InSAR systems,the dual-antenna InSAR system is a single-pass InSAR system,extending two antenna arms from the satellite to form a very stable interference baseline.SAR images are used for interference,and it can overcome the inherent defects of various decoherent sources compared to multi-pass systems.At the same time,the stable interference baseline also makes the interference mapping quicker,and obtains more complete observation data.On the contrary,the complexity of the satellite structure,the limitation of the baseline length,and the influence of the vibration of the antenna arm will bring considerable errors to the SAR interferometry,and there is no on-board dual-antenna InSAR systems used as reference.A more sophisticated predictive analysis of the performance of the system also requires a more comprehensive analysis of the error.In this paper,the characteristics of the spaceborne dual-antenna InSAR system are studied to improve the performance of the spaceborne dual-antenna InSAR system.The system error analysis,signal simulation,performance improvement technology and antenna mast motion are studied in depth.The main work of the paper is summarized as follows:The first chapter is an introduction,which mainly describes the background and research significance.It summarizes the research status of the spaceborne dual-antenna InSAR from three aspects: performance analysis,signal simulation and antenna arm influence.At the same time,the full text frame is introduced.The second chapter mainly introduces the performance analysis and simulation of the dual-antenna InSAR system.The SAR imaging performance analysis model and InSAR altitude measurement model of dual-antenna InSAR system are established.The simulation method of spaceborne dual-antenna InSAR system is also presented,and the signal simulation of the model is realized..The third chapter studies the dual antenna InSAR alternating.bistatic mode.The principle of alternating.bistatic mode in dual-antenna InSAR system is studied.The performance analysis model of alternating.bistatic mode is given.It analyzes the performance of alternating bistatic mode.The simulation results show that the alternating bistatic mode's performance is nearly the double of bistatic mode's.The fourth chapter focuses on the influence of the antenna mast motion of the spaceborne dual-antenna system on the InSAR height measurement.The antenna mast motion is divided into low-frequency motion and high-frequency motion.The antenna mast motion high-low frequency determination model is established,and the motion amplitude is analyzed.It establishes the antenna mast motion amplitude threshold model is.Finally,a series of simulation experiments prove the correctness of each model.The analysis of the influence of dual antenna motion in InSAR is more comprehensive.At the same time,the InSAR altimetry with high frequency motion of the antenna mast is simulated,which provides theoretical support for eliminating the high frequency vibration error of the antenna arm.The final chapter is a summary and outlook.It outlines the work content and innovation of the whole article,conceives and plans for the future research content.The research in this paper has important theoretical and practical value for realizing the optimization and high-precision data processing of the spaceborne dual-antenna InSAR system. |
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