The Study On Imaging Technology Of One-stationary Bistatic Low Frequency UWB SAR

One-stationary bistatic low frequency synthetic aperture radar(OS LF UWB BiSAR) is an UWB SAR system which has a moving transmitter(or receiver) and a stationary receiver(or transmitter). Compared to the monostatic SAR, it brings several additional benefits like increased reliability and flexibility of future SAR missions, remarkable foliage penetrability, and reduced vulnerability for military applications. Thus, OS LF UWB BiSAR has gained wide attention these years.This dissertation has carried out four subjects of OS LF UWB BiSAR: system characteristics, imaging algorithm, motion compensation and synchronization techniques.In system characteristics analysis, the geometry model and the echo model are established. And the range history, coupling peculiarity and spatial resolution of this radar system are analyzed. Thus the theory foundation for further research is established.In study of frequency imaging algorithm, the range-doppler spectrum of point target response of OS LF UWB BiSAR: is derived firstly. And then, the Non-Linear Chirp Scaling(NLCS) imaging algorithm is investigated, and the imaging effect of the higher order phase error, which is due to the Taylor series approximation conducted by NLCS algorithm, is analyzed. At last, a modified method based on higher order phase compensation(HOPC) and block processing is proposed to deal with the HOPEIn study of motion compensation, firstly the motion error model of OS LF UWB BiSAR is established, and the main components of motion errors are analyzed. Then based on the classical motion compensation method, a motion compensation method combined with NLCS algorithm is proposed. At last, a motion compensation method based on NUFFT is carried out for the forward velocity error.In study of synchronization technique, the time synchronization problem in One-stationary bistatic LF UWB SAR system is analyzed firstly. The expression for the impact of time synchronization error is derived and the quantitative indicators is given. Then the frequency synchronization problem is studied, the model of frequency synchronization error was established and the effect of which is analyzed. At last, the time and frequency synchronization method based on GPS signal is investigated by an experiment.