Research On Key Technologies Of Frequency Modulated Continuous Wave Synthetic Aperture Radar High-resolution Imaging

Frequency Modulated Continuous Wave(FMCW) Synthetic Aperture Radar(SAR)is small in size, light in weight, simple in structure, low-cost characteristics suitable forapplication to small unmanned aerial vehicles(UAV) in all-weather, all-time observationand reconnaissance. But for institutional reasons, to achieve high-resolution imaging inhigh-speed, long-distance, large-swath conditions still have many difficulties.This paper focus on the radar system design, we analysis the practical problems inhigh-resolution imaging, and propose specific solutions, including:FMCW SAR system structure、 the principle of high-resolution imaging arediscussed and radar system performance are analyzed. Then put forward to the problemsthat need to be resolved to achieve high-resolution imaging.The effects of sweep nonlinearity on range resolution in FMCW SAR imaging areanalyzed, when transmitted signal is affected by nonlinear, the target energy is spreadfrom different frequencies beat signal after mixing can’t reconstruct the rangeinformation of the target. By analyzing the frequency sweep nonlinearity on the phaseof the difference frequency signal, according to the principle of short time Fouriertransform (STFT), a practical non-linear error compensation method is proposed.FMCW SAR imaging process is discussed. In the traditional “go-stop-go”assumeis established for FMCW SAR two kinds of imaging algorithms are discussed, specificanalysis and process were given.calculated amount and performance indicators areanalysis. The contradiction between the FMCW SAR imaging bandwidth andorientation-dimensional high-resolution is discussed, proposed that use multi-inputmulti-output technology to solve the problem of under-sampling in the low pulserepetition frequency (PRF), combined the MIMO technology and FMCW SAR canachieve the purpose of high-resolution imaging in high-speed, long-distance,large-swath conditions.