Model and signal processing of bistatic frequency-modulated continuous wave synthetic aperture radar

Abstract

Bistatic frequency-modulated continuous wave (FMCW) synthetic aperture radar (SAR) mounts the radar transmitter and receiver on separate platforms, which offers considerable capabilities, reliability and flexibility in designing FMCW SAR missions. Moreover, the spatial separation achieves better isolation between transmission and reception channels compared with the monostatic FMCW SAR where the two separate dedicated antennas are fixed on one platform. In this study, a bistatic FMCW SAR signal model is proposed to formulate the bistatic slant range history in bistatic FMCW configuration. Based on the preceding model, an approach is presented to deal with the double-square-root (DSR) term, and thus an accurate FMCW bistatic point target reference spectrum (BPTRS) is derived. Besides accurately addressing the signal characteristics of bistatic FMCW SAR, the proposed spectrum also significantly simplifies the signal processing of bistatic FMCW SAR, which will really push the applications of bistatic FMCW SAR in remote sensing fields. Furthermore, based on the proposed BPTRS, an extended inverse chirp-Z transform (EICZT) algorithm is proposed to process the bistatic FMCW SAR data by introducing a perturbation function to deal with the range-variance of second-and third-order range-azimuth coupling terms. Two simulation experiments are carried out to verify the accuracy of this novel formulation and highlight the performance of the proposed focusing approach.

Reconstruction of uniformly sampled signals from non‐uniform short samples in fractional Fourier domain

“…A high-resolution wide-swath image with a mini-sized system is becoming more important in military monitoring and small-scale earth observation applications. As one of the new radar systems, the FMCW SAR offers a lightweight, high-resolution and cost-effective imaging sensor of high resolution [28][29][30]. Moreover, high-resolution and wide-swath SAR images can be obtained by multichannel sampling.…”

A Bistatic Imaging Method for GEOSAR in the Strip Mode and UAVSAR in the Steering Beam Mode

“…For the short synthetic aperture time of this bistatic radar, GEOSAR on the small orbital inclination (≤5°) may be approximately considered a static situation, and only the receiver contributes to the all azimuth modulations [4,5]. The classical bistatic imaging algorithm cannot be employed to carry out this radar echo signal [6][7][8][9]. The imaging algorithm deals well with the data from the stationary transmitter and airborne receiver in the various working modes [10].…”

Focusing Bistatic FMCW SAR Signal by Range Migration Algorithm Based on Fresnel Approximation

“…Bistatic configuration provides a possibility to significantly increase the antennas space isolation while still keeping the small size of the radar. The two-dimensional spectrum of bistatic FMCW SAR has been researched in [ 12 , 13 ]. In [ 12 ], an approximated slant range equation is used to express the demodulated signal.…”

“…The two-dimensional spectrum of bistatic FMCW SAR has been researched in [ 12 , 13 ]. In [ 12 ], an approximated slant range equation is used to express the demodulated signal. The spectrum is then obtained by treating the azimuth frequency as two parts caused by transmitter and receiver separately.…”