Study on Motion compensation for airborne forward looking array SAR by time division multiplexing receiving

Combined with Frequency-Modulated Continuous-Wave (FMCW) technology, airborne forward-looking array synthetic aperture radar (SAR) can obtain the image in front of the aircraft and also have the advantages of FMCW radar such as small size and lightweight. Moreover, it is suitable to be installed on platforms like helicopter and small unmanned aerial vehicle. To reduce the complexity of the hardware system, it is sensible to make the linear array antennas work in the time division multiplexing receiving mode. Motion compensation for forward-looking array SAR in this mode is one of the key problems to obtain the image in front of the aircraft in practice. This paper analyses the influence of motion error in aircraft on echo model based on the geometry of forward looking array SAR and proposes a motion compensation scheme. Moreover, the compensation scheme is applicable to an improved frequency scaling algorithm (FSA) for FMCW forward looking array SAR. Finally, the compensation scheme is verified with the simulation.