星载双基地SAR系统模糊性

Ambiguity in Spaceborne Bistatic SAR

针对星载双基地SAR由双基地几何关系引入的新问题,提出了计算其模糊比的新方法和近似分解方法。利用此方法通过仿真计算对星载双基地SAR模糊性变化规律做了进一步研究。结果表明,因接收天线的面积限制,与其伴随飞行的大卫星SAR相比,模糊性问题更为严重,但变化规律基本一致。比较而言,由于小卫星天线尺寸在高度上更接近大卫星天线,在距离模糊比上相对大卫星SAR抬高得不多,而在方位模糊比上抬高较大。

A new method for evaluation of ambiguity-to-signal ratio in spacebome bistafic SAR was proposed in terms of bistatic geometry. Based on that, the ASR of the new system was analyzed in different cases. Simulation results show that due to the limited size of antenna onboard small satellite, the ASR of bistatic SAR is much bigher than that of monostatic spacebome SAR, though their changing trends are similar. Compared with the ASR in azimuth, the ASR in range is closer to that of the monostatic case because the size in height dimension of small antenna is closer to that of the big antenna than the length dimension is.