| 1. | The study background of the low frequency uwb - sar is given in chapter 1 . the sar calibration hierarchy model is proposed , and the calibration concepts and strategies are discussed clearly 第一章分析了低频uwb - sar的研究背景,提出了一种sar层次化校准模型,较为清晰地论述了sar校准概念和策略。 |