摘要
在中轨合成孔径雷达(synthetic aperture radar,SAR)成像中,大斜视角以及长合成孔径时间会导致信号产生严重的距离走动和二维空变。首先,针对信号的距离走动问题,采用了变脉冲重复频率(pulse repetition frequency,PRF)技术对回波进行录取,消除大距离走动带来的回波接收问题。然后,针对传统的波数域算法不能实现大斜视中轨SAR信号的聚焦问题,提出了一种结合改进的Stolt插值的时频联合尺度变换的成像方法,利用方位时间尺度变换来解决信号方位调频率的2次空变,再使用改进的Stolt插值完成距离徙动校正。最后,利用多普勒尺度变换来处理剩余的高次空变。通过仿真结果可以证明所提算法的有效性。
The squinted observation geometry along with long integration time significantly increases the space variance of the medium-Earth-orbit SAR signal.Firstly,in order to solve the range walk of the signal,a variable pulse repetition frequency(PRF)technology was used to receive the echos.Variable pulse repetition frequency is recommended to handle the severe range walk.The existing wavenumber algorithms cannot handle the nonlinear and range-azimuth-coupled space variance over a large scene.We propose a modified Stolt mapping method along with a modified joint time and Doppler scaling for imaging.An azimuth time scale transformation is used to deal with the quadratic space variance of the azimuth frequency modulation rate.A modified Stolt mapping is used to correct range cell migration.To address the range-azimuth-coupled space variance,the Doppler linearization is done in the range-Doppler domain using range-dependent Doppler scale transformation.Simulation results are shown to verify the effectiveness of the developed focusing approaches.
作者
陈权
孙光才
刘文康
邢孟道
CHEN Quan;SUN Guangcai;LIU Wenkang;XING Mengdao(National Lab of Radar Signal Processing, Xidian University, Xi’an 710071, China;Collaborative Innovation Center of Information Sensing and Understand, Xidian University, Xi’an 710071, China)
出处
《系统工程与电子技术》
EI
CSCD
北大核心
2020年第2期309-314,共6页
Systems Engineering and Electronics
基金
国家重点研发计划(2017YFC1405600)
国家自然科学基金创新群体基金号(61621005)
中央高校基本业务费(JB180213)资助课题
关键词
中轨SAR
二维空变
变PRF
时频联合尺度变换
medium-Earth-orbit(MEO)SAR
2-D space variance
variable pulse repetition frequency(PRF)
joint time-frequency scale transformation
