基于双调频斜率的分布式星载雷达波形设计

在分布式星载雷达系统中，为了获得分集增益和高分辨性能，要求各雷达发射的波形具有较强的正交性和较低的多普勒敏感性.通过对双调频斜率(Double Frequency Slope，DFS)信号的自相关性、距离分辨率、互相关性以及多普勒容忍性等性能的研究，推导出该波形各参数之间的关系.在此基础上，结合分布式星载雷达系统的要求提出了基于DFS信号的波形参数设计方法，并设计出具有正交性和低多普勒敏感性的DFS信号波形.研究结果表明：在信号时宽不变的情况下，增大各子信号间的调频斜率差可以提高多个DFS波形间的正交性；而要使DFS波形具有较低的多普勒敏感性，则可以通过增大信号带宽或减小调频斜率差来达到.仿真结果表明：利用波形参数间的相互关系设计出的DFS信号波形，能够较好地满足分布式星载雷达系统的要求.

Waveform design based on double frequency modulation slope for distributed space-borne radar system

In order to obtain diversity gain and achieve good resolution performance, distributed space-borne radar system requires transmitting orthogonal waveforms with low Doppler sensitivity.The relation between parameters of double frequency slope (DFS) waveform is deduced after studying the performance of autocorrelation, range resolution, cross-correlation and Doppler sensitivity.Then, a waveform parameters designing method of DFS waveform is proposed according to the requirement of distributed space-borne radar system, and the DFS waveform with good orthogonal performance and low Doppler sensitivity is designed.It is indicated that on the condition of the pulsewidth unchanged, the orthogonal performance of DFS waveforms gradually enhanced with the increase of the differences of frequency slope between sub-signals, and the low Doppler sensitivity performance can be reached by increasing the signal bandwidth and decreasing the differences of frequency slope.The simulation results show that the DFS waveform designed by the proposed method can meet the requirement of distributed spaceborne radar system well.