在振动环境下相位噪声对星机BiSAR的影响

Impact of Oscillator Phase Noise on Spaceborne-Airborne BiSAR Under Vibration Perturbing

振荡器的相位噪声是影响BiSAR获得高分辨率图像的重要因素之一。振荡器是一种对振动极为敏感的器件。因此,在振动环境下,定量分析相位噪声对BiSAR的影响是十分必要的。文中基于两个独立非同分布的振荡器,机载SAR在静态条件和随机振动环境下,推导了星载-机载混合BiSAR(SA-BiSAR)积分旁瓣比的计算公式。仿真结果表明,在静态条件下,SA-BiSAR仍然具有很低的相噪谱;机载SAR在振动环境下,对于L波段,可以满足成像的基本要求;对于X波段,需采取必要的隔振措施提高系统的抗振性能来满足成像的条件。

Oscillator phase noise impacts BiSAR image quality, and oscillator is an apparatus sensitive to vibration. In this paper, based on independent and non-identical distribution oscillators, the formula of integration sidelobe ratio of spaceborne-airborne hybrid BiSAR is derived when airborne SAR is at static condition or perturbed by random vibration. The simulation results show that SA-BiSAR has very low phase noise spectrum when airborne SAR is at static condition, but the SA-BiSAR image quality is affected by random vi- bration. Without separating vibration, the basic requirement of SAR imaging is satisfied for L-band. However, vibration separating measures are needed for X-band in order to satisfy the conditions of SAR imaging.