L频段星载SAR与GNSS同频干扰分析及验证

Analysis and Verification of Co-frequency Interference Between L-band Space-borne SAR and GNSS

针对L频段合成孔径雷达(SAR)卫星大功率载荷和高灵敏度双频导航接收机同时工作时潜在的同频干扰问题,基于某型SAR卫星,开展了SAR与全球导航卫星系统(GNSS)星内、星地同频干扰分析及实物验证。星内同频干扰分析,表明星内存在较为严重的同频干扰问题,需要采用在导航接收机前端,增加随SAR载荷发射脉冲信号联动工作的电子微波开关的抗干扰抑制措施。利用实物在暗室无线环境下,完成了干扰措施有效性验证,导航原始数据分析结果表明,措施有效且简单易行;针对星地同频干扰,由于SAR载荷合成孔径、低占空比脉冲工作的特点,使得地面GNSS接收机能够被SAR载荷照射的时间很短、照射概率很低,且照射强度也低于接收机的饱和电平,预期不会对接收机造成影响。

Aiming at the problem of potential co-frequency interference when the high-power SAR payload and the high-sensitivity receiving dual-frequency navigation receiver work at the same time,analysis and physical verification of SAR and GNSS intra-satellite and satellite-ground co-frequency interference are carried out based on a certain SAR satellite.The analysis results of intra-satellite co-frequency interference show that there is a serious problem of co-frequency interference on board.It is necessary to adopt anti-interference suppression measures by adding electronic microwave switches working in conjunction with SAR load emission pulse signals at the front end of the navigation receiver.The effectiveness of interference measures is verified physically in the darkroom wireless environment.Analysis results of the original navigation data show that the applied measures are effective and simple.Satellite-to-ground co-frequency interference analysis results show that the SAR payload has the characteristics of synthetic aperture and low duty cycle pulse operation,so that the ground GNSS receiver can be irradiated by the SAR payload for a short time,with low irradiation probability,and the irradiation intensity is also lower than the saturation level of the receiver,which will not affect the receiver.