Research On Active Cancellation Technology Of Radiation Interference On Complex Platform

With high-power electromagnetic-jamming equipment developing and the equipment integrated on the same platform increasing,receiver with high sensitivity tends to be disturbed or even saturated,which the satellite navigation receiver is a typical example.Because the navigation signal is weak,and the gain of the receiver is relatively high,the channel is prone to be saturated.When the interference signal power at same frequency is too large,the IF anti-interference algorithm will not solve the signal distortion caused by channel saturation.Signals beyond bandwidth can be cancelled through the filter,but the same frequency interference can not be eliminated.Therefore,it is very important to analyze the interference of high sensitivity frequency equipment,and solve the electromagnetic compatibility problem of anti-saturation interference.In this paper,the coupling between antennas on the platform and the feasibility of interference cancellation is simulated and analyzed.The dynamic range of the system and the initial weight range are determined at the same time.According to the situation of interference,the method of multi-channel cancellation is chosen to resist interference.The basic principle of the common adaptive array processing method and the antijamming beam forming method are studied,and the performance of each algorithm is simulated and verified.The specific problems of multi-channel anti-saturation interference method are analyzed,and the corresponding solutions to these problems are put forward.Aiming at the problem of feasibility and error,this paper proves the uniformity of RF and IF weighting,and proposes a correction method which can solve the inconsistency of channels and the nonlinear error of the vector modulator at once.For eliminating of multipath interference,analyzes the feasibility of space-time adaptive anti-interference algorithm,proposes a method of bypass delay elimination on the same platform,and introduces the design of interference reference source.For the problem of LMS algorithm step design,the performance of algorithm and step selection simulation and analysis is carried out,and step adaptive adjustment method is showed.For the problem of mutual coupling of antenna array element,this paper simulates analysis of the impact of mutual coupling on interference performance,and proposes an adaptive calibration method based on LMS algorithm.Finally,the overall scheme of the system is demonstrated,with the hardware circuit design and algorithm implementation.The anti-jamming performance of the system is tested from the aspects of anti saturation ability,interference suppression ratio,the number of anti-multipath interference,the system response time and so on.The anti-jamming performance of GPS receiver board is simulated and analyzed under the strong interference as practical application.