Study On The Electromagnetic Damage Effect Of Lightning Strike On Airborne Autonomous Navigation System

This paper focuses on the electromagnetic damage effect of lightning on the airborne autonomous navigation system.Taking the UAV airborne navigation system as the research object,using the methods of theoretical analysis,electromagnetic simulation and experimental research,the typical lightning electromagnetic environment analysis,lightning effect simulation,lightning surge injection test,electromagnetic damage analysis and protection methods of devices are carried out,and the damage threshold,damage process,vulnerable components,damage mode,damage mechanism and protection method of each port of airborne autonomous navigation system components are obtained.Firstly,the analysis of lightning electromagnetic environment is carried out,and the results show that component A(first return stroke current)of lightning current can more comprehensively evaluate the electromagnetic damage effect of UAV suffered from lightning in terms of intensity and influence degree.The coupling way of lightning electromagnetic energy is determined.Lightning electromagnetic pulse mainly damages the airborne autonomous navigation system through the shell and transmission line.Based on the analysis of lightning electromagnetic environment and the characteristics of target,the simulation of lightning effect is carried out.The results show that the electromagnetic field intensity inside and outside the UAV is very strong at the moment of lightning strike,and the change trend is consistent with the lightning current.Under the shielding effect of the shell,the energy of lightning electromagnetic pulse is greatly attenuated,which can not effectively damage the navigation system.The three types of cable placement have little effect on the waveform trend of induced voltage.The maximum value of electromagnetic induction voltage is 646 V,which will damage the autonomous navigation system.According to the simulation research of lightning effect and the standard RTCA-DO-160 G,the W4 voltage waveform with peak time and half peak time consistent with the cable coupling simulation results is selected to carry out lightning surge injection test on each port of the key modules of the autonomous navigation system: GPS module and inertial sensor module.The results show that the damage threshold of each port is between 40.7V and 582.6V,which is lower than the peak value of cable coupling simulation voltage.With the damage of GPS module from transient to permanent,the function of GPS module is enhanced.For the inertial sensor module,the vulnerable components are the near end capacitance of each port and various amplifiers.Finally,the electromagnetic damage analysis and protection methods are studied.The research shows that the damage of capacitor is caused by high voltage breakdown,and the failure mechanism of damaged device is dielectric layer breakdown under high voltage and metallization burning under high current impact.The transient suppression diodes are paralleled between each port and the ground,which can realize the basic lightning protection.The research results of this paper provide ideas and methods for the study of lightning electromagnetic damage effect of airborne autonomous navigation system.