On-board Autonomous Time Calibration Method Based on Lunar Occultation Obsercations
The autonomous planning and scheduling of the satellite is highly dependent on In re-sponse to the dependence of existing autonomous mission planning and navigation on the accuracy of the on-board clock,as well as the current situation where satellites widely needs to be calibra-ted by the external information such as Global Navigation Satellite System(GNSS)or ground time service system.This paper proposes a method to measure Lunar Occultation using on-board attitude sensor,retrieve the exact time of occultation according to the on-board high-precision star catalogue,and then correct the on-board clock to provide a high precision time reference for autonomous navigation and autonomous mission planning.Firstly,the time series of occultation events and the least square algorithm for the deviation of observation time are deduced,and the calculation method of time checking correction based on genetic algorithm is proposed.Secondly,the detectability of occultation events is simulated and analyzed.Finally,the effectiveness of the on-board autonomous time calibration simulation system based on genetic algorithm is verified by simulation.The simulation results show that the clock calibration method is effective and feasi-ble,and the deviation is better than 0.005s,which can be used as a backup means for satellite calibration in projects such as micro-satellite and deep space exploration.
lunar occultationtime seriesleast square algorithmgenetic algorithmon-board au-tonomous time calibration
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