Research On Astronomical Satellite ToO Planning Under Tiling Coverage Strategy

Gravitational wave is the ripple of space-time.In 1916,Einstein predicted the existence of gravitational wave based on general relativity.The study of gravitational wave can make human better understand quantum gravity,space-time structure and cosmic mystery.The observation of gravitational wave events has become an important direction of modern space science research,and is a frontier topic in the future science field.On August 17,2017,the US gravitational wave probe LIGO and the Italian gravitational wave probe Virgo jointly detected the gravitational wave event gw170817.In the following seconds,NASA's Fermi satellite and ESA's integral satellite detected a very weak short-term gamma storm.This is the first time in human history that gravitational wave and electromagnetic wave are used to observe the same astrophysical event at the same time,which marks the beginning of a new era of multi-messenger astronomy.Astronomical observation plays an important role in space science exploration and research.The target of opportunity(ToO)in space,including gravitational wave(GW),gamma ray burst(GRB)and so on.It is an important function of the mission planning system to generate the observation plan of ToO,especially the gravitational wave event.Due to the characteristics of high timeliness,the diversity of requirements and the complexity of constraints,the quick response of the mission planning system is needed to obtain higher scientific observation benefits.According to the requirements of practical engineering tasks,this paper studies the mission planning method of astronomical satellite ToO under tiling coverage strategy.Firstly,the modeling and solving algorithms of domestic and foreign experts in the field of satellite mission planning are investigated.The characteristics of astronomical satellites ToO mission planning under tiling coverage strategy are analyzed.The mathematical modeling and algorithm design for this research are carried out.The experiments and results are analyzed.Finally,based on the above algorithm,optimization and improvement are made.The main work and innovation of this paper are as follows:(1)Analysis and Mathematical Modeling of Astronomical Satellite ToO Planning under Tiling Coverage StrategyThe scenario and demand of the planning problem is analyzed,the problems of the astronomical satellite ToO planning under tiling coverage strategy is described.The complex problems are abstracted and simplified,and the basic assumptions are given in combination with the actual situation to complete the establishment of the mathematical model.(2)Design Algorithm and Optimized Algorithm for Astronomical Satellite ToO Planning under Tiling Coverage Strategy,Verify and Analyze the Algorithm by SimulationTwo algorithms are designed,which are Rule Based-Tiling-TPA and GA-Tiling TPA.The experimental results show that both algorithms can give the planning result that meets the planning requirements,but the convergence speed of GA-Tiling TPA is far less than that of Rule Based-Tiling-TPA.Rule Based-Tiling-TPA needs heuristic function designers to have certain experience and knowledge requirements and strong pertinence;GA-Tiling TPA has strong advantages and strong expansibility in the face of the optimization problem that the feasible solution grows exponentially with the scale.(3)Algorithms are Combined to Optimization DesigningIn order to solve the problem of slow convergence speed of GA-Tiling TPA,the algorithm is optimized from the aspect of initialization population.The Rule Based-Tiling-TPA and the GA-Tiling TPA are combined.The planning results of the former are used as the initialization input of the latter.This scheme greatly improves the convergence speed of GA-Tiling TPA.GA-Tiling TPA has ability to jump out of the local optimal solution,the improved algorithm can generate better planning results.