Constellation Design Of LEO Satellite Communication And Navigation Fusion

With the advent of the "unmanned era" such as autonomous driving,smart agriculture,and robots,the demand for high-precision positioning,high-capacity and low-latency communications continues to increase.The high GNSS orbital altitude,slow changes in constellation geometry and low signal landing power restrict the application of high-precision positioning,navigation,and timing.At present,satellite communication constellation systems are mainly distributed on MEO and GEO,their large communication delay and small system capacity cannot meet the low-latency and highspeed communication requirements required by the unmanned era anytime and anywhere.LEO constellations have low working orbit altitudes,rapid geometric configuration changes,large constellations,large communication bandwidths and high speeds,which make them an important development direction for satellite navigation and satellite communications.LEO constellation design,which requires comprehensive consideration of system service performance,cost and other factors is the basic prerequisite for system construction.According to the development needs of satellite navigation and satellite communications,this paper conducts research on LEO constellation design optimization technology.The main work and innovations are as follows:(1)A LEO hybrid constellation optimization design method based on the combination of satisfaction function and genetic algorithm is proposed.Utilizing the feature that hybrid constellation’s satellite arrangement in space can be flexibly adjusted,the characteristics of the satellite arrangement in space,the proposed algorithm use physical programming method as evaluation criterion and considers the objective of uniform global coverage to design and optimize WS/WD,WD/WD and RS/RS constellation while comparing with WS constellation.The simulation results show that when the number of satellites in the constellation is 200,the coverage uniformity of the WS/WD,WD/WD and RS/RS mixed constellation is 85.94%,89.26% and 87.40% better than that of the single WS constellation.The satisfaction of its comprehensive optimization objective is 82.22%,84.44% and 85.19% better than that of the WS constellation.(2)A design method of LEO navigation constellation based on mixed integer ANSGA-III is proposed.In view of the problem that the quality of the Pareto solution set is prone to decrease in the design of the LEO constellation,the adaptive population diversity maintenance mechanism of the A-NSGA-III algorithm is used to improve the quality of the Pareto solution set.The simulation results show that when the total number of satellites is restricted to 200,compared with the traditional NSGA-III design method,the average GDOP of the WS/WD,WD/WD and RS/RS constellations optimized by this method is reduced by 68.49%,86.90% and 43.40%,respectively.(3)A design method of LEO communication and navigation fusion constellation considering user distribution model is proposed.According to the global user distribution characteristics,combined with the relationship between LEO satellite coverage and communication capacity,the algorithm comprehensively consider user distribution,communication capacity,and navigation service performance to design and optimize the communication and navigation fusion constellation.The simulation results show that when the number of satellites in the constellation is close,the LEO constellation optimized for communication and navigation integration has improved 35.42% and 25.09%in the average GDOP compared with the communication-only LEO constellation corresponding to a minimum communication capacity of 50 Mbps and 100 Mbps,respectively.