Research On Resource Scheduling Technology Of Tracking And Data Relay Satellite System

Tracking and Data Relay Satellite System(TDRSS),referred to as relay satellite system,is composed of ground stations,user spacecrafts,and relay satellites on the geosynchronous orbit.As a core of space-based TT&C(telemetry,tracking and control)system,TDRSS can not only solve the high coverage problem of TT&C and communication in the satellite communications,but also satisfy the technical requirments of high data transmission and multi-target TT&C.Therefore,TDRSS has wide application prospect in the field of aerospace.Relay satellite resource scheduling is one of the key technologies of relay satellite system.Along with the rapid development of aerospace industry,the number of user spacecrafts increases rapidly.However,the number of relay satellites remains limited.The corresponding time resources,frequency resources and power resources are not sufficient.Hence,a variety of tasks requests,user spacecrafts data transmission can not be fully satisfied.In a relay satellite system comprising a large number of user spacecrafts,the research on the relay satellite resource scheduling technology can give full play to the TT&C and tracking functions of relay satellite,and ensure the efficient operation of the relay satellite syst em.Therefore,the research in this dissertation focuses on the relay satellite resource scheduling technology,and contains three parts of research contents,which are single access link static resource scheduling of TDRSS,single access link dynamic resource scheduling of TDRSS and multiple access link resource scheduling of TDRSS.Firstly,single access link static resource scheduling of TDRSS is researched.In the case of single access link,the relay satellite can only handle one task proposed by user spacecraft at the same time.Based on the analysis of the characteristics and constraints of the resource scheduling problem,the mathematical model for the single access link static scheduling of TDRSS is eatablished,in which several visible time windows are taken into account.Then the artificial bee colony(ABC)based single access link static resource scheduling algorithm is proposed.The perfomance of proposed algorithm is simulated by comparing with other three kinds of intelligent optimization algorithms.With the overall consideration of optimization ability and the convergence,the proposed algorithm is able to obtain more scheduling profit with faster convergence speed.Secondly,single access link dynamic resource scheduling of TDRSS is researched.After the generation of the initial static relay satellite resource scheduling scheme,the initial scheduling scheme cannot be implemented immediately.In this period,the tasks set would be changed dynamically,which leads to the result that the initial static scheme can not be applied to the post disturbance scheduling model.The dynamic scheduling scheme not only aims at maximizing the scheduled tasks priority sum,but also minimizes the variation between the initial scheme and the dynamic scheme.Therefore,the corresponding resource scheduling model is a multiple criteria decision making problem.By the given definition of schemes variation,the dynamic resource scheduling problem is considered as a multiple attribute decision making(MADM)problem.The dynamic resource scheduling algorithm based on attribute ranking and technique for order preference by similarity to ideal solution(AR-TOPSIS)is proposed.Moreover,the scheduling scheme cost index is introduced to measure the two attributes of the total priority and the schemes variation in a unified way.The simulation results show that the proposed algorithm gets superior performance.The obtained dynamic scheduling scheme achieves higher total priority at the expense of smaller schemes variation,and the proposed algorithm is suitable to solve the dynamic relay satellite resource scheduling problem.Lastly,multiple access link resource scheduling of TDRSS is researched.Resource scheduling problem of TDRSS in the traditional code division multiple access(CDMA)system is analyzed,and tasks parallel constraint detection based scheduling algorithm is proposed.Since TDRSS is a multi-user satellite communication system,if orthogonal frequency division multiple access(OFDMA)technique is introduced into the relay satellite system,it can assign different subcarriers and system power to users according to the requirements of data rate.The mathematical model of rate adaptive(RA)based resource allocation with proportional fairness constraints is established.Then an efficient resource allocation algorithm is proposed,which based on ant colony optimization subcarrier allocation(ACOSCA)and suboptimal power allocation(SPA).In reference of ACO algorithm for solving traveling salesman problem,the ACO based subcarrier allocation algorithm is proposed and the Jain's fairness index is introduced into the heuristic information in ant's transition probability.In order to strictly satisfy the proportional fairness,a suboptimal power allocation principle is proposed.In the simulation results,the performance of proposed algorithm is put in contrast with the other two approaches.The proposed algorithm achieves higher sum rate in the same situation than the other two algorithms.In addition,strictly proportional fairness is obtained.