Research On Satellite-Ground Station Data Transmission Scheduling Models And Algorithms

Satellite data transmission scheduling problem (SDTSP) is assigning limited ground station resources for satellite data transmission requests (SDTR) reasonably. In this paper, scheduling models and its algorithms of STDSP are studied. The main contributions are as follows:As the basic objects of scheduling, SDTR and satellite data transmission task (SDTT) are the basis of researching SDTSP. This paper presents the concepts of SDTR and SDTT firstly, and then constructs their models. These models formalize the description of SDTR and SDTT.Aim to Usable time window (UTW), this paper constructs its basic index system at first, and then analyses the coverage relationship between different UTWs, and brings forward the concept of coverage degree (CD). The use of UTW reduces the complexity of SDTSP. The index system of UTW and CD can be need to support the selection of UTW reasonably during scheduling process.This paper analyses the conflicts between single data transmission tasks, and then presents the concept of possible conflict, designs the algorithm of dividing single data transmission task set, and gives conflict evaluating indexes of UTW. Possible conflict is an important concept presented based on the characteristics of SDTT. A valid method based on dividing algorithm is proposed to reducing the scale of SDTSP and the runtime of scheduling algorithm. The conflict evaluating indexes of UTW provide support for reducing influences between tasks and scheduling as more tasks as possible.Multi-constraint concurrence is the main characteristic of SDTSP. First, the constraints of SDTSP are formalized, and then a general representation form and scheduling object function of SDTSP model are designed. Based on above, this paper builds SDTSP model. According to the characteristic of scheduling task set and for solving SDTSP, a two phases scheduling schema is proposed, which provides a framework for designing scheduling algorithms.During researching on the two phases scheduling algorithm based on synthetical priority of satellite data transmission, this paper presents synthetical priority concept and its computing formulas, and then designs satellite real-time data transmission task scheduling algorithm based on bi-synthetical priority and satellite storage data transmission task scheduling algorithm based on synthetical priority. By employing these two algorithms, this two phases scheduling algorithm achieves two phases scheduling for two kinds of tasks. The two phases scheduling algorithm provides a heuristic method for solving SDTSP.Another two phases scheduling algorithm based on immune genetic algorithm of satellite data transmission is designed for solving SDTSP. In this algorithm, immune genetic algorithm is utilized for scheduling satellite storage data transmission tasks, while the same algorithm as the former two phases scheduling algorithm is used to achieve satellite real-time data transmission tasks scheduling.In the end, a satellite data transmission scheduling software system is designed. Serveral scenarios are designed to show the performance and efficiency of these two phases scheduling algorithms.