Hybrid Discrete Graph Based Data Acquisition And Transmission For Space Remote Sensing

The space remote sensing system uses satellites and unmanned aerial vehicles as the carrier platform to approach remote sensing targets and ground base stations,completing data acquisition and transmission through a variety of sensing and transmission equipment.In recent years,with the increasing remote sensing satellite and UAV numbers,heterogeneous nodes in the space remote sensing system can form a space remote sensing network in a cooperative manner,expanding the system’s observation and communication space-time coverage.However,due to the diverse and continuous movement of nodes in the network,the coverage of sensing equipment and the ability of maneuvering adjustment are quite different,and the stability of the transmission link between nodes and the end-to-end transmission path is insufficient,which makes it difficult to effectively use network resources and coordinate observations.And network transmission is difficult to implement,and the problem of long system response delay still exists.Therefore,facing the remote sensing tasks with massive data and high time-sensitive requirements in the future,the research of fast data acquisition and efficient transmission technology is imminent.This dissertation aims to reduce the response time delay of space remote sensing,and focuses on the topology modeling and analysis of space remote sensing network and data acquisition and transmission strategies.By expanding the time and space dimensions to describe the dynamic time-varying topology,establish a hybrid spaceoriented remote sensing network Discrete time-varying graph model to realize the mapping between network resources and edge weights in the model.Based on the proposed time-varying graph model,design the satellite and UAV collaborative data acquisition optimization plan,respectively propose the satellite remote sensing data transmission delay optimization strategy and the delay constraint UAV remote sensing data transmission energy consumption optimization strategy to solve the space remote sensing The data acquisition and transmission delay is large and the system response is not timely.Specific research on the following aspects:Construct a hybrid discrete time-varying graph model for space remote sensing network.Aiming at the problem of complex topological structure and time-varying dynamics caused by the diverse types of network platforms and continuous movement,combined with the data acquisition and transmission process,a time-varying graph theoretical model for space remote sensing networks is proposed.Analyze and compare the motion characteristics of different nodes in the network.Through topology construction and topology mapping,design a hybrid discrete time-varying graph model that includes updating discrete graphs and predicting discrete graphs.Through dynamic time quantification,the topology can be accurately described,and the midpoint and sum of the model can be reduced.The number of edges can provide a basis for subsequent performance analysis and optimization.Propose a data collaborative acquisition scheme for space remote sensing system.In view of the fixed trajectory of the carrier platform and the limited observation coverage of the onboard equipment,the remote sensing data acquisition time delay is large.According to the characteristics of satellite and UAV imaging,the target area is divided into multiple sub-tasks,and remote sensing satellites with the number of observations are designed respectively.Side roll angle optimization coverage strategy and remote sensing UAV observation coverage time optimization trajectory planning algorithm to realize the coordinated utilization of heterogeneous platform observation resources,ensure the observation quality and reduce the time delay of the data acquisition process,and provide network topology for the optimization of the transmission process Structure and data business model.Design a satellite remote sensing data transmission strategy based on updating the discrete map.Aiming at the problem of the lack of end-to-end transmission path and the long delay of data return due to the dynamic satellite remote sensing network topology and the large space-time range,combined with the delay-tolerant/break-tolerant network protocol system,the data packet transmission process in the multi-threaded scenario is analyzed,and storage-Transmission-delay-equipment multi-constrained link and network transmission capacity analysis method.For single-task and multi-task remote sensing data transmission requirements,a constraint optimization problem with minimum task delay as the goal is established,and the delay of the data transmission process is reduced through flow allocation,so as to realize the timely return of satellite remote sensing data.Design a remote sensing data transmission strategy based on predictive discrete map UAV.Aiming at the problem of unbalanced point-to-point link due to the dynamics of remote sensing network nodes and limited energy,the data return delay and energy consumption are difficult to balance,combined with the observation planning of remote sensing UAVs,relay UAVs are designed through greedy strategies The flight track reduces the storage time of data in the remote sensing drone node.Based on the Gaussian Markov motion process,the connection characteristic model of the link between UAVs is proposed.Analyze the energy consumption of the UAV performing remote sensing missions,establish a time-delay-constrained minimum energy consumption data transmission constraint optimization problem,ensure the timeliness of the UAV remote sensing data return through flow balance,and reduce the system energy consumption.