Research On Key Networking Technologies For Low Earth Orbit Remote Sensing Satellites

Low Earth Orbit(LEO)remote sensing satellites play a great role in many fields such as agricultural observation,urban management,disaster prevention and mitigation,and military affairs.In recent years,along with the development of networking technology,onboard processors,onboard routers and other Satellite loads,LEO remote sensing satellite network has been highly concerned by various countries and commercial companies.As a basic component of Space Information Network(SIN),LEO remote sensing satellite network is able to provide networked remote sensing data services through the inorbit acquisition,processing and forwarding of the remote sensing data.LEO remote sensing satellite network shows a huge commercial prospect and a high national strategic position.However,the unique characteristics of LEO remote sensing satellite network,such as high node dynamics,intermittent link and frequent switching between terminals and satellites,make the satellite networking face various challenges.This dissertation focus on the networking technologies of LEO remote sensing satellites,aiming at the challenges of the LEO remote sensing satellite network,and proposed a resilience enhanced LEO remote sensing satellite network architecture integrated with the dynamic routing,resilient transmission,intrinsic mobility and proactive security.Four key networking technologies are proposed for meeting the various networking challenges in terms of routing,transmission,mobility management and network security.The effective cooperation of the proposed key technologies ensures the efficiency,resilience,reliability and security of the LEO remote sensing satellite network.The main contributions of this dissertation is as follows:(1)Proposed a resilience enhanced LEO remote sensing satellite network architecture.Aiming at the challenges of high node dynamics,intermittent transmission,and frequent switching between terminals and satellites,integrate the features of the dynamic routing,the resilient transmission,the intrinsic mobility and the proactive security into the LEO remote sensing satellite network for enhancing the resilience from the aspects of routing,transmission,mobility support and network security.The efficient routing and transmission,seamless terminal access switching,and highly reliable network data security and transmission security of satellite network are ensured by the proposed network architecture.(2)Researching on the dynamic routing,the resilient transmission,and the intrinsic mobility mechanisms of low-orbit remote sensing satellite networks.Relying the Global Unique Identification of Equipment(E-GUID)addressing,three key technologies are proposed to copy with the challenges of dynamic nodes,intermittent transmission,and frequent switching between terminals and satellites.specifically,path-quality aided and lifetime-aware dynamic routing is proposed for enhancing the routing against dynamic topology changes.Hop-by-hop data transmission is relied upon for providing transmission resilience against ISL intermittence.Furthermore,data caching is invoked for providing resilience against intermittent communications imposed by dynamic satellite access switching.Relying on the Raspberry Pi,MATLAB and Satellite Tool Kit(STK),we employ a sem-physical simulation platform for evaluating the achievable performance of the proposed resilient network architecture.The simulation results show that the protocol overhead and the power overhead are low and the proposed protocols and algorithms are able to sensing the topology changes to ensure the efficiency and reliability of the data transmisson once the emergycy event occurs.(3)Researching on the Temporary Path Blockchain(TPB)based proactive security framework.Considering the challenges of the exsisting security mechanisms for satellite networs,such as the isolated security,end-node-only employment,large-grained detection,a TPB-based proactive security framework for protecting the whole transmission path of the LEO remote sensing network.TPB is maintained between the source and the destination to record and audit the path node behavior during transmission.The inherent traceability and unalterable natures of the blockchain ensures the reliability of the records.The Proof of Reliability(PoR)algorithm guarantees the security policy’s consistency among all nodes on the path.The cooperative protecting for the transmission path is performed as the security audit built in the TPB.This dissertation also gives the specific use cases of TPB against man-in-the-middle attack and Coremelt attack in the LEO remote sensing satellite networks,and conducts simulation experiments on the Coremelt attack detection algorithm.The experimental results show that the proposed proactive security framework is capable of detecting the Coremelt attack in LEO remote sensing satellite network timely.(4)Developing the real on-board router.Relying on the key deployment project of the Chinese Academy of Sciences,in response to the requirements of the on-board router for the low-orbit remote sensing satellite on-orbit ad-hoc network,develops low-orbit remote sensing satellite on-board router with the functions of on-orbit self-networking,high-speed data transmission,mobility support,remote control,fault recovery,software on-orbit upgrating.This dissertation presents the function and performance verification plans and the specific steps of the on-board router.The test results prove that the developed on-board router meets all requirements of the low-orbit remote sensing satellite in-orbit self-networking.