Research On Multiple Access And Code Division Access Algorithms For Satellite Formation

In recent years,China's aerospace industry has flourished.In order to realize space exploration in the dark period of the universe,a space-distributed interference array formed by a main satellite and eight sub-satellites in a 300 km orbit around the moon-shaped orbital "satellite formation" was introduced,baseline changes resulting from formation co-observation and orbital evolution.The formation of satellites needs to establish a reliable and cohesive inter-satellite network space between small satellites.The inter-satellite communication link is used to achieve multiple access to satellite formations.The framework is an open system interconnection model(OSI),especially Road Access Control Sublayer(MAC),in which "a protocol centered on code division multiple access",because of its good anti-interference,concealment,low interception and reusability.This article will detail the reception related issues of the spread spectrum signal.The research content of the article is as follows:(1)Outlined the ways of satellite formation multi-access,and analyzed the advantages,disadvantages and similarities and differences of these methods.(2)Synchronization is realized by spread spectrum communication system based on code division multiple access in multi-access mode.The principle of spread spectrum communication and the composition of spread spectrum signal are summarized,and the Doppler frequency offset caused by high-speed motion of satellite is analyzed.Good autocorrelation with pseudo-random sequences provides an application background for the introduction of capture algorithms.(3)Analyzed the characteristics and similarities and differences between "time domain serial acquisition algorithm" and "parallel code phase acquisition algorithm",and improved the sensitivity by coherent integration method and non-coherent integration method,and improved the probability of successful capture,and discussed the signal.Detection algorithm.(4)A quantization method based on “best distortion” and a new evaluation index “carrier-to-noise ratio” are proposed,which can be used to measure the quantization loss before capture.(5)The simulation of the parallel algorithm based on the best distortion quantization method is carried out to verify the feasibility of the best distortion quantization method.