Based On The Research And Implementation Of The Hardware-in-the-loop Simulation Of Spread Spectrum Receiver

In the increasingly complex electromagnetic environment, Spread Spectrum Communication System has become the mainstream communication ways of21century because of its anti-jamming ability, anti-interception ability, anti-multipath ability and good sub-addressing capability. Direct Sequence Spread Spectrum (DSSS) System is the typical application of Spread Spectrum Communication System, which is widely used in positioning and civil communication area. The advantages of DSSS are depending on the spread spectrum code. Therefore, choosing the code sequence with good autocorrelation property and high complexity can effectively improve the performance of the system.Synchronization Technique decides the work quality of DSSS system. This article focuses on the study of DSSS System in the spreading code synchronization and carrier synchronization. This paper mainly studies the detection performance and time performance of single integral serial search algorithm, double integral serial search algorithm and single integral parallel search algorithm. Meanwhile, this article studies the improvement of capture performance when using the adaptive threshold based on constant false-alarm rate (CFAR) and the adaptive non coherent accumulation. Then, associating the search algorithm based on the adaptive non coherent accumulation with the adaptive threshold based on constant false-alarm rate as the spread spectrum code acquisition scheme of the DSSS receiver. At the same time, derive the detection performance and time performance of this scheme. And, studying the performance of the non coherent delay locked loop used in the tracking of spread spectrum code. In addition, this article is studying the Costas loop which is used widely in close loop carrier synchronization and the maximum likelihood estimate algorithm which is used widely in open loop carrier synchronization, and comparing the advantages and disadvantages of the two algorithms.At the same time, based on the research and comparison of the spread spectrum code acquisition algorithm, spread spectrum tracking algorithm and carrier synchroniza-tion algorithm, this article design a BPSK/QPSK-DSSS software receiver. Then, this paper constructs a spread spectrum simulation platform to analysis and measure the performance of the soft receiver. Meanwhile, building a real signal source with general instrument and using the real signal source to measure the performance the soft receiver.The work of this article provides the basis for the reliable technical reference of overall DSSS system and the design of practical system...