Study And Implementation Of Spreading Sequences3d Fast Acquisition Based On FPGA

The spread spectrum communication technology has made tremendous progress in thelast century, the satellite communications technology established on the basis of which iscoming into our sight. How to use of satellite communications for distance measurement,positioning, navigation efficient have become the hot topics relating to national strategicinterests. At the beginning of the spread spectrum signal is generated if the data bits wideand the length of the pseudo-random code period is not an integer the period multiplerelationship will give the recipient data demodulation to bring the points beginning andending range of uncertainty, which made the capture of the pseudo-random code shouldalso capture the data bit synchronization information. This project a pseudo-random codeacquisition algorithm, the algorithm further completed on the basis of the code phase andDoppler frequency capture data bit synchronization capture one of the most criticaltechnology in the satellite communications spreading sequence.This paper describes the pseudo-random code generation, since the relevant featuresand inter-related features based on the types and characteristics of the spread spectrumcommunication system. Then it analyzes the principles and characteristics of the serialacquisition algorithm. For a typical algorithm is one of the sliding correlation algorithms.This article describes several common parallel acquisition algorithms: the matched filteralgorithm, the direct acquisition algorithm based on fast Fourier transform, the cumulativeacquisition algorithm based on fast Fourier transform, the principle of the three algorithms,the performance to do in depth analysis and comparison.FFT-based direct average acquisition algorithm has been successfully completed andcommunication for a monitoring and control an answering machine, and after the test ofpractice of engineering, the indicators are to meet the design requirements, to furtherverify the reliability and stability of the algorithm.