Accurate Acquisition System of Spread Spectrum Signal

Abstract

The invention discloses a spread spectrum signal accurate acquisition system, which has good real-time processing performance, small frequency measurement error, high estimation accuracy and low adaptive signal-to-noise ratio. The present invention is realized through the following technical solutions: the sampling cache module performs down-sampling processing on the received signal, and controls the ping-pong reading and writing of the sampling data; The frequency compensation of the Doppler frequency shift and the phase correction of the Doppler frequency shift of the pseudo-code; the parallel search of the phase of the pseudo-code is realized by using double-block expansion technology and fast Fourier transform; Double measurement of full coherent integration and carrier Doppler frequency shift and its rate of change; use the method of comparison and search for all integral processing data to obtain the relevant information of the integral peak, and calculate the accurate starting phase of the pseudo code and the multiplicity of the pseudo code of the spread spectrum signal. Doppler shift, Carrier Doppler shift, and Carrier Doppler rate of change.

Description

technical field [0001] The invention belongs to the field of wireless communication, and relates to a system for accurately capturing spread spectrum signals based on double-block expansion. [0002] technical background [0003] Spread spectrum communication has become the consensus of people because of its strong anti-interference and anti-multipath ability, high spectrum utilization rate, multiple access communication and many other advantages. As a modern communication system based on information theory, spread spectrum technology has many unique advantages because it uses pseudo-random codes to spread spectrum modulation for data information: it is used in communication, has strong anti-interference ability, and low transmission power , high anti-interception ability, good confidentiality performance, and has the characteristics of code division multiple access and arbitrary location; in ranging, using pseudo-random code ranging can greatly improve ranging accuracy. Bec...

AI Technical Summary

Problems solved by technology

The sliding correlation method is simple, easy to implement, and widely used, but it takes a long time and the acquisition speed is slow; the parallel frequency method uses a long-point Fast Fourier Transform (FFT) to complete the search for the carrier frequency at one time, but the acquisition The time is proportional to the length of the pseudo code, and the signal sensitivity is easy to deteriorate, and the hardware resource consumption is large; the parallel code phase method uses FFT to complete the long pseudo code phase search at one time, and the acquisition speed is fast, but the carrier frequency search range is small, and the carrier frequency The measurement error is large; based on the partial matched filter and FFT acquisition method, as a time-frequency two-dimensional parallel search method, it can not only overcome the shortcomings of slow search speed, but also overcome the serious problem of correlation peak attenuation, but it does not measure the number of carriers. Puller rate of change, difficult to adapt to high dynamic scenes

Therefore, the methods and strategies of the traditional spread spectrum signal acquisition system have their own advantages and disadvantages, and can adapt to certain specific application scenarios, but they cannot meet the mutual influence and restriction of the signal-to-noise ratio threshold, high dynamic conditions, acquisition time, hardware resources, etc. Achieving the best performance in contradiction

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