A spread spectrum signal pseudo code fast capturing device and method

Abstract

The invention discloses a spread spectrum signal pseudo code rapid capturing device and a spread spectrum signal pseudo code rapid capturing method. The capture device includes: a N-point FFT computing unit, a data caching unit, a pseudo code spectrum storage unit, a weighting coefficient storage unit, a data reading unit, a data processing unit, a B point IFFT calculation unit and a code phase and Doppler estimation unit, the capture device adopts a frequency domain mixed downsampling combined parallel capture method, and signal capture is completed through cooperation of all the units. According to the spread spectrum signal pseudo code rapid capture device and the capture method, a frequency domain mixed downsampling combined parallel capture method is adopted, mixed downsampling is carried out on the frequency domain sequence corresponding to the cross-correlation sequence, the position of a correlation peak can be rapidly estimated at a low calculation cost, and all cross-correlation results do not need to be calculated; and only one N-point FFT calculation unit and one B-point IFFT calculation unit are needed, so that two-dimensional parallel search of a code phase and a carrier frequency can be realized with low hardware overhead, and the pseudo code capturing time is remarkably shortened.

Description

technical field [0001] The invention relates to the technical field of communication engineering, in particular to a device and method for quickly capturing pseudo-codes of spread spectrum signals. Background technique [0002] Spread spectrum communication, that is, spread spectrum communication technology (Spread Spectrum Communication), is a communication technology that disperses the spectrum of the transmission signal to a wider bandwidth than its original bandwidth. Because spread spectrum communication has strong concealment and anti-interference ability Strong and other advantages, it is widely used in satellite-to-earth low-speed communication and other fields. [0003] At present, in satellite-ground low-speed communication, due to the limited visible time of low-orbit satellites and the high relative speed between low-orbit satellites and ground equipment, the Doppler effect will appear when low-orbit satellites communicate with ground equipment wirelessly, that i...

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Problems solved by technology

However, when the values ​​of N and Q are large, the processing delay of the joint parallel search method in the frequency domain will be significantly increased; and the acquisition device is required to work at a higher clock frequency, which will affect the on-orbit stability of the acquisition device

When it is necessary to reduce the processing delay to achieve low-latency reliable capture, the existing method is to reduce the processing delay by increasing the parameter p, that is, increasing the number of Doppler frequencies to be searched in parallel. However, due to the IFFT calculation set by the capture device The number of units and the storage overhead are proportional to the parameter p. If the parameter p is increased, the computing resources and storage overhead will be doubled.

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