System and method for capturing spread-spectrum signals

Abstract

The present invention provides a system and a method for capturing spread-spectrum signals and is applied to the field of direct sequence spread-spectrum communication. The system comprises a satellite navigation time-service module, a trigger logical module, a clock error measurement module and a Doppler calculation module. The satellite navigation time-service module outputs the location, the speed and the time information of a carrier, wherein the time information contains the coordinated universal time and the pulse per second. The trigger logical module receives the coordinated universal time and the pulse per second output by the satellite navigation time-service module, and generates a trigger signal to trigger and generate a spread-spectrum code with the coordinated universal time as a time reference and the pulse per second as an input signal. The clock error measurement module receives the pulse per second output by the satellite navigation time-service module, and then calculates the clock error. The Doppler calculation module receives the location, the speed and the time information output by the satellite navigation time-service module, and calculates the Doppler deviation caused by the relative movement of the carrier. Based on the time-service function of a satellite navigation system, spread-spectrum signals can be quickly captured, while no large amount of hardware resources is occupied. Meanwhile, the communication efficiency is high. The method and the system are particularly advantageous to bursty communications that are shorter in communication time.

Description

technical field [0001] The present invention generally relates to spread spectrum communication technology, in particular, relates to a spread spectrum signal acquisition system and method based on satellite navigation timing function for direct sequence spread spectrum communication. Background technique [0002] Spread spectrum communication technology is a method of information transmission, which modulates the data information to be transmitted with a spread spectrum code sequence, and then transmits after realizing spectrum expansion; the receiving end uses the same spread spectrum code sequence for related synchronous reception and despreading And restore the original data information. Spread spectrum communication has the advantages of good anti-interference performance, good confidentiality performance, low spectral density, small interference to other communication systems, accurate timing and ranging, etc. It was mainly used in military communication systems in the...

AI Technical Summary

Problems solved by technology

In addition, there is an acquisition method based on the carrier frequency Fast Fourier Transform (FFT) algorithm. Although it can overcome the influence of the Doppler frequency shift on the pseudo-code acquisition and achieve the purpose of rapid acquisition, the power change of the received signal is required to be Small, when the power of the received signal changes greatly, adaptive threshold adjustment must be performed to achieve correct capture, which increases the complexity and capture time of the system, and cannot complete the pseudo-code capture of short-term burst communication

[0008] In summary, since the code phase and frequency offset are random quantities and lack corresponding prior information, in the existing acquisition methods, the acquisition algorithm has a large amount of computation and needs to occupy a large amount of hardware resources; and the detection of the signal is A probabilistic event requires multiple threshold judgments and adjustments. Therefore, the capture process often takes a long time, which reduces communication efficiency and is extremely unfavorable for burst communications with short communication times.

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