Method for capturing pseudocode under non-Gaussian channel

Abstract

The invention provides a method for capturing pseudocode under a non-Gaussian channel, which comprises the following steps: after being processed by the operations of carrier wave striping and pseudocode dispreading treatment, a received signal is converted into two observed quantities Xi and Xiof two I / Q branches; after being processed by the operation of squaring, the two observed quantities are added to the quadratic term gammaof a dispersion coefficient, and the obtained result is respectively divided by the two observed quantities of the I / Q branches to obtain reciprocal values so that the value of statistical quantity of each branch at a single time can be obtained; the values from 1 to M time (the variable of i) are sequentially processed by the steps of accumulation addition and square; and finally, the values of the two branches are added to each other to obtain and compare the statistical quantity with the threshold so as to judge whether a signal is captured or not, and the phase position of the local pseudocode is slid to carry out the operations of secondary judgment and comparison until the signal is captured under the circumstance that the statistical quantity is lower than the threshold. Proved by the result of comparison of performance simulation of the pseudocode capturing method of the invention and the traditional pseudocode capturing method, the detection performance of the pseudocode capturing method of the invention is drastically improved under the non-Gaussian noise environment, and the more obvious the pulse characteristic is, the more obvious the advantage of the detector designed by the invention can be.

Description

(1) Technical field [0001] The present invention relates to a signal processing method, in particular to a pseudocode capture method. (2) Background technology [0002] Many spread spectrum system receivers have to face the problem of how to extract weak signals from the background of additive interference. Spread spectrum technology is widely used because of its strong anti-interference ability, good confidentiality, and ability to resist multipath fading. It is used in the field of military and civilian communication and navigation. But these advantages can only be obtained when the local pseudo-code is synchronized with the receiving pseudo-code. The synchronization problem of pseudo code is the basic problem of spread spectrum technology. Synchronization is divided into coarse synchronization and fine synchronization, that is, signal capture and tracking. Acquisition means that the local pseudocode sequence is aligned with the received pseudocode within a certain rang...

AI Technical Summary

Problems solved by technology

But in practice, the assumption of independent Gaussian distribution of observation noise is often not valid

The noise existing in many practical channels, such as atmospheric noise and man-made pulse interference introduced by various other radio frequency systems, causes the probability density function of the observation noise to be non-Gaussian. Therefore, under the complex non-Gaussian noise model, the independent Gaussian noise The sum of squares detector obtained under the assumption cannot guarantee the best capture performance, so it is necessary to study the optimal capture method of the direct spread system under non-Gaussian noise

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