Method for acquiring GPS weak signals

Abstract

The invention discloses a method for acquiring GPS weak signals, which comprises the following steps: carrying out correlation operation for GPS satellite signals received in the set time; ordering the obtained correlation operation results, recording frequency points corresponding to the forward correlation operation results, and recording as once-through operation; repeating the step 1 and the step 2 until the set operation number is reached; listing the frequency points corresponding to the forward correlation operation results of each group of data, counting up the positions of the frequency points and the number of appearance in each position, and obtaining the statistical vectors of the recorded frequency points; if at least one of the statistical vectors is larger than or equal to the threshold value, acquiring successfully; if all the statistical vectors are smaller than the threshold value, acquiring unsuccessfully. For weak signals, because no obvious correlation peaks exist, a general acquiring method can not realize effective acquisition; but for the acquisition algorithm of the invention, even though no largest and second largest correlation peaks and the like exist, the acquisition can success and the amount of calculation is not great.

Description

technical field [0001] The invention relates to a GPS signal acquisition method. Background technique [0002] The Global Positioning System (GPS) can provide users with accurate position, speed, time and other information, and has been widely used. However, in complex environments such as indoors, forests, and cities, the GPS signal is severely attenuated, which makes positioning The accuracy of the GPS is seriously affected. When the signal is weakened to a certain extent, it will make the GPS unable to locate, which greatly limits the application field of GPS. Acquisition is the core step in GPS reception, so the quality of the acquisition method will greatly affect the positioning accuracy and application field of GPS, so the acquisition method for weak signals is particularly important. [0003] As we all know, the three-dimensional positioning of a general GPS receiver requires 4 satellites or more than 4 satellite signals. Since the distribution of satellites will pl...

AI Technical Summary

Problems solved by technology

[0006]Outdoors, because the GPS signal is strong enough, the signal can be captured within 1 ms of the correlation time, but in complex environments such as indoors, forests, and cities, the GPS signal Attenuation, in terms of capture, is: it cannot be captured, so it cannot be tracked, which in turn affects the accuracy of positioning

The capture of weak GPS signals is generally achieved by extending the correlation time, but as the correlation time increases, the amount of calculation increases accordingly

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