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GPS weak signal capturing method based on sequential probability ratio

A sequential probability ratio and weak signal technology, applied in the direction of measuring devices, radio wave measurement systems, satellite radio beacon positioning systems, etc., can solve the problems of shortening the acquisition time of strong signals and high time complexity, and increase the average acquisition time Effect

Inactive Publication Date: 2011-03-09
BEIHANG UNIV
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Problems solved by technology

[0008] The purpose of the present invention is to: overcome the shortcoming of the existing GPS weak signal capture algorithm with too high time complexity, provide a GPS weak signal capture algorithm based on sequential probability ratio detection, adapt to the capture of signals of different strengths, and effectively shorten the duration of strong signals. capture time, thereby reducing the overall capture time and improving capture performance

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  • GPS weak signal capturing method based on sequential probability ratio
  • GPS weak signal capturing method based on sequential probability ratio
  • GPS weak signal capturing method based on sequential probability ratio

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Embodiment Construction

[0037] Such as figure 1 Shown, the GPS weak signal acquisition method based on sequential probability ratio detection of the present invention, its realization steps are as follows:

[0038] (1) N ms output by the front end of the receiver (when a high-sensitivity receiver captures a weak signal, it needs to process a section of data long enough to capture the signal; the length of this section of data is represented by time, and the length of time is in The typical value in this patent algorithm is 4ms, and it can also be adjusted to other values, which are represented by N ms here) The intermediate frequency digital signal after sampling and quantization processing is used for two-dimensional search in parallel code domain, and the package of two-dimensional search in parallel code domain is obtained network diagram;

[0039] The present invention is a high-efficiency acquisition method suitable for high-sensitivity receivers. The position in the receiver structure is as fo...

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Abstract

The invention relates to a GPS weak signal capturing method based on a sequential probability ratio. The method comprises the steps of: (1) performing parallel code domain planar search on a sampled and quantized intermediate frequency digital signal which is output by the front end of a receiver, (2) calculating a threshold value corresponding to different unrelated accumulation times under a preset condition of false-alarm probability, (3) calculating a probability density function contained in an assumed signal, (4) calculating a probability (5) that the assumed signal is more than the threshold value, ending the search stage, if a signal is captured, or repeating the step (3), (4), (5) if no signal is captured, and if the unrelated integral accumulation times M reaches to 100 but still no signal is fund, that means no signal exists, ending the capturing stage as well. The method of the invention can efficiently shorten the capturing time of strong signals, reduce the whole capturing time and increase the capturing property.

Description

technical field [0001] The invention relates to the field of GPS (Global Position System, Global Positioning System) signal data processing, in particular to a method for capturing weak GPS signals based on SPRT (Sequential Probability Ratio Test, Sequential Probability Ratio Test). Background technique [0002] For ordinary GPS receivers, it can only receive signals with a power greater than -160dBW. When the carrier carrying the GPS receiver is running indoors, in urban canyons, forests and high earth orbits, the GPS signal is blocked and attenuated, the satellite signal received by the receiver is extremely weak, and the receiver "cannot see" the GPS satellite, it is Navigation and positioning cannot be performed. GPS receiver acquisition is a process of estimating PRN (Pseudo Random Noise) code delay and carrier Doppler. This information is used to initialize the tracking loop and is the basis for the receiver to perform positioning. [0003] In terms of receiving sate...

Claims

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Application Information

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IPC IPC(8): G01S19/24G01S19/30
Inventor 秦红磊牛靖逸
Owner BEIHANG UNIV
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