Weak signal capturing method based on 1/5 bit differential circulation coherent integration

Abstract

The invention aims at providing a weak signal capturing method based on 1 / 5 bit differential circulation coherent integration. The method comprises the following steps of obtaining a section of intermediate-frequency signal data; performing carrier stripping treatment on the received signal data, performing data segmentation on the data without carrier; performing self-superposition and FFT (fast Fourier transform) on every data block; performing FFT and conjugation on locally-generated C / A codes, and multiplying the conjugate value with every result obtained in the step above and performing IFFT (inverse fast Fourier transform); performing complex conjugate multiplying on every data block processed in the step above and the data of the neighboring data blocks with data overlaying, and then performing grouped correlation summation; judging the volumes of obtained five results, obtaining the peak values of the results without data jump, comparing the peak values with a set threshold value gamma to determine whether signals are captured successfully. The weak signal capturing method based on the 1 / 5 bit differential circulation coherent integration can effectively help capture weak signals and improve the adaptability of a receiver to the weak signals.

Description

technical field [0001] The invention relates to a signal processing method, in particular to a signal capturing method. Background technique [0002] In the 1970s, the U.S. Department of Defense and the Army, Navy and Air Force began to develop the Global Satellite Positioning System, or GPS for short. GPS can provide users with accurate location, speed, time and other information on a global scale, and has been widely used. The GPS system is the earliest and most mature navigation and positioning system. Due to the superiority of GPS, it has attracted widespread attention. It has a wide range of applications, including providing navigation services for users anywhere on the earth's surface, near the earth's surface, and in outer space, but there are still limitations: such as In complex environments such as indoors, forests, and cities, where the signal will be attenuated to a very weak level, GPS cannot work well. If the GPS receiver can perform positioning work under w...

AI Technical Summary

Problems solved by technology

Due to the superiority of GPS, it has attracted widespread attention. It has a wide range of applications, including providing navigation services for users anywhere on the earth's surface, near the earth's surface, and in outer space, but there are still limitations: such as In complex environments such as indoors, forests, and cities, where the signal will be attenuated to a very weak level, GPS will not work well

These two methods have certain defects: for coherent integration, due to the limitation of data bit jumps, the length of coherent integration generally cannot exceed one data bit, that is, 20ms, otherwise it may be caused by data bits. The jump of the coherent integration makes the coherent integral value smaller or even cancels out, so the time of the coherent integration cannot be increased without limit; although the non-coherent integration method can use the square operation to overcome the influence of the data bit jump, it is also It inevitably causes square loss, which weakens the gain of signal-to-noise ratio, so it cannot perform unlimited non-coherent integration

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