Signal decoding method and device

Abstract

The invention discloses a signal decoding method and device, and belongs to the field of well logging technology. The method comprises the following steps: carrying out autocorrelation operation on a received signal to remove a noise signal, in order to obtain a first signal; carrying out zero tracking on the first signal to remove zero drift, in order to obtain a second signal; adjusting the signal amplitude of the second signal to obtain a third signal; adjusting the phase and frequency of a local signal frame code to make the local signal frame code be synchronous with a third signal frame, and using the frame starting point as the frame starting point of the third signal; adjusting a local signal code element to make the local signal code element be synchronous with a third signal phase, and using a phase starting point as the phase starting point of the third signal; and obtaining signals within a cycle starting from the starting point of the third signal, carrying out autocorrelation operation on the signals within the cycle on an existing signal wave set, and determining the waveform of the third signal from the existing signal wave set to decode the third signal. Even if the receiver receives signals with weak intensity, and even signals with low signal to noise ratios, the signals can be accurately decoded.

Description

technical field [0001] The invention relates to the technical field of well logging, in particular to a signal decoding method and device. Background technique [0002] The measurement-while-drilling tool is a measurement tool that uses drilling fluid or electromagnetic channels as the transmission medium to continuously transmit measurement signals during the drilling process. The tool can measure geological parameters and engineering parameters near the drill bit in real time. [0003] With the promotion and use of technologies such as gas drilling and underbalanced drilling, the EMMWD (Electromagnetic Measurement While Drilling) tool, which uses the magnetotelluric channel composed of the drill string and the formation as the transmission medium, has gradually attracted people's attention. High, can transmit data without circulating drilling fluid, short measurement time, low cost and so on. [0004] Since the magnetotelluric channel composed of the formation and the dri...

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Problems solved by technology

[0004] Since the magnetotelluric channel composed of the formation and the drill string is a special channel, it attenuates the high-frequency signal in the transmission signal very severely, so that the signal frequency received by the ground is very low, and the useful signal contained in it is also very weak. Therefore, the signal transmission depth of EMMWD is short, which limits the depth of EMMWD's underground use

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