Mine wifi system and its implementation method with the function of secondary spread spectrum accurate distance measurement

Abstract

The invention provides a mine WIFI system capable of accurate range finding of secondary spread spectrum, and aims at solving the problem that WIFI technology is suitable for mine wideband wireless transmission and communication but causes inaccurate positioning due to weak range finding capability. An m sequence is used for carrying out secondary spectrum spreading on range finding WIFI signals in a movement station; and a double digital matched filter spreading code capturing algorithm is designed in a base station to capture the range finding signals, a high-speed digital matched filter captures the m sequence of secondary spread spectrum signals and obtains fine measurement time which decides the range finding precision to be 0.49m, and a low-speed digital filter is used to capture a Barker sequence of the WIFI signals and obtain coarse measurement time which decides the range finding distance to be 300m. According to the system, two MAC control frames independent from a present WIFI system are designed for range finding, and range finding does not influence normal WIFI communication of the system. Reliable technical support is provided for a developer accurate positioning system on the basis of the mine WIFI system.

Description

technical field [0001] The invention relates to a method for precise distance measurement in a WIFI communication system, specifically, in a traditional WIFI communication system, a direct sequence is used to perform secondary frequency spreading on a WIFI signal to realize precise distance measurement in a WIFI system, which belongs to radio / WIFI In the field of positioning technology, it is suitable for the integration of underground communication systems and staff positioning systems in coal mines. Background technique [0002] The underground personnel positioning system and the mine communication system belong to the "six major safety and risk avoidance systems" of coal mines, which play an important role in ensuring the safe production of coal mines. WIFI technology has been widely used in all walks of life. It has the characteristics of long transmission distance, high bandwidth, and easy networking. The deployment of base stations is convenient, and mobile terminals ...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the inherent system problem that the existing WIFI system cannot provide accurate ranging information, the present invention provides a mine WIFI communication system with the function of secondary spread spectrum accurate ranging and its implementation method, using the existing WIFI platform, adopting A new signal system combining DSSS-DSSS is adopted. Without affecting the normal operation of the original WIFI system, the WIFI signal is spread-spectrum multiplexed to increase the code rate of the WIFI signal. The PN code of the FPGA processor is used to capture the WIFI signal after the second spread. , can obtain higher-precision signal propagation time of both communication parties, realize accurate ranging between the two, and provide reliable technical support for the construction of an accurate positioning system for underground personnel in coal mines

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