Distance-constraint-based electromagnetic and ultrasound wave combined positioning system and method for downholes

Abstract

The invention discloses a distance-constraint-based electromagnetic and ultrasound wave combined positioning system and method for coal-mine downholes. In the system, according to the spatial structure of a laneway and the attribute characteristics of electromagnetic and ultrasonic waves, a simplified formula for the ratio of the distances from a mobile node to two anchor nodes is obtained through an electromagnetic wave propagation logarithmic-normal model formula by using appropriate approximation algorithms. As the distance between the two anchor nodes is a known quantity, the longitudinal coordinate of the mobile node in the laneway is obtained by taking the distance as a constraint condition. According to the ranging principle of TOF (Time of Flight), the distance from the mobile node to the wall of the laneway is obtained through ranging by using the ultrasonic waves, the horizontal coordinate of the mobile node in the laneway is obtained, and then the two-dimensional position coordinates of the mobile node are obtained, so that the accurate positioning is realized. The method disclosed by the invention has the advantages of high positioning accuracy, low cost and little energy consumption. The system disclosed by the invention has the advantage of simple equipment structure.

Description

technical field [0001] The invention relates to the field of coal mine safety monitoring, in particular to a coal mine underground electromagnetic wave ultrasonic joint positioning system and method based on geometric constraints. Background technique [0002] Coal is the main energy source in my country, but due to the complex geological conditions and poor production conditions of coal fields in my country, the safety of underground operators is seriously threatened. In the event of an accident, the personnel on the ground need to know the specific location of the personnel underground in time. Therefore, it is of great practical significance to study the precise positioning method and system of underground targets in coal mines, which is of great practical significance for ensuring underground safety production and emergency rescue. [0003] Because the roadway is relatively closed, GPS and other existing satellite positioning on the ground cannot be used to assist the t...

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Problems solved by technology

[0011] The purpose of the present invention is to solve the problem that the accuracy of downhole target positioning technology is not enough, and the improvement of the accuracy is seriously limited by the downhole environment and cost, and considering that most of the current applications and researches are purely based on one physical transmission medium, and cannot comprehensively utilize various The current situation of the advantages of the transmission medium, a downhole target positioning system with a simple structure and a joint positioning method based on distance constraints based on electromagnetic waves and ultrasonics with high positioning accuracy and simple algorithm are disclosed

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