Research On Positioning And Tracking Device Of Natural Gas Detector

Pigging through inside oil and natural gas pipes is an operation to ensure safe and stable transportation of oil or natural gas and high enough production efficiency. However, when pig lost or block in pipe occurs, a huger security risk may be brought out leading to terrible economic losses without exact event spot location in time. So, it is important to make accurate judgment of the pig lost spot in time, and it becomes extremely vital significant to carry out research and application of pig positioning&tracking device.Based on summarizing commonly used domestic and oversea pig positioning&tracking methods, a pig positioning-tracking device to be applied in natural gas pipe has been designed and studied based on ELF electromagnetic pulse method. The researching key points includes two parts which are emission circuit with MCU adopted to output precise23Hz signals and receiving circuit with correlation detection technology applied to detect weak signals.Firstly, the principle of electromagnetic wave’s transmission has been introduced in the paper. ELF electromagnetic magnetic dipole model and electromagnetic positioning principle have been studied as well as frequency of emission signal has been determined and, simulation work about transmission and absorption of23Hz plane electromagnetic wave through several common mediums have been carried out. Secondly, hardware design and software programming of the transmitter and receiver have been completed,The hardware design mainly includes transmission block circuit and receiving block circuit, in which power converter for different chips, ELF signal transmitter, filter&lifier, correlation detection unit, A/D converter unit, memory expansion circuit for MCU AT89S52, LCD display circuit, real-time clock circuit, and interface circuits for communication with host and etc; The software programming mainly includes programming for MCU and simulation for partial circuits. Finally, the device has been tested,which shows that the receiver can locate the transmitter under certain conditions by receiving and transmitting23Hz ELF electromagnetic waves.