A joint positioning method of PDOA and TOF in coal mines based on UWB

The precise positioning of personnel and vehicles in coal mines is an important guarantee for safe and efficient production in coal mines. Currently, ultra-wideband (UWB) wireless communication technology is mainly used for the precise positioning of personnel and vehicles in coal mines. The positioning method that only uses the time of flight (TOF) requires two positioning substations or antennas for joint ranging and direction. It has problems such as large antenna spacing, inconvenience in installation and maintenance, and large positioning errors. In order to solve the above problems, a joint positioning method based on UWB phase difference of arrival (PDOA) and TOF is proposed for one-dimensional positioning scenarios in coal mines. This method measures the distance between the positioning card and the positioning substation through TOF, and judges the direction of the positioning card through PDOA. The method locates the positioning card based on the measured distance and direction between the positioning card and the positioning substation. This method determines the angle of arrival (AOA) of the positioning card based on the phase difference between the radio signals transmitted from the positioning card and the two antennas of the positioning substation. It does not require a large antenna spacing to determine the direction of the positioning card. It shortens the distance between the two antennas of the positioning substation. It integrates the two antennas to facilitate installation and maintenance, improving positioning precision. The underground testing results of coal mines show that the positioning precision of this method is within 15 cm. Within the test distance range of 200 m, the positioning precision is not affected by the distance. The TOF ranging value is stable within a range of ± 10 cm relative to its mean value, with good stability.