在煤矿井下精确的人员、货物位置信息对于保障煤矿安全生产和矿工人身安全具有重要意义。本文基于超宽带（UWB，Ultra Wide Band）通信的定位技术，以煤矿井下作为实际应用场景，开展有关于室内定位关键技术的研究。本文围绕着基于时间测距的两种定位方式展开研究工作，它们分别是到达时间（TOA，time of arrival）和到达时间差（TDOA，time difference of arrival）。本文的主要研究内容如下：
Recently, Location Based Services (LBS) technologies have been integrated into our daily life as a new strategic industry. Research on indoor localization has become a hot topic with increasing demands for precise localization in the fields of emergency rescue, public security and shopping services. The indoor localization technologies that already exist are easy to be interfered by harsh indoor environments and have low precision and small system capacities. As a result, the spread of these techniques didn’t realize. Especially in coal mines, the rescue work becomes difficult due to the inaccurate location information.
Precise location information of miners and cargos in coal mines is of great significance for the safety of the miners and the safety in production. In the paper, we focus our research on the key techniques of indoor localization for mine application scenarios, which is based on Ultra Wide Band (UWB) technology. The main research contents in this paper include two classical ranging methods in time-based localization: time of arrival (TOA) technique and time difference of arrival (TDOA) technique. The details are as follows:
Firstly, a novel non-line-of-sight (NLOS) identification and mitigation method in TOA location is proposed, which solves the problem that the performance of classical least squares (LS) algorithm severely degrades in NLOS environments. The modified algorithm can attenuate NLOS errors caused by human bodies so that high localization resolution will be realized in NLOS environments.
Secondly, we introduce a clock synchronization method based on the Kalman filter in TDOA location, which can provide a nanosecond level synchronization resolution and has good robustness to NLOS errors and clock synchronization period. Experiments show that the clock synchronization is quite suitable for Real Time Locating Systems (RTLS).
Finally, we compare TOA scheme with TDOA scheme and choose TDOA method for the design of moving target precise positioning system in coal mines, which is composed of tags, anchors and an upper computer.
In this paper, key techniques such as NLOS error attenuation and clock synchronization have been studied and a moving target precise positioning system in coal mines is designed based on TDOA method. All the work in this paper lays the foundation for the implementation of precise positioning system in coal mines.