Research On The Location Approaches Of Miners Based On EMW Ranging

In this thesis, the EMW-based precise ranging technology was studied, a location system based on PTR8000 was proposed fulfilling coarse location. In this system, RF signals are the carrier of the location information, which will be transmitted by wires to the managing PC on the ground, and the coarse location was realized by the algorithm in the monitoring PC.A thorough research of the characteristics of radio propagation in mine tunnels and the precise ranging technology was carried out in this thesis. To the three precise location methods RSS, TOA, AOA, their feasibility in mine application was analyzed in detail, and. their advantages and disadvantages were pointed out. Based on the comparison, the TOA method was concluded to be the best one for location in mine tunnels.TOA method can be realized in both the time and frequency domain. The method in time domain needs extremely precise timing circuit, but to the situation of the hardware circuit at present, the timing precision can't meet the requirements of ranging, so the TOA method in frequency domain was proposed. In frequency domain, the channel can be modeled as a signal in time domain cumulated by some sine components, so the TDE(Time Delay Estimation) is equal to SE(Spectral Estimation). The SVD-based subspace method is one of the best spectral Estimation algorithms with a infinite resolvability in theory, according to which the super-resolution TOA algorithm(MUSIC) was proposed in this thesis. In high SNR conditions, MUSIC algorithm has perfect performance.To the difficulties in the rank-deciding in low SNR situations, a cross-spectral MUSIC algorithm was proposed, reducing efficiently the influence of the noise. Based on all above, plenty of simulation work was carried out, and the performances of the three methods were compared. The simulation results show that the TOA (MUSIC) algorithm is super-resolution, stable and robust. With a 40MHz bandwidth, the average error in simulation is only 10.5cm meeting the requirements of location application in mine tunnels well. With the booming technology OFDM, this algorithm can be perfectly realized.