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It is important that precise positioning and navigation of underground personnel for intelligent hedging and mine rescue in mine accidents or disasters. At present, there are many passive positioning methods such as RFID, Zigbee and other positioning products in the underground, which cannot work normally while there is power supply interruption or signal interruption in the underground. GRPM is a new active underground positioning method combining radio frequency identification and geomagnetic matching technology, which the positioning accuracy reach to the sub-meter level when the miner with the GRPM device in the underground. Geomagnetic matching algorithm is the core technology of GRPM, and its performance directly affects the accuracy of the geomagnetic positioning. For the MSD, MAD and PORD matching algorithms have low precision in geomagnetic matching localization; it is proposed a novel matching algorithm named MPMD to achieve underground geomagnetic precise positioning in this paper which is an optimal estimation of the eigenvector product of underground two magnetic variables. The matching test of underground geomagnetic positioning for the performance of MPMD algorithm was carried out in 9 tunnels about 150 meters long and 6 meters wide in mine. The geomagnetic data of the total magnetic field and the three axis component are measured with the portable FVM400 fluxgate magnetometer. MSD, MAD and MPMD algorithms were used to matching test for analyzed their effective matching length, positioning error, noise immunity. The test result shows that the MPMD algorithm has the advantages of minimum matching position error and better noise immunity than MSD, MAD matching algorithms under the same experimental conditions. It is suitable for the complications of underground geomagnetic spatial distribution, and meets the requirements of underground emergency refuge and navigation. However, matching process of MPMD algorithm is time-consuming, it can be further improved the search space and search strategy in later research.

Due to the short wavelength, Millimeter-wave interferometric synthetic aperture radar (MMW-In SAR) imaging requires higher precision of the platform trajectory compared with other centimeter-wave bands. In the case of non-ideal trajectory, traditional SAR imaging methods may suffer from several problems, e.g. Image defocusing and motion error correction. In addition, these methods mainly produce In SAR image via range-azimuth plane projection. If the terrain height is abruptly changed, these methods could cause serious geometric distortion in In SAR image. To overcome the disadvantages of these conventional methods in MMW-In SAR imaging, a modified back projection via ground projection (GP-BP) is proposed in this paper. In this theme, the echoes of the different antennas of MMW-In SAR are projected into the same ground space for both image focusing and interferogram extraction. Simulation and experiment results verify the effectiveness of GP-BP, and demonstrate that it can improve the quality of both image focusing and interferometric phase extraction in the condition of complex motion, and also can reduce the geometric distortion and the phase wrapping in the case of the abrupt terrain.

In this paper, death accident in coal mines were tidied using the method of mathematical statistic from January 2005 to June 2009. By linking aspect such as accident types, time rule of accident happens, provincial statistics, causes of accident, the thesis analyzed the characteristics and rules of coal mine accidents, introduced the particularity and damages of coal mine accidents, the results has vital significance to enhance the technique of forecasting and preventing the coal mine accidents, establish perfect the countermeasure and emergency disposal plans for accident, and do well the safety in producing.