【作者】 陈奎；

【导师】 徐钊；

【作者基本信息】 中国矿业大学 ， 通信与信息系统， 2009， 博士

【摘要】 采用无线技术对人员与设备进行定位与跟踪是增加煤矿监控手段、保障煤矿安全生产的主要途径之一。本文在分析了无线定位基本算法和井下信道特点的基础上,研究井下无线定位与跟踪的相关算法,着重研究以宽带信号为基础的定位与跟踪算法。OFDM信号具有很强的多径抑制能力,文中使用OFDM信号作为宽带定位信号,在频域讨论OFDM信号的TOA估计。提出利用MUSIC超分辨率算法实现精确的TOA估计。为此,讨论变换域信道估计算法,将其推广到二维空间并给出二维插值的改进方法。在OFDM多天线接收的基础上,提出超分辨率AOA算法,并利用波束形成方法对AOA算法改进。针对盲巷道或巷道分支,提出联合TOA/AOA超分辨率算法,使用一个参考节点完成目标定位。最后,将矩阵束技术引入TOA和AOA的超分辨率估计中,以减少MUSIC算法的计算量。考虑到基于UWB的井下WSN节点是硬件受限的。为了减少计算量,提出一种两步定位方法,将低速非相关能量采集和高速相关匹配滤波的定位算法结合起来。针对定位过程中两个阶段的归一化门限设置,提出基于最大最小能量比MMR的归一化门限建模方法。在UWB频域TOA算法中,提出一种减少计算量的归一化乘幂法,采用迭代的方法取代MUSIC类算法中的奇异值分解SVD。对于井下信道的非视距传播,利用代价函数给出NLOS鉴别方法。结合巷道的几何特征,提出利用几何面积计算形心的算法对NLOS影响进行消减,在此基础上利用几何定位精度因子GDOP选择或加权TOA测量值,进一步减少NLOS误差。对于多径的抑制,讨论了基于TK算子的多径抑制方法,给出一种基于互TK能量算子的直接TDOA估计方法,得到独立于TOA估计的TDOA估计。本文分析和研究了宽带信号在井下定位中的方法和需要解决的问题。依据巷道的特点,甄选适合的定位算法以提高定位精度、消减NLOS和多径传播的影响。当然,井下无线定位还有很多有待解决的问题,如:无线定位的本安特性;井下巷道的信道特点和物理特点使得需要在各种定位技术的基础上融合或折中;另外,井下定位还需要在定位精度和定位成本之间需要权衡,但至今还没有针对井下无线定位的行业标准或规范。更多还原

【Abstract】 Adopting wireless positioning and tracking technology is the key to enrich and improve the supervision & monitoring methods, and is one of the main means to ensure the coal safety. In this dissertation, after analyzing many wireless positioning algorithms and underground channel characteristics, the underground wireless positioning & tracing algorithm is studied and analized, especially the positioning algorithms based on wideband and/or ultra-wide-band signals.Because of its multi-paths suppression peculiarities, the OFDM has been used as broadband signal for mine underground posositioning, and the frequency domain TOA and frequency-domain super-resolution TOA estimation is discussed and achieved accurately by MUSIC algorithm. In order to obtain accurate channel frequency response of OFDM signal, the transform domain channel estimation is extended to two-dimensional and given an improved interpolation method. Using multi-antenna array, a super-resolution AOA algorithm is proposed and improved by taking advantage of beamforming technology. For the positioning in blind or branched tunnel, a joint super-resolution TOA/AOA algorithm is proposed by using only one access point. Taking into account the computation of the MUSIC algorithm, it will be substituted by the Matrix-Pencil technique in super-resolution TOA and/or AOA estimation process.The nodes of UWB-based WSN in mine working faces are hardware-restrained. A compromise two-step method is proposed in time-domain for WSN node, which includes a low-speed non-correlation process and a high-speed correlation-matched filter process. The normalized-threshold in energy-acquisition and correlation-match stages are presented and discussed based on the maximum to minimum energy ratio (MMR) modele. To reduce the computation of the frequency domain TOA positioning algorithm for the UWB signals, the normalized-power-law is substituted for the MUSIC type algorithm by using iterative method to replace the singular value decomposition SVD in MUSIC.After analyzing the impacts of underground NLOS, a cost-function method is givev to identify NLOS transmission. Considering geometric characteristics of the tunnel, the simple geometric area-centroid algorithm is proposed to reduce the NLOS impacts. And then, using the GDOP to select or weight TOA measurements to reduce the impacts of NLOS transmission further. For multipath condition, the multipath-restrain performance of the TK operator is studied firstly. Then, the cross-TK energy operator and the signal similarity based on it are analysed. So, a direct TDOA estimation algorithm based on cross-TK energy operator is proposed to gain the estimated TDOA which is independent of the TOA estinmations.Of course, the underground wireless location have a lot of questions to be resolved yet, such as intrinsic safe characteristic of wireless positioning; the features of underground channel and physical make it necessary to integrate or compromise among various positioning technology; In addition, the underground need trade-offs between positioning accuracy and cost, has no industry standards or norms for underground wireless positioning unfortunately.更多还原