空间和频率分集联合的矿井无标签目标定位方法

Mine tagless target location method based on combined space and frequency diversity

传统的有源定位技术因井下环境复杂导致工作人员不便携带标签、作业途中丢失标签,在井下目标定位应用中受限,而现有的几何法、指纹法等无源定位技术因井下存在密集的多径干扰,导致定位精度低,不适合直接应用于井下。针对上述问题,提出了一种空间和频率分集联合的矿井无标签目标定位方法。该方法基于傅里叶域非均匀采样原理,通过对波数域中的目标回波信号进行傅里叶逆变换,恢复目标散射函数,实现目标定位;采用无源宽带谐波标签生成所需谐波信号,消除发射天线引入的基频干扰;利用谐波标签的空间多样性和谐波信号的频率多样性,融合多通道信息,实现空间和频率分集联合,解决采样信息不足导致的低定位精度问题;使用差分接收算法,消除下行链路多径干扰引起的相位误差,提高矿井无标签目标定位精度。仿真实验结果表明:该方法能够有效扩展波数域覆盖范围,抑制多径干扰,实现目标准确定位;在低信噪比条件下,定位精度可达分米级。

Due to complicated underground environment,traditional active location technologies make it inconvenient for workers to carry tags or lose tags during operation,which are limited in application of underground target location,while existing passive location technologies such as geometric method,fingerprinting method and so on has low location precision due to dense multipath interference in underground,which cannot be used in underground directly.For the above problems,a mine tagless target location method based on combined space and frequency diversity is proposed.The method,which is based on non-uniform sampling principle in Fourier domain,reconstructs target reflectivity function through inverse Fourier transform of echo signals of the target in wavenumber domain,so as to realize target location.Passive broadband harmonic tags are used to generate the required harmonic signals for eliminating fundamental frequency interference introduced by transmitting antenna.The combination of space and frequency diversity is achieved by using space diversity of the tags and frequency diversity of the harmonic signals and fusing multi-channel information,which solves the problem of low location precision caused by insufficient sampling information.A differential reception algorithm is used to eliminate phase errors caused by downlink multipath interference,which can improve mine tagless target location precision.The simulated experiment results show that the method can effectively expand coverage of wavenumber domain and restrain multipath interference,so as to realize accurate target location.Under the condition of low signal-to-noise ratio,the location precision can reach decimeter level.