基于空域频域联合处理的WiFi室内定位技术
发布时间：2018-12-24 08:49
【摘要】：随着室内定位需求的普及,各种室内定位技术成为了研究的热点。然而,室内电磁环境复杂,无线信道随机变化。在WiFi定位技术中,应用最广泛的RSSI指纹库匹配定位仍存在定位精度不高,稳定性不足的缺点。为突破指纹库定位的局限,利用WiFi中信道状态信息具有更细粒度感知环境这一特性,结合OFDM通信技术和阵列测向技术,通过位置参数估计方法实现了一种全新的定位技术。本文利用当前广泛部署的普通商用WiFi设备具有多天线,多信道,多子载波的特点,通过研究信道响应模型、WiFi信号及OFDM技术的基本特性,将通信技术和阵列测向技术结合起来,通过超分辨空间谱估计的算法和稀疏重构方法恢复出多径信号的空间谱和时间谱,实现了在LOS环境下直达波分量的传播时延和入射角度参数估计,并最终给出了基于信道响应的WiFi室内定位系统实现方式及其原型架构。研究内容和创新点主要包括以下三个方面:本文首先研究了阵列测向、信道响应模型和MUSIC超分辨空间谱估计算法,将信道响应模型引入到阵列测向估计中。利用WiFi设备多天线、OFDM技术多子载波的特点,构造出空频域平滑矩阵,通过超分辨空频域联合的MUSIC方法估计出等效的时空谱,经谱峰搜索实现多径AOA估计;然后将该模型从均匀线阵推广到任意平面阵列,实现了测向全方位无模糊的覆盖;通过分析算法测向性能,进行聚类分析后提取AOA估计结果,实现测向。其次针对时空谱估计模型中时间分辨率不足且无法估计真正的传播时延这两个问题,通过多信道联合,利用超分辨MUSIC方法实现传播时延估计。利用多径具有稀疏性的特点,另外提出了一种利用OMP算法进行稀疏重构恢复信道脉冲响应,实现更高分辨率的多径TOA估计,并根据首达波特点推断出真正的传播时延。最后给出了几种可利用信道状态信息进行WiFi室内定位的实现方法,并以单站定位为例,提出了具体的实现方法和原型架构,通过完整的系统模拟仿真分析,验证了基于空域频域联合处理的室内WiFi定位技术的可行性和有效性。
[Abstract]:With the popularity of indoor positioning requirements, various indoor positioning technology has become a hot spot. However, the indoor electromagnetic environment is complex and the wireless channel changes randomly. In the WiFi location technology, the most widely used RSSI fingerprint database matching location still has the shortcomings of low accuracy and low stability. In order to break through the limitation of fingerprint database location, a new location technology is realized by using location parameter estimation method, which combines OFDM communication technology and array direction-finding technology, using the characteristic that channel state information in WiFi has finer granularity perception environment. In this paper, the widely deployed common commercial WiFi equipment has the characteristics of multi-antenna, multi-channel and multi-subcarrier. By studying the channel response model, the basic characteristics of WiFi signal and OFDM technology, the communication technology and array direction-finding technology are combined. The spatial spectrum and time spectrum of multipath signal are recovered by the algorithm of super-resolution spatial spectrum estimation and sparse reconstruction, and the parameters of propagation delay and incidence angle of direct wave component in LOS environment are estimated. Finally, the implementation mode and prototype architecture of WiFi indoor positioning system based on channel response are given. The research contents and innovations include the following three aspects: firstly, the array direction finding, channel response model and MUSIC super-resolution spatial spectrum estimation algorithm are studied, and the channel response model is introduced into the array direction finding estimation. Using the characteristics of multi-antenna and multi-subcarrier of WiFi equipment, the space-frequency domain smooth matrix is constructed, and the equivalent space-time spectrum is estimated by the MUSIC method of super-resolution space-frequency domain, and the multipath AOA estimation is realized by spectral peak search. Then, the model is extended from uniform linear array to arbitrary plane array to realize the omnidirectional coverage without ambiguity, and by analyzing the performance of the algorithm, the AOA estimation results are extracted after clustering analysis, and the direction finding is realized. Secondly, aiming at the two problems that the time resolution is insufficient and the real propagation delay can not be estimated in the spatio-temporal spectrum estimation model, the super-resolution MUSIC method is used to realize the propagation delay estimation through the combination of multi-channels. Taking advantage of the sparseness of multipath, this paper also proposes a new method of sparse reconstruction and restoration of channel impulse response using OMP algorithm to achieve a higher resolution multipath TOA estimation, and to infer the real propagation delay according to the characteristics of the first reachable wave. Finally, several methods to realize indoor positioning of WiFi using channel state information are given. Taking the single-station positioning as an example, the specific implementation method and prototype architecture are proposed, and the complete system simulation and analysis are carried out. The feasibility and effectiveness of indoor WiFi positioning technology based on spatial frequency domain joint processing are verified.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN92
本文编号：2390419
[Abstract]:With the popularity of indoor positioning requirements, various indoor positioning technology has become a hot spot. However, the indoor electromagnetic environment is complex and the wireless channel changes randomly. In the WiFi location technology, the most widely used RSSI fingerprint database matching location still has the shortcomings of low accuracy and low stability. In order to break through the limitation of fingerprint database location, a new location technology is realized by using location parameter estimation method, which combines OFDM communication technology and array direction-finding technology, using the characteristic that channel state information in WiFi has finer granularity perception environment. In this paper, the widely deployed common commercial WiFi equipment has the characteristics of multi-antenna, multi-channel and multi-subcarrier. By studying the channel response model, the basic characteristics of WiFi signal and OFDM technology, the communication technology and array direction-finding technology are combined. The spatial spectrum and time spectrum of multipath signal are recovered by the algorithm of super-resolution spatial spectrum estimation and sparse reconstruction, and the parameters of propagation delay and incidence angle of direct wave component in LOS environment are estimated. Finally, the implementation mode and prototype architecture of WiFi indoor positioning system based on channel response are given. The research contents and innovations include the following three aspects: firstly, the array direction finding, channel response model and MUSIC super-resolution spatial spectrum estimation algorithm are studied, and the channel response model is introduced into the array direction finding estimation. Using the characteristics of multi-antenna and multi-subcarrier of WiFi equipment, the space-frequency domain smooth matrix is constructed, and the equivalent space-time spectrum is estimated by the MUSIC method of super-resolution space-frequency domain, and the multipath AOA estimation is realized by spectral peak search. Then, the model is extended from uniform linear array to arbitrary plane array to realize the omnidirectional coverage without ambiguity, and by analyzing the performance of the algorithm, the AOA estimation results are extracted after clustering analysis, and the direction finding is realized. Secondly, aiming at the two problems that the time resolution is insufficient and the real propagation delay can not be estimated in the spatio-temporal spectrum estimation model, the super-resolution MUSIC method is used to realize the propagation delay estimation through the combination of multi-channels. Taking advantage of the sparseness of multipath, this paper also proposes a new method of sparse reconstruction and restoration of channel impulse response using OMP algorithm to achieve a higher resolution multipath TOA estimation, and to infer the real propagation delay according to the characteristics of the first reachable wave. Finally, several methods to realize indoor positioning of WiFi using channel state information are given. Taking the single-station positioning as an example, the specific implementation method and prototype architecture are proposed, and the complete system simulation and analysis are carried out. The feasibility and effectiveness of indoor WiFi positioning technology based on spatial frequency domain joint processing are verified.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN92
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