基于802.11p协议改进的车辆测距算法

随着交通事故的增长和智能交通的发展,基于车辆碰撞预警和交通管理的新服务引起了广泛关注。目前,基于全球导航卫星系统(GNSS)的定位技术已应用到车辆环境中。由于GNSS存在的盲区(例如森林,隧道等)会导致定位结果不准确,在车辆自组织网络(VANET)中,提出了基于IEEE 802.11p标准的定位方法。提出了用IEEE 802.11p短前导码的高效到达时间(TOA)或测距估计方法,以降低低信噪比(SNR)的影响。使用了自相关和互相关(混合相关)来执行到达时间(TOA)估计,对相关结果进行间隔求和的方法以达到更精确定位的目的。在加性高斯白噪声(AWGN)信道中的仿真结果表明:在低SNR条件中,提出的测距方法相比传统方法达到了更高的精度。

Improved Vehicle Ranging Algorithm Based on 802.11p Protocol

As the growth of traffic accidents and the development of intelligent transportation,new services like vehicle collision warning and traffic management are required.Nowadays,many location techniques based on the global navigation satellite system(GNSS)have been used in vehicle environment.In view of inaccuracy positioning results in GNSS-dark area such as forest,tunnel,etc,high-mobility positioning methods used IEEE 802.11p standard in vehicular ad hoc networks(VANETs)should be developed.In this paper,we propose an efficient TOA or ranging estimation method using IEEE 802.11p short preamble in order to mitigate the influence of low signal noise ratio(SNR).At first,the TOA estimation is performed using autocorrelation and cross-correlation(auto-cross).Then,an approach is presented for finding the accurate time offset.Simulation results,in an additive white Gaussian noise(AWGN)channel,indict that the proposed ranging method achieves superior accuracy than traditional methods even in low SNR conditions.