导　　师： 秦华标

学科专业： 080902

授予学位： 硕士

作　　者： ;

机构地区： 华南理工大学

摘　　要： 无钥匙系统是汽车电子一个新的标志，也是车辆防盗技术的必然发展趋势。基于无线定位的钥匙位置检测技术，是无钥匙系统的关键技术之一。对无钥匙系统的定位算法进行研究，不仅关系电子系统能否实现对车辆的智能控制，而且关系到车辆电子系统的安全性。同时，也对无线传感器网络的研究有一定的帮助。 基于RSSI技术/(Received signal strength indicator/)的无线定位算法，它将接收到的信号强度利用信号衰减模型转化为距离，从而实现定位。是一种功耗低、硬件要求低、成本低的无线定位技术，也是目前无线定位技术的主流。本文是通过对无线定位技术的分析与无钥匙系统基本理论的研究展开的。通过对比总结，文中采用了基于RSSI的定位算法。在深入理解电磁波传播原理后，通过传输线理论计算得到了433MHZ信号对汽车座椅的透射与反射能量比，构建了433MHZ信号在车内环境下的衰减模型，并对这一衰减模型与自由空间模型进行仿真对比，通过实测观察，证明了这一模型的有效性。 由于基于测距的无线定位算法在定位计算过程中存在误差累积，在解决了模型有效性问题后，减小这种计算误差是十分必要的。本文从最小二乘法出发，得到系数矩阵对定位精度存在影响的结论，进而优化这个矩阵，进一步提高了计算的精确度。根据RSS值容易受环境因素影响，可能存在较大偏差的问题，在算法上考虑了各种约束条件，对明显偏离的值进行过滤，一定程度上保证了数值的真实度。针对加权质心算法数据利用不充分的缺点，引入了二次加权因子，进行了第二次加权，从而进行第二次位置估计，对定位结果进行了进一步的修正，使得定位精度达到了既定要求。 最后，在MATLAB平台上对这种算法与加权质心算法以及最小二乘法进行了仿� Keyless System is not only a new symbol in automotive electronics, but also aninevitable development tendency in Vehicle Anti-theft technology. The key position detectiontechnology built upon Wireless Location is one of the pivotal technologies in Keyless System.The research for location algorithm of Keyless System concerns whether the electronicsystem can achieve intelligent control of the vehicle, and related to vehicle electronic systemsecurity. It also contributes to the study of Wireless Sensor Network at the same time. The Wireless Location Algorithm based on RSSI/(Received signal strength indicator/)technology, will use the Signal attenuation model to transform the receiving signal strengthinto the distance, thereby to realize locating. It is the mainstream of Wireless Locationtechnology currently, which has low power consumption, low hardware requirements and lowcost. This paper is carried out by analyzing Wireless Location technology and basic theory ofKeyless System. By comparing the summary of the research, this paper adopted the locationalgorithm based on RSSI. Under the further understanding of the electromagnetic wavepropagation theory, this paper uses the transmission line theory to calculate the433MHZsignal transmission and reflection energy ratio on the car seat, andbuilds a433MHZ signal attenuation model in the vehicle environment, then comparesthis attenuation model and the model of free space by simulation. The measured observationproves the validity of this model. Since the Wireless Location algorithm based on distance measurement exist thecumulative error during the process of position calculation, it is very necessary to reduce thecumulative error after solving the problem of the validity of the model. This essay utilizes theleast squares method to obtain the conclusion that the coefficient matrix impacts the accuracyof positioning, then optimizes the matrix and improves the accuracy of the calculation.Considering the RSS values are affected by environmental factors, it may be unsta

关 键 词： 无钥匙系统 定位算法 加权质心算法

领　　域： [电子电信] [电子电信]