UWB无线定位系统研究及FPGA实现.pdf

摘要
摘要
脉冲超宽带(IR-UWB)技术有良好的时间分辨能力,能实现通信与定位的融合,
是短距高速无线通信的热门候选方案之一。本文的研究内容为室内环境下的无线定位
系统的 TOA 估计算法和接收机基带设计。
基于能量检测的TOA估计算法由于不需要在接收端直接对接收信号进行高速采
样,也不需要产生精确的匹配模板,能够降低硬件的复杂度而得到广泛的应用,但是
它依旧需要A/D采样和大量的计算,在低信噪比条件下性能不理想,针对上述缺点,
本文采用了一种基于锁相环的TOA估计算法,它利用了锁相环对噪声有很强的抑制作
用的特性,可以轻松地实现对脉冲信号到达时间估计。对算法进行计算机仿真和电路
验证,结果表明,在低信噪比条件下,锁相环TOA估计算法相比MES算法有很小的估
计方差,有很强的鲁棒性,而且结构简单、对硬件性能要求低。
基于锁相环的TOA估计算法是一种有偏估计,在NLOS环境下,由于多径信号密
集,基于锁相环的TOA估计算法有较大的估计偏差,所以不适用于NLOS环境。针对
上述问题,本文提出了一种基于迟、早支路不平衡的延迟锁相环TOA估计算法,它通
过减小延迟支路的增益,使得锁相环锁定的位置更加接近信号的直达路径,计算机仿
真表明,在NLOS条件下,迟早支路不平衡的延迟锁相环TOA算法比锁相环TOA估计
算法有更小的估计偏差,可以在NLOS环境下使用。
本文还介绍了接收机基带的组成,基带的时差计数器采用了数字移相计时法,该
方法能够由FPGA实现而且有较高的计时精度,有效降低了设计的复杂度。此外,还
详细介绍了RS-232串口发送器、数据缓存接口的设计,并给出了相应的时序仿真结果。
最后对定位系统进行了联合测试,测试结果表明,本文设计的超宽带无线定位系
统有较好的定位精度,定位误差在在15~30cm之间,而且系统简单,成本低,有工程
应用价值。


关键词:超宽带;定位;到达时间估计;锁相环;FPGA



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万方数据
摘要
Abstract
Impulse Radio Ultra-WideBand technology, which can realize the integration of
communications and positioning because of its good time-resolution capacity, is one of the
top candidate solutions for short-range munication. This paper focus on TOA
estimation algorithm and baseband design of receiver for indoor environmental wireless
positioning system.
TOA estimation algorithm based on energy detection, which does not need direct
high-speed sampling to the received signal or generation of precise matching-template at
the receiving end, can reduce the plexity and has been used widely. But TOA
estimation algorithm still needs A/D sampling and a large number of calculation, which
makes its performance is poor at low SNR conditions. A PLL-based TOA estimation
algorithm was proposed in this paper to resolve above-mentioned ing. Compared
with MES algorithm, the results of simulations and circuit test show that the TOA
estimation algorithm base on PLL has very small estimated variance, strong robustness,
simple structure and low requirement to ha