基于延迟锁相环的到达时间估计算法

超宽带脉冲信号具有高时间分辨能力,能达到厘米级的定位精度。目前,脉冲超宽带测距定位系统中普遍采用基于能量检测的非相关到达时间(TOA)估计算法的性能通常受限于阈值门限和估计偏差。该文在原先锁相环方案基础之上引入延时迟支路和衰减因子,提出了一种易于实现的基于延迟锁相环的TOA估计算法。通过在迟支路中设置不同的衰减因子,仿真结果表明,在IEEE802.15.4a4种信道模型CM1~CM4中,新算法均能有效提升测距定位精度,即缩短了首达路径与锁相环稳态锁定点之间的时差,其估计偏差最低可降至原有方案的1/10。

Time of Arrival Estimation Algorithm Based on Delay Locked Loop

The impulse radio ultra wideband (IR UWB) signal has high time resolution, which can achieve centimeter level positioning accuracy.The non related time of arrival (TOA) estimation algorithm based on energy detecting is widely implemented in the IR UWB ranging positioning system,the ranging accuracy depends on its threshold and its estimation. An easy to implement TOA estimation algorithm using delay locked loop(DLL) is presented in this article by inducing delay branch and attenuation factor to original scheme based on phase locked loop(PLL).By use of attenuation factor,the simulation results show that the proposed scheme has improved ranging positioning accuracy efficiently in all four channel model of IEEE802.15.4a (CM1 CM4).The new algorithm shortens the time lag between first arrival path and DLL steady locking point and the obtained estimation error can be decreased down to 1/10 of the original scheme.