光学与光电技术, 2013, 11 (3): 10, 网络出版: 2013-10-29
相干多普勒测风激光雷达低信噪比区域回波信号的估计方法
Doppler-Shift Estimation Method in Low SNR Region for Coherent Doppler Lidar
相干激光雷达 多普勒频移估计 非线性自适应多普勒频移估计 周期图最大值法 coherent doppler lidar Doppler-shift estimation novel nonlinear adaptive Doppler-shift estimation periodogram
摘要
相干多普勒测风激光雷达通常会采用周期图最大值法(PM)提取不同距离门信号的多普勒频移(对应风速)信息。由于噪声和相干效率的影响,个别距离门信号会出现信噪比(SNR)突然降低的情况,从而导致系统的探测概率降低,影响系统整体的探测性能。为了解决个别距离门信号多普勒频移的错误估计问题,提出了一种新的非线性自适应多普勒频移估计方法。该方法利用风速的连续性,标定错误距离门,并自适应地利用强信噪比区域的多普勒频移统计数据来弥补信噪比变差而出现的估计错误。分别利用了仿真模型和一套1.54 μm全光纤相干激光雷达系统获得了风场测量数据,对比了使用该技术前后反演得到的风速趋势,证明该方法能够有效地解决上述问题。
Abstract
The PM estimator is the most widely used method in Doppler-Shift estimation. According to the theoretical simulation, the detection probability of the system deteriorates rapidly as the SNR decreases. In order to improve the quality of Doppler-shift estimation, a novel nonlinear adaptive Doppler-shift estimation method(NADSEM) is established. NADSEM compensates this deterioration by adaptively utilizing the statistics of Doppler-shift estimates in strong SNR regime. The data of wind velocity are acquired by a 1.54 μm all fiber coherent Doppler lidar system, then used by NADSEM to estimate the Doppler-shift frequency. The authenticity of NADSEM is established by comparing the trend of wind parameters with and without NADSEM applied to the lidar return data.
靳笑晗, 汪岳峰, 竹孝鹏, 刘继桥, 刁伟峰, 陈卫标. 相干多普勒测风激光雷达低信噪比区域回波信号的估计方法[J]. 光学与光电技术, 2013, 11(3): 10. JIN Xiao-han, WANG Yue-feng, ZHU Xiao-peng, LIU Ji-qiao, DIAO Wei-feng, CHEN Wei-biao. Doppler-Shift Estimation Method in Low SNR Region for Coherent Doppler Lidar[J]. OPTICS & OPTOELECTRONIC TECHNOLOGY, 2013, 11(3): 10.