激光多普勒测速系统自适应阈值检测算法

信号检测是激光多普勒测速(LDV)系统实现高精度的关键技术,针对LDV中微弱多普勒信号的检测,本文从噪声在频域中的统计特性出发,对多普勒信号进行带阻滤波,结合雷达的恒虚警(CFAR)检测技术,设计了基于频域的单元平方和自适应阈值检测算法以解决在低信噪比(SNR)的环境中LDV的信号检测问题,提高LDV的信号探测能力,同时降低其虚警概率。仿真与实验的结果表明:该算法与固定阈值相比可以在SNR为-12 d B时实现信号的完全检测,保持低虚警概率,运算简单,工程适用性强。

Adaptive threshold detection algorithm of LDV system

Signal detection is the key technology for the high precision of laser Doppler velocimetry (LDV) system.In order to achieve the accurate detection of the weak Doppler signal in LDV,we carried out a band-stop filtering toward the Doppler signal on the ground of the statistical characteristics of the noise in frequency domain.Combined with the constant false alarm rate (CFAR) detection technology of radar,an algorithm of adaptive threshold detection based on the sum of unit square in frequency domain is proposed so as to address the difficulty in signal detection within the atmosphere of low signal noise ratio (SNR),improving the detection performance and decreasing the probability of false alarm.Compared with the fixed threshold through simulations and experiments,this algorithm boasts the advantage of complete detection under the circumstance of SNR-12 dB while maintaining a relatively lower false alarm rate and simple operation as well as great applicability.