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激光多普勒测速仪(LDV)能够实现载体速度的高精度测量,从而满足航空航天领域对高精度导航的需求。目标速度测量是建立在回波信号成功检测的基础上进行的,因此微弱多普勒信号检测是LDV的关键技术。根据光频段噪声频谱特性,提出了对有用信号频率进行带阻滤波、利用剩余噪声强度估计总体噪声强度的方法,设计了频域内基于噪声强度估计的自适应阈值信号检测算法。通过与传统的固定阈值算法的对比仿真和实验,表明该方法具有更好的探测性能,能够在保持较低恒定虚警概率条件下实现对高于信噪比为-9 d B信号的完全检测,具有抵抗噪声强度的起伏变化、算法简单、适用性强等特点。
Laser Doppler velocimetry (LDV) enables high-precision measurement of carrier velocities to meet the high-precision navigation needs of aerospace. The target velocity measurement is based on the successful detection of echo signals. Therefore, weak Doppler signal detection is the key technology of LDV. According to the spectral characteristics of optical frequency band, a method of band-reject filtering the useful signal frequency and estimating the overall noise intensity by the residual noise intensity is proposed. The adaptive threshold signal detection algorithm based on the noise intensity estimation is designed in the frequency domain. Compared with the traditional fixed threshold algorithm, the simulation and experiment show that this method has better detection performance and can achieve full detection of SNR higher than -9 dB signal while keeping the probability of low constant false alarm , With the ups and downs against the noise intensity changes, the algorithm is simple, applicability and so on.