A frequency-modulated continuous-wave laser ranging method using low-duty-cycle linear-frequency-modulated (LFM) signals is proposed. A spectrum consisting of a dense Kronecker comb is obtained so that the frequency of the beat signal can be measured with finer resolution. Since the dense comb is provided, super-resolved laser ranging can be achieved using a single-parametric frequency estimation method. Therefore, the run times of the estimation are reduced which promises real-time applications. A proof-of-concept experiment is carried out, in which an LFM signal with a bandwidth of 5 GHz and a duration of 1 µs is used. The duty-cycle of the LFM signal is 10%. The time delay of a scanning variable optical delay line is obtained in real time from the frequency of the highest comb tooth, of which the measurement resolution is 20 ps. Moreover, a single-parametric nonlinear least squares method is used to fit the envelope so that the time delay can be estimated with super-resolution. The standard deviation of the estimation displacements is 2.3 ps, which is 87 times finer than the bandwidth-limited resolution (200 ps). Therefore, the variation of the time delay can be precisely monitored. The proposed method may be used to achieve real-time high-resolution laser ranging with low-speed electronic devices.

中文翻译：

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利用低占空比信号进行调频连续波激光测距，用于实时超分辨测距

提出了一种使用低占空比线性调频（LFM）信号的调频连续波激光测距方法。获得了由密集的Kronecker梳组成的频谱，从而可以以更高的分辨率测量拍信号的频率。由于提供了密集的梳子，因此可以使用单参数频率估计方法实现超分辨激光测距。因此，减少了估计的运行时间，保证了实时应用。进行了概念验证实验，其中使用了带宽为5 GHz，持续时间为1 µs的LFM信号。LFM信号的占空比为10％。扫描可变光学延迟线的时间延迟是从最高梳齿的频率实时获得的，其测量分辨率为20 ps。此外，使用单参数非线性最小二乘法来拟合包络，以便可以以超分辨率估算时间延迟。估计位移的标准偏差为2.3 ps，这是带宽受限分辨率（200 ps）的87倍。因此，可以精确地监视时间延迟的变化。所提出的方法可用于通过低速电子设备实现实时高分辨率激光测距。