脉冲定时误差会使测距精度恶化,为此,提出了一种基于循环平稳随机序列的脉冲激光测距方案。该方案首先将回波脉冲定时信号映射在周期基准信号上,由此构造出一个循环平稳的随机序列,将对脉冲定时时间的测量转化为对循环平稳随机序列的参数估计。该方法利用了循环平稳随机过程在时间上呈现为周期性平稳变化的特征,从携带时间抖动等误差的测量数据中高精度地估计参数,从而获得高精度的目标距离。为了获得循环平稳随机序列测量数据,提出了一种遍历欠采样方法,以解决在采样频率与信号频率相差很大的条件下进行等效等间隔采样的困难。以此原理研制出的脉冲激光测距仪具有精度高、原理结构简单等优点,测试后可知,在激光出瞳平均功率为1 mW的条件下,当信噪比为10时,无合作目标测程为300 m,测距精度为±(2 mm+2×10 -6D)。

To avoid deterioration in the ranging accuracy caused by pulse-timing errors, a pulsed laser ranging method using cyclostationary random sequences is proposed. In this method, echo pulse-timing signals are mapped onto periodic reference signals to construct cyclostationary random sequences, which converts measurements of pulse-timing moments into parameter estimation of these sequences. The use of periodic stationary changes in time for cyclostationary stochastic processes enables the accurate estimation of parameters from the measurement data with timing jitter errors. High-precision target distances can then be obtained. An ergodic undersampling method is also proposed to overcome the difficulty of using equivalent and equally-spaced sampling for obtaining the measurement data of cyclostationary random sequences when the sampling and signal frequencies are very different. A pulsed laser rangefinder based on these principles is developed with the advantages of high accuracy and simple structure. When the laser exit pupil average power is 1 mW and the signal-to-noise ratio is 10, tests show that the non-cooperative target range is 300 m and the range accuracy is ±(2 mm+2×10 ^-6D ).