Method for evaluating influence of speckle coherence on ranging accuracy of single-photon laser radar

Abstract

The invention provides a method for evaluating the influence of speckle coherence on the ranging accuracy of a single-photon laser radar. The method comprises the steps of setting the parameters of the single-photon laser radar system, calculating the autocorrelation function of a receiving aperture of the single-photon laser radar system and the normalized covariance function on the intensity ofthe receiving aperture to calculate the speckle degree of freedom M; calculating the average signal photon number Ns according to the laser radar equation, and calculating the total noise rate Nn of the laser radar system; differentiating time through the detection probability based on the root mean square pulse width [Sigma]s of the laser pulse to obtain the detection probability density functionfs(t) of the echo signal with respect to time t, and obtaining the mean value shown in the description and the variance Var of the time when the detector detects the target point; and obtaining the influence of the speckle coherence on the ranging accuracy of the single-photon laser radar according to the drift error Ra and the random error Rp. The invention has good compatibility, can provide guidance for the system parameter design of the laser radar, improve the detection probability and reduce the ranging error as much as possible under the restraint of satisfying the false alarm probability.

Description

technical field [0001] The present invention relates to a method for evaluating ranging accuracy of pulsed ranging laser radars based on the spatial distribution of laser speckles, in particular to evaluating the transmitting system, receiving system, etc. The laser speckle spatial coherence affected by the system parameters and the initial distribution of the spot, and its influence on the ranging accuracy of the lidar is analyzed. Background technique [0002] Since the surface of the target detected by the lidar is usually "rough" with respect to the scale of the laser wavelength, the various small subsurface elements of these rough surfaces provide random phase elements for the total field observed. The primitives interfere with each other to form the final intensity. The speckle effect of the laser has no significant effect on the laser radar working in the linear system, but the influence on the statistical distribution of the photon signal received by the laser radar...

AI Technical Summary

Problems solved by technology

At present, the existing single-photon lidar ranging accuracy models and evaluation methods ignore the influence of speckle, and approximate photon events with Poisson distribution, but do not give approximate conditions related to system parameters, so it is difficult to Whether the actual ranging system satisfies the approximate conditions is evaluated, and the evaluation method considering the impact of speckle spatial correlation on the ranging accuracy is not given in the complete data

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