Multi-edge trigger time identification method and pulse type laser ranging method

Abstract

The invention discloses a multi-edge trigger time identification method used for pulse type laser ranging. The multi-edge trigger time identification method is characterized in that a threshold comparator receives a laser ranging echo signal, wherein the rising edge and the falling edge of the echo signal simultaneously trigger the threshold comparator by same threshold voltage; the rising edge ofthe echo signal triggers the threshold comparator in the first time; the falling edge of the echo signal triggers the threshold comparator in the second time; and the average value of the first timeand the second time is taken as time for the threshold comparator to receive the echo signal. According to the multi-edge trigger time identification method disclosed by the invention, the contradiction problem that system stability and triggered time clock errors cannot be simultaneously obtained can be fundamentally solved.

Description

technical field [0001] The invention relates to the field of photoelectric ranging, in particular to a multi-edge trigger time identification method and a pulsed laser ranging method using the time identification method. Background technique [0002] The basic principle of pulsed laser ranging is: the laser emitting device emits a laser pulse (referred to as "initial wave signal") to the measured object at the ranging point, and the echo signal after the light pulse is reflected by the measured object is received by the receiving device. Receiving, according to the time difference between the time when the receiving device receives the echo signal and the time when the laser emitting device emits the initial wave signal, the distance between the ranging point and the measured object is measured. [0003] The time accuracy of the echo signal received by the receiving device directly affects the ranging accuracy. At present, the time discrimination method is generally used to ...

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Problems solved by technology

[0004] The light intensity of the echo signal after the same initial wave signal is reflected by different objects to be measured is divided into strong and weak points. On the other hand, as the distance increases, the echo signal received by the receiving device will also decrease. The rising edge of the light is different, such as figure 1 , 2 As mentioned above, the echo signal of strong and weak light is triggered by the threshold level, which will cause a clock error Δt. This clock error will cause a centimeter or even decimeter-level time error. To reduce the clock error, it is necessary to set the threshold voltage as close as possible to the base noise. , so that the clock error Δt will be reduced as much as possible, but it will bring another problem, the noise of the system is easy to trigger the counter by mistake

like figure 1 As shown, the threshold voltage is high, the system is not easy to be falsely triggered, and the stability is good, but the clock error Δt between strong and weak signals is large, resulting in poor system accuracy

like image 3 As shown, the threshold voltage is low, and the trigger error Δt between strong and weak signals is small, but the low threshold voltage is easily triggered by glitches and ripples caused by the system power supply or the environment, and the system stability is not good

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