Research On Laser Pulse Echo Signal Intensity Control System

In the laser ranging technology based on the measurement principle of pulse time-of-flight(TOF),it cannot meet the demand for the long distance and high precision ranging that a wide dynamic range of the laser pulse echo intensity has a great influence on the ranging accuracy.In this paper,a laser pulse echo signal intensity control system whit an optical attenuator is designed and implemented.Through this system,the laser pulse echo intensity of different amplitudes is adjusted to the same small area.Thereafter,the walk error due to changes in echo intensity is reduced and the distance measurement accuracy is improved.Firstly,an overall control system solution and the main technical parameters are determined according to the pulse parameters of a rangefinder.And analyze the relationship between system dynamic ranges and walk error.It is proposed to use a closed-loop negative feedback control system to adjust the echo intensity.Secondly,an ns-level pulse peak hold circuit is completed to detect near-echo pulse intensity.After designing optical attenuators and selecting stepper motors,an attenuator driver circuit is designed.Complete a hardware design of the control system based on microcontroller and FPGA,and write the control program.Finally,an experimental device for echo intensity control system is built to complete the test experiment.The test results of module test show that the echo intensity control system can quickly and accurately detect echo pulse intensity for repetition rate of 10 KHz and pulse width of 15ns.In addition,the test result of whole system shows that this control system meets the design requirements.