Research On Key Technologies Of Integrated Multi-line LADAR

Pulsed LADAR has been widely used in terrain mapping,intelligent robot,unmanned and automatic driving,etc.,due to its advantages of distance ranging,high efficiency and high relative accuracy.Traditional LADAR detection systems are designed with discrete components,which have problems such as large volume,high cost and poor reliability.In order to improve the degree of integration and ranging accuracy,the key technologies of integrated and high precision LADAR detection system are studied.Based on System In a Package technology,an integrated 16-element LADAR analog front-end micromodule was designed.This module integrated a 16-element Avalanche Photon Diode array detector,a single chip with multi-channel LADAR analog front-end readout circuit,a temperature sensor,a narrowband filter,a substrate,and a Thermoelectric Cooler,which realized the integration of detection,processing and temperature control.In view of the parasitic effect of the substrate interconnection and the influence of the spatial position of each circuit on the temperature distribution,the simulation of signal integrity and the simulation temperature field distribution were carried out by using Advanced Design System software and ANSYS ICEPAK software,and the optimization Design of the multi-chip packaging substrate was completed.Aiming at the problem that the main parameters of photodetector are closely related to the working temperature,a high precision temperature control circuit module based on Thermoelectric Cooler was designed.The experimental results show that the noise level of the integrated microcomponent is reduced by at least 32% compared to the non-integrated component,the overall bandwidth of the microcomponent can be up to 190 MHz,the pulse signal crosstalk ratio between channels is less than 0.5%.Aiming at the problem of low ranging accuracy in the centroid algorithm of LADAR echo signal processing,an improved trapezoidal approximate centroid algorithm was proposed.The algorithm can correct the echo pulse positioning,improve the echo signal processing ability,and has the characteristics of high precision and easy to implement in hardware.Firstly,the positioning correction algorithm was designed to complete the correction of pulse positioning.Secondly,the basic principle of pulse centroid algorithm was analyzed,and the calculation formula of pulse centroid in digital domain was studied.Combined with the positioning correction algorithm,the improved trapezoidal approximate centroid algorithm was designed.The simulation results show that the maximum standard deviation of ranging error is 2.4 cm,which is 19.3% lower than the mainstream centroid algorithm.Finally,the hardware implementation of the algorithm was completed based on FPGA.The experimental results show that the maximum standard deviation of the ranging error is 2.8 cm.