CN-121995388-A - Atmospheric attenuation compensation data processing system of long-distance laser radar

CN121995388ACN 121995388 ACN121995388 ACN 121995388ACN-121995388-A

Abstract

The invention relates to the technical field of laser ranging and photoelectric detection, and discloses an atmospheric attenuation compensation data processing system of a long-distance laser radar, which comprises a signal acquisition module, an atmospheric parameter calculation module, a gain control module, a timing correction module and a timing starting point offset, wherein the signal acquisition module acquires original waveform data containing a front backward scattering signal and a target echo pulse, the atmospheric parameter calculation module determines an atmospheric attenuation coefficient according to the amplitude attenuation slope of a signal segment, the gain control module adjusts the gain curve growth step length, the timing correction module determines the timing starting point offset according to the coefficient, and the gain adjustment and the offset compensation respond to the atmospheric attenuation coefficient in real time; the invention establishes a transmissivity in-situ sensing mechanism by utilizing the scattering background generated by laser echo, eliminates waveform broadening and timing starting point offset caused by medium non-uniform distribution, and improves the consistency and sensitivity of ranging.

Inventors

Zeng Liuxuan
JI BIAOJUN

Assignees

上海昱开创智能科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260309

Claims (10)

1. An atmospheric attenuation compensation data processing system for a long-range lidar, comprising: the signal acquisition module acquires original waveform data output by the detector, wherein the original waveform data comprises a target echo pulse and a back scattering signal before the target echo pulse arrives; the atmospheric parameter calculation module is used for intercepting a signal segment between a ranging zero point and a target point in original waveform data as an interface scattering signal flow, calculating the amplitude attenuation slope of the interface scattering signal flow changing along with time, and determining the atmospheric attenuation coefficient of a laser propagation path according to the amplitude attenuation slope; the gain control module is used for establishing a time-varying gain curve which increases in a nonlinear way along with the increase of the laser flight time, and adjusting the increasing slope of the time-varying gain curve in real time according to the atmospheric attenuation coefficient so as to adjust the gain of a post-stage amplifying circuit of the detector on the target echo pulse; The timing correction module is used for identifying the rising edge characteristics of the target echo pulse, determining the timing starting point offset according to the atmospheric attenuation coefficient and the slope of the rising edge characteristics and correcting the original ranging result through a preset nonlinear mapping rule; The atmospheric parameter calculation module outputs the determined atmospheric attenuation coefficient to the gain control module and the timing correction module in real time, and the gain control module adjusts the time-varying gain curve and the timing correction module determines the timing starting point offset, and the gain control module and the timing correction module respond to the change of the atmospheric attenuation coefficient in real time to form a logic closed loop for sensing environmental characteristics and correcting measurement deviation in a single pulse sampling period.
2. The system according to claim 1, wherein the atmospheric parameter calculation module extracts a local signal in a preset window before a target echo pulse rising edge trigger time in the backward scattering signal, calculates a level variation of the leveling average amplitude of the local signal with respect to the interface scattering signal, and inverts a local optical transmittance on the laser propagation path according to the level variation, thereby correcting an atmospheric attenuation coefficient to eliminate a measurement error caused by a medium concentration mutation at a near-target point position.
3. The atmospheric attenuation compensation data processing system of long-distance laser radar of claim 1, wherein the atmospheric parameter calculation module comprises a sampling statistics unit for counting the flip density of least significant bits of the original waveform data within a preset time window , wherein, The waveform reconstruction unit is used for reconstructing the waveform according to the turnover density Quantization step length with detector analog-to-digital converter Recovering a sub-quantized envelope curve The calculation formula is as follows: wherein, the atmospheric parameter calculation module calculates the envelope curve according to the sub-quantization Determining the atmospheric attenuation coefficient by using the time-dependent gradient, and extracting the intrinsic thermal noise of the detector to be lower than the quantization step length Is used for the scattering signal amplitude characteristic of the (a).
4. The system for compensating for atmospheric attenuation of long range lidar of claim 1, further comprising an ambient noise monitoring module for acquiring an output signal of the detector during a predetermined time slot prior to the laser pulse transmission to obtain an intrinsic thermal reference An offset stripping module for obtaining real-time background noise signal in the original waveform data Will be real-time background noise signal With intrinsic thermal references Performing differential processing to extract pure atmospheric scattering component Wherein the atmospheric parameter calculation module is based on pure atmospheric scattering component And correcting the atmospheric attenuation coefficient, and stripping the temperature drift component of the detector.
5. The system of claim 1, further comprising a local gradient monitoring module for extracting backscatter signals within a predetermined window before triggering a target echo pulse front and calculating a slope of energy decline of the backscatter signals The atmospheric parameter calculation module is used for calculating the gradient according to the energy drop Rising edge slope of target echo pulse Determining interface coupling factors The calculation formula is as follows: wherein the timing correction module is based on the interface coupling factor And carrying out secondary weight correction on the timing starting point offset.
6. The system of claim 1, wherein the atmospheric parameter calculation module divides the backscatter envelope before the target echo pulse into micro-path elements and calculates the amplitude variance of each micro-path element Amplitude variance of gain control module between adjacent two micro path units And (3) injecting pulse gain weights for the time-varying gain curve at positions where the rate of change exceeds a preset threshold value so as to compensate the heterogeneous medium layers in the path.
7. The atmospheric attenuation compensation data processing system of a long-distance laser radar according to claim 1, wherein the atmospheric parameter calculation module calculates near-field expected peak energy according to an atmospheric attenuation coefficient determined by a preamble sampling period, and the gain control module outputs a gain attenuation instruction which is inversely related to the near-field expected peak energy to a bias voltage adjustment link of the detector in a preset near-field time slot after laser pulse emission, so that original waveform data is maintained in a linear dynamic range of the detector.
8. The system for compensating for the atmospheric attenuation of the long-distance laser radar according to claim 1, further comprising a target attribute identification module, wherein the target attribute identification module is used for extracting an envelope residual signal in original waveform data, distinguishing the interference between an atmospheric medium and a moving entity according to the energy distribution characteristic of the envelope residual signal in a frequency domain, and when the interference of the moving entity is judged, the gain control module is used for keeping the correction amount corresponding to the current atmospheric attenuation coefficient unchanged and shielding the correction of the gain adjustment by the moving entity.
9. The system of claim 1, wherein the gain control module employs a gain compensation function that increases exponentially with increasing laser flight time, and wherein an exponential growth coefficient of the gain compensation function is positively correlated with the atmospheric attenuation coefficient to maintain a weak echo signal at a far end of the ranging range within a dynamic identification window of the detector.
10. The system of claim 1, wherein the timing correction module stores a timing error look-up table model, the timing correction module uses a rising edge slope of the target echo pulse and an atmospheric attenuation coefficient as input variables of the timing error look-up table model, determines a deviation value of the trigger time with respect to the pulse energy center, and uses the deviation value as a timing start offset.

Description

Atmospheric attenuation compensation data processing system of long-distance laser radar Technical Field The invention relates to an atmospheric attenuation compensation data processing system of a long-distance laser radar, and belongs to the technical field of laser ranging and photoelectric detection. Background The current laser ranging sensor acquires target position information by utilizing the flight time of laser pulses, is widely applied to automatic driving and industrial measurement systems, and is used for transmitting laser pulses in free space under the influence of atmospheric aerosol absorption and scattering to generate energy attenuation and pulse envelope broadening distortion, and the conventional method for maintaining a measurement range relates to increasing laser emission power or improving detection sensitivity. Under the condition of fluctuation of environmental visibility, the hardware gain is improved to enable a detector to be saturated and limited by human eye safety power, for example, china patent with publication No. CN107167792A discloses an atmospheric laser communication machine with a ranging function and a ranging method thereof, a ranging crystal oscillator is additionally arranged in a communication circuit, a mode selection switch is utilized to switch between communication and ranging states, the distance is measured by calculating pulse round trip delay, the ranging process depends on preset fixed delay parameters, a working mode is required to be manually or limited, real-time sensing on-line compensation cannot be carried out on dynamic delay generated by system time base deviation, device aging temperature drift and channel fluctuation under complex working conditions, the control thought lacking flexible regulation capability is difficult to meet strict requirements of high-precision industrial efficiency on instantaneity and self-adaptability, an external meteorological sensor is used for processing and correcting an improved path after acquiring local parameters, and the measurement result is difficult to generate centimeter-level even meter-level random fluctuation along with meteorological conditions due to the fact that external monitoring data is difficult to characterize instantaneous nonuniform medium distribution on a long-distance path through which laser pulses are triggered. Therefore, how to utilize the ranging system to receive the original waveform envelope to realize the in-situ inversion of the transmission path characteristics, and cooperatively complete the dynamic compensation of energy and the correction of timing deviation on the premise of not depending on additional perception hardware becomes the technical problem to be solved by the invention. Disclosure of Invention In order to solve the problems in the background technology, the technical scheme of the invention is as follows, an atmospheric attenuation compensation data processing system of a long-distance laser radar comprises: the signal acquisition module acquires original waveform data output by the detector, wherein the original waveform data comprises a target echo pulse and a back scattering signal before the target echo pulse arrives; the atmospheric parameter calculation module is used for intercepting a signal segment between a ranging zero point and a target point in original waveform data as an interface scattering signal flow, calculating the amplitude attenuation slope of the interface scattering signal flow changing along with time, and determining the atmospheric attenuation coefficient of a laser propagation path according to the amplitude attenuation slope; the gain control module is used for establishing a time-varying gain curve which increases in a nonlinear way along with the increase of the laser flight time, and adjusting the increasing slope of the time-varying gain curve in real time according to the atmospheric attenuation coefficient so as to adjust the gain of a post-stage amplifying circuit of the detector on the target echo pulse; The timing correction module is used for identifying the rising edge characteristics of the target echo pulse, determining the timing starting point offset according to the atmospheric attenuation coefficient and the slope of the rising edge characteristics and correcting the original ranging result through a preset nonlinear mapping rule; The atmospheric parameter calculation module outputs the determined atmospheric attenuation coefficient to the gain control module and the timing correction module in real time, and the gain control module adjusts the time-varying gain curve and the timing correction module determines the timing starting point offset, and the gain control module and the timing correction module respond to the change of the atmospheric attenuation coefficient in real time to form a logic closed loop for sensing environmental characteristics and correcting measurement deviation in a single pulse sampling peri