A Method and System for Acquiring Glacier Ground Laser Scanning Data Based on Weather Regulation

Abstract

This invention relates to the field of positioning technology and discloses a method and system for acquiring glacier ground laser scanning data based on weather regulation. The method includes: emitting laser pulses towards the scanning area along the elevation angle direction of the laser device, and encapsulating the distance and intensity received when the laser pulses return into a parameter sequence; acquiring the snow albedo of the glacier surface in the scanning area at the current moment, and determining a criterion for identifying near-ground snow fog interference peaks based on the snow albedo; identifying echo peaks belonging to the glacier surface based on the parameter sequence; and identifying near-ground snow fog interference peaks located in front of the echo peaks and with an intensity value exceeding the echo peaks according to the criterion. This invention can solve the problems of relying on post-processing filtering and failing to actively avoid interference layers, resulting in discontinuous long-term sequence observations and low operational efficiency.

Description

Technical Field

[0001] This invention relates to the field of positioning technology, and in particular to a method and system for acquiring glacier ground laser scanning data based on weather regulation. Background Technology

[0002] Glacier areas are prone to forming near-ground snow fog layers. Suspended snow crystals produce strong Mie scattering, forming interference echo peaks that precede the actual glacier surface. Existing technologies do not establish interference judgment criteria based on snow albedo, making it difficult to distinguish between effective echoes and near-ground snow fog interference peaks. This often results in problems such as laser main lobe being blocked by snow fog layers, point cloud distortion, ranging jumps, and missing effective data, which seriously reduce the integrity and accuracy of 3D reconstruction of the glacier surface.

[0003] Secondly, existing acquisition methods generally lack real-time perception and adaptive control of the dynamic evolution of near-ground snow and fog, fail to predict the vertical diffusion trend of the snow and fog layer through cold radiation inverse temperature gradient, and fail to correct the interference judgment threshold and scanning posture; they rely more on post-processing filtering and do not actively avoid interference layers, resulting in discontinuous long-term series observations and low operational efficiency. Summary of the Invention

[0004] This invention provides a method and system for acquiring glacier ground laser scanning data based on weather regulation, the main purpose of which is to address the problems raised in the background section above.

[0005] To achieve the above objectives, the present invention provides a method for acquiring glacier surface laser scanning data based on weather regulation, comprising: S1. Along the pitch angle direction of the laser device, a laser pulse is emitted into the scanning area, and the distance and intensity received when the laser pulse returns are encapsulated into a parameter sequence. The snow albedo of the glacier surface in the scanning area at the current moment is collected, and the judgment criteria for identifying near-ground snow fog interference peaks are determined in combination with the snow albedo. S2. Based on the parameter sequence, identify the echo peaks belonging to the glacier surface. According to the judgment criteria, identify the near-ground snow fog interference peaks that are in front of the echo peaks and whose intensity values ​​exceed the echo peaks. Determine the radial distance corresponding to the near-ground snow fog interference peaks as the upper boundary thickness of the near-ground snow fog layer in the scanning area. S3. Based on the thickness of the upper boundary and the installation height of the laser device, design the minimum pitch angle that allows the main lobe of the laser device to avoid the near-ground snow and fog layer; S4. During the horizontal reciprocating scanning process of the laser device, the cold radiation inversion gradient above the glacier surface is collected. The vertical diffusion trend of the near-ground snow fog layer is predicted based on the inversion gradient. The judgment criterion is corrected based on the vertical diffusion trend. At the same time, the near-ground snow fog interference peak is monitored for dissipation based on the second corrected judgment criterion. S5. When the near-ground snow fog interference peak has not dissipated, raise the pitch angle of the laser device to the minimum pitch angle to obtain the actual pitch angle value; S6. Complete the acquisition using the actual pitch angle value, and spatially stitch the acquired point cloud data with the pitch angle before lifting to obtain a continuous point cloud.

[0006] Preferably, the step of collecting the snow albedo of the glacier surface in the scanned area at the current moment, and combining the snow albedo to determine the criteria for identifying near-ground snow fog interference peaks, includes: Using a pre-set portable spectroradiometer, select several snow sampling points within the scanning area, and sequentially collect the downward solar incident irradiance and upward snow reflected irradiance at each sampling point; The ratio of the downward solar incident irradiance to the upward snow reflected irradiance is taken as the spectral albedo of each sampling point; Calculate the average value of the spectral albedo to obtain the snow albedo of the scanned area; By combining the operating wavelength of the laser device with the snow albedo, the theoretical echo intensity benchmark of the laser pulse on the glacier surface under the current snow cover condition is calculated. Using the theoretical echo intensity benchmark, the criteria for determining near-ground snow and fog interference peaks are established.

[0007] Preferably, the step of identifying echo peaks belonging to the glacier surface by combining the parameter sequence, and identifying near-surface snow fog interference peaks located in front of the echo peaks and with intensity values ​​exceeding the echo peaks according to the judgment criteria, includes: The parameter sequence received by the laser device is acquired, and the discrete sequences of distance and intensity are extracted from the parameter sequence; Correct and remove the background noise in the discrete sequence to obtain the net echo intensity sequence; Retrieve echo peaks that match the corresponding morphological characteristics of the glacier surface from the net echo intensity sequence, and determine the peak value of the echo peaks; Using the radial distance of the echo peak as the dividing boundary, the front end interval of the net echo intensity sequence is taken as the search range of near-ground snow and fog interference peaks; Based on the aforementioned criteria, near-ground snow and fog interference peaks are identified from the search range.

[0008] Preferably, determining the radial distance corresponding to the near-ground snow and fog interference peak as the upper boundary thickness of the near-ground snow and fog layer in the scanning area includes: Verify the waveform characteristics of the near-ground snow and fog interference peak in the net echo intensity sequence; Based on the waveform characteristics, it was confirmed that the near-ground snow fog interference peak originated from Mie scattering of suspended snow crystal particles within the near-ground snow fog layer, rather than from other non-target scattering sources. Based on the current pitch angle of the laser device, the radial distance is decomposed by slant range projection in the vertical direction to obtain the vertical elevation component of the interference peak relative to the horizontal plane where the laser device is located. The vertical elevation component is defined as the upper boundary thickness of the near-ground snow and fog layer.

[0009] Preferably, the step of designing the minimum pitch angle that allows the main lobe of the laser device to avoid the near-ground snow and fog layer based on the thickness of the upper boundary and the installation height of the laser device includes: The upper boundary thickness is converted into a radial safety avoidance lower limit along the scanning direction of the laser device; The laser beam divergence angle and near-field Rayleigh length are introduced from the factory-issued optical parameters of the laser device. Based on the laser beam divergence angle and the near-field Rayleigh length, calculate the vertical spot radius expansion of the laser main lobe at the radial safety avoidance lower limit in the laser device; The vertical spot radius expansion is taken as a safety margin and added to the upper boundary thickness to obtain the vertical clearance height requirement. By inverting the trigonometric geometric relationship between the required vertical clearance height and the installation height of the laser device, the minimum pitch angle required for the laser main lobe to avoid the near-ground snow and fog layer is derived. Based on the angular resolution limitation of the servo mechanism in the laser device, the minimum pitch lift angle is rounded up to obtain the minimum pitch lift angle.

[0010] Preferably, the step of acquiring the cold radiation inversion gradient above the glacier surface during the horizontal reciprocating scan of the laser device includes: Before the laser device begins scanning, a vertically layered array of temperature sensors is installed above the glacier surface. During the horizontal reciprocating scan performed by the laser device, the air temperature sensor array is synchronously triggered to continuously sample the temperature and obtain the instantaneous air temperature value. Arrange the instantaneous air temperature values ​​at the same timestamp along the vertical direction to obtain the instantaneous temperature vertical profile above the glacier surface; The temperature difference between two adjacent height levels above the glacier surface is analyzed, and the ratio of the two temperature differences is calculated to obtain the vertical temperature gradient value. The vertical temperature gradient value is defined as the cold radiation inversion gradient.

[0011] Preferably, the step of predicting the vertical diffusion trend of the near-ground snow and fog layer based on the temperature inversion gradient, correcting the judgment criterion using the vertical diffusion trend, and simultaneously monitoring whether the near-ground snow and fog interference peak dissipates based on the second-corrected judgment criterion includes: The instantaneous value of the cold radiation inversion temperature gradient is used to identify the turbulent kinetic energy supply state in the vertical direction of the near-ground snow and fog layer; The turbulent kinetic energy supply state is divided into two types of turbulent development modes: buoyancy suppression-dominated and shear generation-awakening. Based on the two types of turbulence development modes, the relative strengths and weaknesses of the gravity settling flux and turbulent entrainment flux of snow crystal particles in the vertical direction in the near-ground snow fog layer are inferred. Based on the aforementioned win-loss relationship, predict the evolution trajectory of the upper boundary thickness of the near-ground snow fog layer; Determine the direction of evolution of the evolution trajectory, and modify the judgment criteria based on the vertical distribution change of particle concentration implied by the evolution direction; According to the revised judgment criteria, during the subsequent horizontal reciprocating scanning cycle, interference peaks are determined for each laser pulse to obtain the dissipation result of the near-ground snow fog interference peaks.

[0012] Preferably, when the near-ground snow and fog interference peak has not dissipated, raising the pitch angle of the laser device to the minimum pitch angle to obtain the actual pitch angle value includes: Read the dissipation result; if the result is that the dissipation has not occurred, generate a pitch angle lift trigger command. The minimum pitch angle is set as the target position command value of the pitch servo mechanism in the laser device; The pitch servo mechanism is driven with the target position command value as the driving target to obtain the actual pitch angle value.

[0013] Preferably, the step of acquiring data using the actual pitch angle value and spatially stitching the acquired point cloud data with the pitch angle before lifting to obtain a continuous point cloud includes: Based on the actual pitch angle value, the laser device is controlled to perform supplementary scanning on the spatial area within the scanning area that has not yet been acquired, to obtain the original point cloud data, and the initial point cloud data before lifting is recorded simultaneously. Using the optical center of the laser device as the origin and the horizontal plane as the reference plane, a local Cartesian coordinate system is constructed by combining the radial distance value, horizontal azimuth angle value and original pitch angle value of each laser foot point in the initial point cloud data, so as to obtain the local Cartesian point cloud set before lifting. The original point cloud data is transformed into Cartesian coordinates to obtain a local Cartesian point cloud set after lifting, and the overlapping parts in the merging result are removed to obtain a continuous point cloud.

[0014] A weather-modulated glacier surface laser scanning data acquisition system is used to implement a weather-modulated glacier surface laser scanning data acquisition method. The system includes: The determination module is used to emit laser pulses into the scanning area along the pitch angle direction of the laser device, and encapsulate the distance and intensity received when the laser pulses return into a parameter sequence, collect the snow albedo of the glacier surface in the scanning area at the current moment, and combine the snow albedo to determine the determination criteria for identifying near-ground snow fog interference peaks; The upper boundary analysis module is used to identify echo peaks belonging to the glacier surface by combining the parameter sequence, and to identify near-ground snow fog interference peaks located in front of the echo peaks and whose intensity values ​​exceed those of the echo peaks according to the judgment criteria. The radial distance corresponding to the near-ground snow fog interference peaks is determined as the upper boundary thickness of the near-ground snow fog layer in the scanning area. The elevation angle determination module is used to design the minimum pitch elevation angle that allows the main lobe of the laser device to avoid the near-ground snow and fog layer, based on the thickness of the upper boundary and the installation height of the laser device. The dissipation judgment module is used to collect the cold radiation inversion gradient above the glacier surface during the horizontal reciprocating scanning process of the laser device, predict the vertical diffusion trend of the near-ground snow fog layer based on the inversion gradient, correct the judgment criterion based on the vertical diffusion trend, and monitor whether the near-ground snow fog interference peak dissipates based on the second corrected judgment criterion. The actual pitch angle determination module is used to raise the pitch angle of the laser device to the minimum pitch lift angle when the near-ground snow fog interference peak has not dissipated, so as to obtain the actual pitch angle value. The continuous point cloud rendering module is used to complete the acquisition with the actual pitch angle value, and spatially stitch the acquired point cloud data with the pitch angle before lifting to obtain a continuous point cloud.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention constructs a near-ground snow and fog interference peak determination standard by jointly using snow albedo and laser echo characteristics. It can identify the thickness of the upper boundary of the near-ground snow and fog layer and calculate the minimum pitch rise angle for safe avoidance of the laser main lobe. It actively avoids Mie scattering interference from near-ground snow and fog from the source of acquisition, solving the problems of easy misjudgment in traditional fixed threshold echo discrimination and laser main lobe obstruction by snow and fog. It improves the accuracy of glacier surface echo signal recognition, avoids point cloud distortion, ranging jumps and missing effective data, and improves the integrity and reliability of glacier scanning raw data.

[0016] This invention achieves dynamic prediction and adaptive threshold correction of the vertical diffusion trend of near-ground snow and fog layers by introducing a cold radiation inverse temperature gradient. It can monitor the dissipation of interference peaks in real time and flexibly adjust the scanning attitude without relying on post-process data filtering, thus realizing weather-adaptive closed-loop control during the acquisition process. After completing the elevation angle lift to avoid interference, the point cloud data before and after the lift is fused through local Cartesian coordinate system transformation and spatial stitching algorithms to obtain continuous and complete glacier point cloud results. This ensures the continuity of long-term series observations and improves the efficiency and automation level of scanning operations, meeting the high-precision and robust ground laser scanning acquisition requirements under severe weather conditions in glacier areas. Attached Figure Description

[0017] Figure 1 A schematic flowchart of a weather-modulated glacier surface laser scanning data acquisition method provided in an embodiment of the present invention; Figure 2 A functional block diagram of a glacier ground laser scanning data acquisition system based on weather regulation provided in an embodiment of the present invention; The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0019] This application provides a method for acquiring glacier surface laser scanning data based on weather regulation. The executing entity of this method includes, but is not limited to, at least one of the following electronic devices that can be configured to execute the method provided in this application: a server, a terminal, etc. In other words, the method for acquiring glacier surface laser scanning data based on weather regulation can be executed by software or hardware installed on a terminal device or a server device. The server includes, but is not limited to, a single server, a server cluster, a cloud server, or a cloud server cluster. The server can be an independent server or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, content delivery networks, and big data and artificial intelligence platforms.

[0020] Reference Figure 1 The diagram shown is a schematic flowchart of a weather-modulated glacier surface laser scanning data acquisition method according to an embodiment of the present invention. In this embodiment, the weather-modulated glacier surface laser scanning data acquisition method includes: S1. A laser pulse is emitted into the scanning area along the pitch angle direction of the laser device, and the distance and intensity received when the laser pulse returns are encapsulated into a parameter sequence. The snow albedo of the glacier surface in the scanning area at the current moment is collected, and the judgment criteria for identifying near-ground snow fog interference peaks are determined in combination with the snow albedo.

[0021] In this embodiment, the step of collecting the snow albedo of the glacier surface in the scanned area at the current moment, and combining the snow albedo to determine the criteria for identifying near-ground snow fog interference peaks, includes: Using a pre-set portable spectroradiometer, select several snow sampling points within the scanning area, and sequentially collect the downward solar incident irradiance and upward snow reflected irradiance at each sampling point; The ratio of the downward solar incident irradiance to the upward snow reflected irradiance is taken as the spectral albedo of each sampling point; Calculate the average value of the spectral albedo to obtain the snow albedo of the scanned area; By combining the operating wavelength of the laser device with the snow albedo, the theoretical echo intensity benchmark of the laser pulse on the glacier surface under the current snow cover condition is calculated. Using the theoretical echo intensity benchmark, the criteria for determining near-ground snow and fog interference peaks are established.

[0022] Specifically, the pitch angle refers to the elevation angle of the laser device in the vertical plane relative to the horizontal reference plane. It is used to control the upward or downward emission direction of the laser pulse to avoid the near-ground snow and fog layer.

[0023] A laser pulse is a short-duration, high-intensity beam of light emitted by a laser device in a glacial environment. It serves as a detection signal, and the distance to the target is obtained by measuring its round-trip flight time.

[0024] The scanning area is a specific spatial range on the glacier surface selected for three-dimensional laser scanning, often covering areas with snow cover and potential near-ground snow fog.

[0025] Distance is the radial straight-line length corresponding to the laser pulse reaching the target surface and being reflected back after being emitted from the laser device, directly reflecting the spatial positional relationship between the target and the scanner.

[0026] Intensity is the amplitude value of the echo signal obtained after the return laser pulse is converted by photoelectric conversion, which characterizes the strength of the reflected energy of the laser by the glacier surface or snow and fog particles.

[0027] The parameter sequence is a data set formed by sequentially encapsulating the radial distance and echo intensity obtained from the same laser pulse.

[0028] Snow albedo is the ability of snow on the surface of a glacier to reflect solar radiation back into the sky. It is affected by snow crystal size, water content, and aging degree. Combined with laser wavelength, it can be used to assess the inherent reflectivity of the snow surface to laser.

[0029] Near-ground snow fog interference peaks are false intensity peaks that appear in front of the true echo peaks on the glacier surface in the parameter sequence. They are caused by strong scattering of laser light by snow crystal particles suspended in the near-ground snow fog layer and are a typical waveform feature for determining snow fog interference.

[0030] The judgment criteria are intensity thresholds or criteria set based on the theoretical echo intensity baseline value calculated from the snow albedo. They are used to clearly identify near-ground snow fog interference peaks from the parameter sequence and distinguish them from normal glacier surface echoes.

[0031] A portable spectroradiometer is an optical measuring instrument that can be operated by hand in the field. It can measure downlink and uplink spectral irradiance separately, thereby obtaining the spectral reflectance characteristics of snow at multiple wavelengths.

[0032] Snow sampling points are representative snow surface locations manually selected within the scanning area for on-site measurement of the optical properties of snow.

[0033] Downward solar incident irradiance is the irradiance energy of solar radiation reaching the surface of the snow sampling point in the form of a spectrum, and is directly affected by the solar altitude angle and weather conditions.

[0034] Upward snow reflectance is a measure of the spectral irradiance of the snow surface after reflecting downward solar radiation to the upper hemisphere, reflecting the level of energy reflection of the snow surface at various wavelengths.

[0035] Spectral albedo is the ratio obtained by dividing the upward snow reflectance irradiance by the downward solar incident irradiance at the same sampling point wavelength by wavelength, representing the snow's reflectivity to different wavelengths of light at that point.

[0036] The operating wavelength of a laser device is the center wavelength of the laser source.

[0037] The theoretical echo intensity benchmark is the expected echo intensity level of the glacier surface to the laser pulse, calculated based on the working wavelength of the laser device and the measured snow albedo.

[0038] In detail, at the glacier site, the laser device emits laser pulses toward the selected scanning area according to the initial pitch angle. The laser emitter and photodetector inside the device work together to sample the returned laser pulses at high speed and obtain the radial distance using a time-series discrimination method. The amplitude of the echo voltage is captured by analog-to-digital conversion to obtain the intensity, and the distance and intensity of the same measurement point are encapsulated into a parameter sequence by the synchronous control unit.

[0039] First, point the optical probe of the radiometer vertically toward the sky and collect the descending solar irradiance projected onto the snow surface at this moment. Then, the same probe was vertically aligned with the snow surface to collect the upward snow reflectance irradiance reflected from the snow surface. The two sets of irradiance data for each sampling point were recorded and stored in sequence.

[0040] The data acquisition unit automatically calculates the ratio of downlink to uplink irradiance at each point using its built-in computing function, obtaining the spectral albedo of that sampling point. Then, it calculates the arithmetic mean of the spectral albedo of all sampling points to obtain the snow albedo representing the current state of the glacier.

[0041] Next, based on the fixed operating wavelength of the laser device and the snow albedo, the theoretical echo intensity benchmark that the glacier surface should have for the laser pulse under this snow condition was derived.

[0042] Finally, using this theoretical echo intensity benchmark as the core reference, an appropriate intensity recognition threshold is artificially set as the criterion for identifying near-ground snow and fog interference peaks.

[0043] S2. Based on the parameter sequence, identify the echo peaks belonging to the glacier surface. According to the judgment criteria, identify the near-ground snow fog interference peaks that are in front of the echo peaks and whose intensity values ​​exceed the echo peaks. Determine the radial distance corresponding to the near-ground snow fog interference peaks as the upper boundary thickness of the near-ground snow fog layer in the scanning area.

[0044] In this embodiment, the step of identifying echo peaks belonging to the glacier surface by combining the parameter sequence, and identifying near-ground snow fog interference peaks located in front of the echo peaks and with intensity values ​​exceeding the echo peaks according to the judgment criteria, includes: The parameter sequence received by the laser device is acquired, and the discrete sequences of distance and intensity are extracted from the parameter sequence; Correct and remove the background noise in the discrete sequence to obtain the net echo intensity sequence; Retrieve echo peaks that match the corresponding morphological characteristics of the glacier surface from the net echo intensity sequence, and determine the peak value of the echo peaks; Using the radial distance of the echo peak as the dividing boundary, the front end interval of the net echo intensity sequence is taken as the search range of near-ground snow and fog interference peaks; Based on the aforementioned criteria, near-ground snow and fog interference peaks are identified from the search range.

[0045] Specifically, a discrete sequence is a one-dimensional data queue formed by arranging the distance and intensity values ​​corresponding to each laser beam in the parameter sequence according to the order in which the lasers are emitted.

[0046] The noise floor is the basic signal level composed of dark current, thermal noise, and shot noise that still exists in the photodetector and preamplifier circuit of the laser device when there is no target echo input. It will appear as a continuous low-amplitude random fluctuation in the discrete sequence.

[0047] The net echo intensity sequence is the effective echo intensity sequence that is retained only when the laser pulse irradiates the actual scattering target after subtracting the mean of the background noise and removing abnormal jump points from the discrete sequence.

[0048] The morphological characteristics of the glacier surface are determined by the roughness, surface density, and texture direction of the glacier ice body or snow layer. The undulation and broadening patterns of the reflected laser echo waveform reflect the unique echo shape of the glacier surface, which is different from targets such as snow fog and rocks.

[0049] The echo peak is the waveform structure of the maximum intensity generated by the laser reflected from the glacier surface in the net echo intensity sequence, and the radial distance of the peak is the location of the glacier surface.

[0050] The peak value is the intensity value of the sampling point where the intensity value reaches its maximum within the range of the echo peak shape. It represents the strongest feedback position of the laser energy reflected from the glacier surface and is used to accurately locate the distance to the ground.

[0051] Radial distance specifically refers to the straight-line distance from the laser device to the glacier surface at the peak of the echo, serving as a geographical reference baseline for defining the near-ground interference detection range.

[0052] The separation boundary is based on the radial distance value corresponding to the echo peak on the glacier surface. The net echo intensity sequence is divided into a front-end region closer to the glacier surface and a back-end region farther away along the distance axis, so that the retrieval of snow fog interference is limited to the front-end region.

[0053] The front-end interval is a distance range in the net echo intensity sequence from the nearest receiving point to the radial distance before the peak value of the echo on the glacier surface. All high-intensity echo signals within this interval may originate from suspended particles in the near-ground snow fog layer along the laser path.

[0054] Near-ground snow fog interference peaks are isolated peaks that appear within the search range, with intensity values ​​exceeding the intensity of glacier surface echo peaks, steep waveforms, and obvious pulse-like patterns. They are caused by strong Mie scattering of laser pulses by fine snow crystal particles suspended above the glacier surface.

[0055] In detail, the laser device reads the parameter sequence corresponding to each laser pulse obtained from the buffer completely, and extracts the distance and intensity contained therein one by one according to the acquisition sequence number, forming a distance-intensity discrete sequence arranged along the distance variation; By statistically analyzing the background signal collected by the laser device when there is no laser emission, the average level of the background noise is obtained. Then, the background noise level is subtracted point by point from each intensity value in the discrete sequence. At the same time, obvious abnormal abrupt changes caused by circuit jitter and other reasons are eliminated to obtain the net echo intensity sequence that retains only the target scattered echo information. In the net echo intensity sequence, the echo amplitude is compared point by point along the direction of increasing distance to find waveform segments that match the unique morphological characteristics of the glacier surface, such as backscattering broadening and gradual change of the descent edge, and to locate the echo peaks belonging to the glacier surface. The amplitude of the sampling point with the highest intensity within the echo peak is taken as its peak value. At the same time, the radial distance corresponding to the peak value is recorded and marked as the dividing boundary. All sampling points in the net echo intensity sequence that are located before this boundary are defined as the front search range of the near-ground snow and fog interference peak.

[0056] Within this search range, if the intensity value of a certain sampling point exceeds the intensity value of the echo peak on the glacier surface and its waveform features an independent peak shape, then the echo structure corresponding to that sampling point is identified as a near-ground snow fog interference peak.

[0057] In this embodiment, determining the radial distance corresponding to the near-ground snow fog interference peak as the upper boundary thickness of the near-ground snow fog layer in the scanning area includes: Verify the waveform characteristics of the near-ground snow and fog interference peak in the net echo intensity sequence; Based on the waveform characteristics, it was confirmed that the near-ground snow fog interference peak originated from Mie scattering of suspended snow crystal particles within the near-ground snow fog layer, rather than from other non-target scattering sources. Based on the current pitch angle of the laser device, the radial distance is decomposed by slant range projection in the vertical direction to obtain the vertical elevation component of the interference peak relative to the horizontal plane where the laser device is located. The vertical elevation component is defined as the upper boundary thickness of the near-ground snow and fog layer.

[0058] Specifically, waveform characteristics are the amplitude fluctuations of a certain echo structure in the net echo intensity sequence on the distance axis, including visible visual waveform attributes such as the steepness of the peak rise, the sharpness of the peak top, the decay rate of the falling edge, and the symmetry of the two sides of the peak.

[0059] The near-ground snow fog layer is an air layer rich in tiny suspended snow crystal particles that lies above the glacier surface and close to the ground.

[0060] Suspended snow crystal particles are ice crystal particles floating in the near-ground snow fog layer. Their particle size is close to or larger than the working wavelength of the laser device. They are formed by being carried by airflow in a frozen environment and at low temperatures.

[0061] Mie scattering is a light scattering process that occurs when the laser wavelength is similar to the size of the scattering particles. Suspended snow crystal particles produce strong anisotropic forward and backward scattering of laser pulses, resulting in high echo intensity and concentrated waveforms, which are significantly different in shape from Rayleigh scattering produced by atmospheric molecules.

[0062] Non-target scattering sources are scatterers that can generate echo signals in glacier scanning other than suspended snow crystal particles, such as background atmospheric aerosols, extremely fine ice crystal fog, locally stirred-up dust, or electromagnetic interference jumps.

[0063] The pitch angle is the angle between the optical axis of a laser device and the horizontal plane when the device performs a scan instantaneously.

[0064] Slant range projection decomposition is the process of breaking down the slant range, expressed as radial distance, into two parts along the vertical and horizontal directions according to trigonometric relationships. The pitch angle determines the proportion of the vertical component during decomposition.

[0065] The vertical elevation component is the distance value along the vertical direction obtained after the slant range projection decomposition, representing the scale of the scattering position corresponding to the near-ground snow fog interference peak in the vertical direction above the horizontal plane where the laser device is located.

[0066] The horizontal plane is an imaginary horizontal reference plane constructed with the optical center of the laser device as the reference point.

[0067] The upper boundary thickness is the vertical height measured from the horizontal plane where the laser device is located to the upper edge of the area where the scattering particles are concentrated at the top of the near-ground snow fog layer, representing the main thickness of the snow fog layer in the vertical direction.

[0068] In detail, the point-by-point intensity value corresponding to the interference peak is extracted from the net echo intensity sequence, and the steepness of its intensity rise and fall, the sharpness of the peak, and the presence of multiple fluctuations are carefully observed along the distance axis to verify the waveform characteristics of the interference peak. The waveform characteristics obtained from the verification were then compared with the known scattering patterns of suspended snow crystal particles, with a focus on whether they exhibited a typical Mie scattering waveform pattern with a steep leading edge, a narrow peak, a rapidly decaying trailing edge, and no obvious tail. Based on this, it was confirmed that the interference peak originated from Mie scattering of suspended snow crystal particles in the near-ground snow fog layer, rather than interference caused by atmospheric molecule scattering, electronic disturbances, or distant non-target scattering sources. The pitch angle value of the current execution fed back by the laser device servo system was read, and this angle was used as the geometric parameter for slant range projection decomposition. The radial distance corresponding to the interference peak was projected along the measurement slant side into the vertical direction, separating two orthogonal components, namely vertical and horizontal, thereby obtaining the vertical elevation component of the interference peak scattering position relative to the horizontal plane where the laser device is located.

[0069] S3. Based on the thickness of the upper boundary and the installation height of the laser device, design the minimum pitch angle that allows the main lobe of the laser device to avoid the near-ground snow and fog layer.

[0070] In this embodiment, designing the minimum pitch angle that allows the main lobe of the laser device to avoid the near-ground snow and fog layer, based on the thickness of the upper boundary and the installation height of the laser device, includes: The upper boundary thickness is converted into a radial safety avoidance lower limit along the scanning direction of the laser device; The laser beam divergence angle and near-field Rayleigh length are introduced from the factory-issued optical parameters of the laser device. Based on the laser beam divergence angle and the near-field Rayleigh length, calculate the vertical spot radius expansion of the laser main lobe at the radial safety avoidance lower limit in the laser device; The vertical spot radius expansion is taken as a safety margin and added to the upper boundary thickness to obtain the vertical clearance height requirement. By inverting the trigonometric geometric relationship between the required vertical clearance height and the installation height of the laser device, the minimum pitch angle required for the laser main lobe to avoid the near-ground snow and fog layer is derived. Based on the angular resolution limitation of the servo mechanism in the laser device, the minimum pitch lift angle is rounded up to obtain the minimum pitch lift angle.

[0071] Specifically, the radial safety avoidance lower limit is the shortest radial slant distance required to ensure that the lower edge of the laser main lobe can completely pass over the near-ground snow and fog layer along the line of sight of the laser device scanning direction. It is obtained by projecting the vertical upper boundary thickness through the scanning direction.

[0072] The laser beam divergence angle is the half-angle of the beam cross-section radius that increases with distance when the laser beam emitted by the laser device propagates in the far field.

[0073] The near-field Rayleigh length is the axial distance from the laser device's output port along the optical axis to where the beam cross-section radius extends to √2 times the beam waist radius.

[0074] The laser main lobe is the central main lobe where the energy of the laser beam emitted by the laser device is most concentrated on a spatial cross-section.

[0075] The vertical spot radius expansion is the increase in the spot radius of the laser main lobe in the vertical direction compared to the beam waist, due to the laser beam divergence characteristics at the radial safety avoidance lower limit slant distance.

[0076] The safety margin is the amount of vertical beam radius expansion converted into additional vertical avoidance space, which is used to ensure that even the edge of the laser main lobe does not intrude into the near-ground snow and fog layer, and to avoid the lower half of the beam from partially irradiating snow and fog particles and causing interference.

[0077] The vertical clearance height requirement is the minimum absolute height that the lower edge of the laser main lobe must reach in the vertical direction after adding the upper boundary thickness and the vertical spot radius expansion as a safety margin.

[0078] The installation height of the laser device is the vertical height of its optical center relative to the glacier surface.

[0079] The triangular geometric relationship is the geometric relationship between angles and side lengths in a right triangle formed by the optical center of the laser device as the vertex, the installation height and vertical clearance height requirements as the vertical sides, and the horizontal component of the radial safety avoidance lower limit projection as the base.

[0080] The minimum pitch lift angle is the minimum angle at which the optical axis of the laser device needs to be lifted upward from its current direction when scanning is completed in non-interference mode and the main lobe of the laser is just above the critical position of the near-ground snow and fog layer.

[0081] The angular resolution limit of the servo mechanism is the minimum angular increment that the pitch servo system in a laser device can execute.

[0082] In detail, by utilizing the geometric angle relationship between the current scanning direction of the laser device and the vertical direction, the calculated upper boundary thickness is triangularly projected along the line of sight and converted into a radial safety avoidance lower limit to obtain the corresponding slant distance value. Subsequently, the factory optical parameter document accompanying the laser device was consulted. Based on the optical characteristic that the laser beam will propagate in a straight line with the divergence angle as the expansion angle after exceeding the Rayleigh length, the relative relationship between the slant distance given by the lower limit of radial safety avoidance and the near-field Rayleigh length was determined. The increase in the beam cross-sectional radius in the vertical direction was calculated from the laser beam divergence angle, thereby obtaining the vertical beam radius expansion. The vertical beam radius expansion is directly regarded as a safety margin to ensure that the lower edge of the main lobe does not touch the snow and fog. It is then added to the upper boundary thickness to obtain the vertical clearance height requirement. Taking the optical center of the laser device as the vertex, the installation height is used as a right-angled side. The vertical difference between the vertical clearance height requirement and the installation height is used as the relative elevation. The projection distance of the radial safety avoidance lower limit in the horizontal plane is used to form the base. The corresponding elevation angle in the right triangle is inverted through trigonometric relationships to derive the minimum pitch angle that theoretically allows the laser main lobe to just pass over the snow and fog layer. Finally, the technical specifications of the pitch servo mechanism in the laser device are read to obtain its inherent angular resolution limit value. The derived minimum pitch lift angle is rounded up to the nearest integer multiple of this angular resolution value, thereby generating the minimum pitch lift angle that the laser device can actually execute and ensure safety.

[0083] In this embodiment, the formula for calculating the minimum pitch lift angle is: in: For the minimum pitch angle, The thickness is the upper boundary. The laser operating wavelength, For transmission quality function, The Mie scattering asymmetry factor. The initial scan pitch angle, For near-field Rayleigh length, For the angular resolution of the servo mechanism, The installation height of the laser device, The rounding up symbol.

[0084] Specifically, ; Furthermore, It is the characteristic length of a Gaussian beam, defined as the propagation distance required for the beam area to double from the beam waist; is the Mie scattering asymmetry factor, a physical quantity that describes the directional preference of suspended snow crystal particles in the near-ground snow fog layer for laser scattering. Its value ranges from [-1, 1]. When g approaches 1, it means that almost all the scattered light is concentrated in the forward direction, the energy penetration is strong, and the contamination area of ​​the laser main lobe by the snow crystal is relatively compact. When g approaches 0, it indicates that the scattering is approximately isotropic, the scattered energy is uniformly distributed in space, and the interference region diffuses in a spherical shape. When g approaches -1, it means that almost all the scattered light is reflected back, forming a strong backscattered echo, and the interference area is elongated in the direction of the beam.

[0085] It maps the scattering directionality preference to an amplification factor for the effective interference radius of snow and fog. When scattering approaches isotropic or backscattering is dominant, this factor increases, and the safety margin is automatically increased; when forward scattering is dominant, the factor tends to decrease.

[0086] More specifically, this formula incorporates the scattering directionality of particles within the snow fog layer into the avoidance criterion through the Mie scattering asymmetry factor. This means that snow fog is not a hard boundary with a fixed thickness, and its effective interference radius will dynamically change with the shape and size distribution of snow crystals, making the model more consistent with real physical processes.

[0087] Nonlinear transmission quality function The ratio of Rayleigh length to detection distance is nonlinearly compressed using a morphological function containing an arctangent function to simulate the equivalent diffusion saturation effect when a beam propagates in a medium.

[0088] S4. During the horizontal reciprocating scanning process of the laser device, the cold radiation inversion gradient above the glacier surface is collected. The vertical diffusion trend of the near-ground snow fog layer is predicted based on the inversion gradient. The judgment criterion is corrected based on the vertical diffusion trend. At the same time, the near-ground snow fog interference peak is monitored for dissipation based on the second corrected judgment criterion.

[0089] In this embodiment, the step of acquiring the cold radiation inversion gradient above the glacier surface during the horizontal reciprocating scan of the laser device includes: Before the laser device begins scanning, a vertically layered array of temperature sensors is installed above the glacier surface. During the horizontal reciprocating scan performed by the laser device, the air temperature sensor array is synchronously triggered to continuously sample the temperature and obtain the instantaneous air temperature value. Arrange the instantaneous air temperature values ​​at the same timestamp along the vertical direction to obtain the instantaneous temperature vertical profile above the glacier surface; The temperature difference between two adjacent height levels above the glacier surface is analyzed, and the ratio of the two temperature differences is calculated to obtain the vertical temperature gradient value. The vertical temperature gradient value is defined as the cold radiation inversion gradient.

[0090] Specifically, the instantaneous air temperature value is the real-time air temperature reading measured and output by a single air temperature sensor at a specific sampling moment during continuous temperature sampling.

[0091] The instantaneous temperature vertical profile is a one-dimensional height-temperature correspondence sequence formed by arranging the instantaneous air temperature values ​​collected at all altitude levels at the same time stamp in ascending order of altitude.

[0092] The temperature difference is the difference between the instantaneous air temperature measured at a higher altitude level and the instantaneous air temperature measured at the immediately following lower altitude level at the same time stamp.

[0093] The vertical temperature gradient value is the temperature change per unit height obtained by calculating the ratio of the temperature difference between two adjacent height levels to the height interval they span.

[0094] The cold radiation inversion temperature gradient is the vertical temperature gradient value measured when the temperature in the near-surface air layer increases with altitude due to the strong long-wave radiation cooling of the glacier surface in a glacial environment. A positive gradient means that the near-surface is colder and the upper part is warmer, forming a temperature inversion state, which becomes a stable stratification that inhibits the vertical diffusion of snow and fog.

[0095] In detail, multiple temperature sensors are fixedly installed on a vertical support at predetermined height intervals, and the probes of each sensor are adjusted to face the open air. Then, the laser device is started to perform horizontal reciprocating scanning, and a unified trigger pulse signal is issued by the synchronous controller to drive all sensors in the temperature sensor array to start continuous temperature sampling at a consistent sampling frequency. After each sampling, the temperature values ​​of all height levels at the same moment are extracted and arranged in order of sensor installation height from low to high to form the instantaneous temperature vertical profile above the glacier surface at that moment. In the instantaneous temperature vertical profile, two adjacent height levels are selected one by one from top to bottom or bottom to top, and the temperature difference between the instantaneous air temperature values ​​of the two levels is calculated. Then, the temperature difference obtained from each pair of adjacent levels is converted into a ratio with the known installation height distance between the two levels to obtain the vertical temperature gradient value corresponding to each height segment.

[0096] In this embodiment, the step of predicting the vertical diffusion trend of the near-ground snow fog layer based on the temperature inversion gradient, correcting the judgment criterion using the vertical diffusion trend, and simultaneously monitoring whether the near-ground snow fog interference peak dissipates based on the second-corrected judgment criterion includes: The instantaneous value of the cold radiation inversion temperature gradient is used to identify the turbulent kinetic energy supply state in the vertical direction of the near-ground snow and fog layer; The turbulent kinetic energy supply state is divided into two types of turbulent development modes: buoyancy suppression-dominated and shear generation-awakening. Based on the two types of turbulence development modes, the relative strengths and weaknesses of the gravity settling flux and turbulent entrainment flux of snow crystal particles in the vertical direction in the near-ground snow fog layer are inferred. Based on the aforementioned win-loss relationship, predict the evolution trajectory of the upper boundary thickness of the near-ground snow fog layer; Determine the direction of evolution of the evolution trajectory, and modify the judgment criteria based on the vertical distribution change of particle concentration implied by the evolution direction; According to the revised judgment criteria, during the subsequent horizontal reciprocating scanning cycle, interference peaks are determined for each laser pulse to obtain the dissipation result of the near-ground snow fog interference peaks.

[0097] Specifically, the turbulent kinetic energy supply state is the energy source situation that maintains or generates turbulent motion within the near-ground snow and fog layer. It is determined by the relative strength of the instantaneous value of the cold radiation inversion temperature gradient doing work on buoyancy in the vertical direction or the wind speed shear doing work on turbulence, which determines whether turbulence can develop and be maintained.

[0098] The buoyancy suppression-dominated mode is a turbulence development mode in which the density stratification in the near-surface air layer is extremely stable when the cold radiation inverse temperature gradient is strong. The air parcels are subjected to buoyancy recovery in the vertical direction opposite to the displacement direction, which leads to the buoyancy kinetic energy being consumed by turbulence and the turbulence development being suppressed.

[0099] The shear-generated awakening mode is a turbulence development mode in which wind shear converts average kinetic energy into turbulent kinetic energy when there is a sufficient difference in wind speed in the vertical direction above the glacier surface. Even with some temperature inversion suppression, it can overcome buoyancy dissipation and regenerate turbulence.

[0100] Snow crystal microparticles are tiny ice crystal particles suspended in the near-ground snow and fog layer.

[0101] Gravity settling flux is the net downward migration of snow crystal particles to the ice surface under their own weight when there is no turbulence or weak turbulence.

[0102] Turbulent entrainment flux is the net upward transport of high-concentration snow crystal particles from the lower layer, which are carried upward by turbulent eddy activity of sufficient intensity in the near-ground snow and fog layer and mixed with low-concentration air in the upper layer.

[0103] The win-loss relationship is a comparison of the magnitudes of gravity settling flux and turbulent entrainment flux in the vertical direction.

[0104] The evolution trajectory is the continuous change path of the upper boundary thickness over time, and the evolution direction is the direction in which the evolution trajectory extends along the time axis.

[0105] The vertical distribution change of particle concentration is a redistribution of the number density distribution of snow crystal particles at various height layers in the vertical direction as the upper boundary thickness evolves.

[0106] The judgment criteria are intensity identification thresholds and waveform criteria set based on the current snow cover and snow fog conditions, used to identify near-ground snow fog interference peaks from the net echo intensity sequence.

[0107] In detail, using the instantaneous value of the cold radiation inversion gradient that has just been obtained, we can determine whether the value is positive and its magnitude. If the positive value is strong, the buoyancy suppression effect in the vertical direction is significant, and the turbulent kinetic energy supply state is dominated by buoyancy suppression, making it difficult for turbulence to develop. If the instantaneous value is significantly weakened or even close to zero, and we combine this with the presence or absence of vertical wind shear above the glacier surface, if there is strong wind shear, the state can be classified as shear generation awakening type, indicating that the turbulence is being reawakened.

[0108] Based on one of the two turbulence development modes, the relative strengths of gravity settling flux and turbulent entrainment flux are compared: under the buoyancy suppression-dominated mode, turbulent entrainment flux is severely weakened, gravity settling flux prevails, and snow crystals will gradually settle towards the glacier surface; under the shear generation-awakening mode, turbulent entrainment flux gradually increases and exceeds gravity settling flux, and snow crystals are carried upward and diffused.

[0109] Based on the above-mentioned win-lose relationship, the evolution trajectory of the upper boundary thickness in the short term can be inferred. If subsidence is dominant, the trajectory will show a downward thinning, while if entrainment is dominant, the trajectory will show an upward thickening.

[0110] Observe the direction of the evolution trajectory and infer how the vertical distribution of particle concentration will change. For example, a thinning of the upper boundary thickness means a decrease in the concentration of particles in the upper layers. Based on this, the intensity threshold in the judgment criteria should be corrected in the direction of decrease, or the expected scattering intensity in the waveform criterion should be recalibrated.

[0111] Then, after the laser device enters the next horizontal reciprocating scanning cycle, the corrected judgment criteria are loaded into the interference discrimination stage. The front end interval of the net echo intensity sequence corresponding to each laser pulse is judged one by one to detect whether there are still isolated spikes that exceed the correction threshold and whose waveform characteristics conform to Mie scattering.

[0112] Finally, based on the continuous discrimination results of each pulse, a comprehensive judgment is made as to whether the entire near-ground snow and fog interference peak still exists or has dissipated during the scanning period.

[0113] S5. When the near-ground snow fog interference peak has not dissipated, raise the pitch angle of the laser device to the minimum pitch angle to obtain the actual pitch angle value.

[0114] In this embodiment, the step of raising the pitch angle of the laser device to the minimum pitch angle to obtain the actual pitch angle value when the near-ground snow fog interference peak has not dissipated includes: Read the dissipation result; if the result is that the dissipation has not occurred, generate a pitch angle lift trigger command. The minimum pitch angle is set as the target position command value of the pitch servo mechanism in the laser device; The pitch servo mechanism is driven with the target position command value as the driving target to obtain the actual pitch angle value.

[0115] Specifically, the pitch angle rise trigger command is an electrical control command generated by the control decision unit of the laser device when the dissipation result clearly indicates that the laser has not dissipated.

[0116] The target position command value is a specific angle value written into the pitch servo mechanism controller.

[0117] The actual pitch angle value is the pitch angle that the optical axis of the laser device actually reaches in the vertical plane, which is ultimately adjusted by the pitch servo mechanism through motor motion and position sensor feedback.

[0118] In detail, the control software of the laser device converts the minimum pitch angle into a digital quantity that matches the resolution of the pitch servo mechanism encoder, and then writes the digital quantity into the target position register of the servo driver via the data bus. The servo drive performs closed-loop position control centered on the set target position command value. Its internal position loop adjusts the drive current and direction of the motor in real time according to the difference between the target value and the actual angle fed back by the current encoder. The drive motor drives the optical stage of the laser device to rotate around the horizontal axis through the reducer.

[0119] S6. Complete the acquisition using the actual pitch angle value, and spatially stitch the acquired point cloud data with the pitch angle before lifting to obtain a continuous point cloud.

[0120] In this embodiment, the step of acquiring data using the actual pitch angle value and spatially stitching the acquired point cloud data with the pitch angle before lifting to obtain a continuous point cloud includes: Based on the actual pitch angle value, the laser device is controlled to perform supplementary scanning on the spatial area within the scanning area that has not yet been acquired, to obtain the original point cloud data, and the initial point cloud data before lifting is recorded simultaneously. Using the optical center of the laser device as the origin and the horizontal plane as the reference plane, a local Cartesian coordinate system is constructed by combining the radial distance value, horizontal azimuth angle value and original pitch angle value of each laser foot point in the initial point cloud data, so as to obtain the local Cartesian point cloud set before lifting. The original point cloud data is transformed into Cartesian coordinates to obtain a local Cartesian point cloud set after lifting, and the overlapping parts in the merging result are removed to obtain a continuous point cloud.

[0121] Specifically, raw point cloud data is information obtained without stitching after performing supplementary scanning on spatial areas that have not yet been fully collected using actual pitch angle values.

[0122] The initial point cloud data before the lift is the glacier surface point cloud data that has been scanned and recorded using the original pitch angle before the laser device's pitch angle is lifted.

[0123] The horizontal plane is a horizontal reference plane determined by leveling the device using the optical center of the laser device and the built-in tilt sensor.

[0124] Laser footprints are discrete measurement points formed when a laser pulse is irradiated onto the surface of a glacier or a near-ground snow and fog layer.

[0125] The radial distance value is the slant distance from the optical center of the laser device to the laser foot point.

[0126] The horizontal azimuth angle is the angle of deflection of the laser foot point in the horizontal plane relative to the reference direction line of the laser device.

[0127] The original pitch angle value is the pitch angle used by the laser device when performing the initial scan before lifting.

[0128] The local Cartesian coordinate system is a right-handed three-dimensional rectangular coordinate system with the optical center of the laser device as the origin, the horizontal plane as the reference plane, the front of the device as a certain horizontal axis, and the vertical upward as the elevation axis. It is used to convert polar coordinate observations into a unified rectangular coordinate representation.

[0129] Cartesian coordinate transformation is the process of calculating the X, Y, and Z component coordinates of each laser footpoint in the original point cloud data in the local Cartesian coordinate system using the actual pitch angle, horizontal azimuth angle, and radial distance values ​​through trigonometric projection.

[0130] The overlapping portion in the merged result is the spatially overlapping area where the local Cartesian point cloud before and after the lift is located.

[0131] like Figure 2 The diagram shown is a functional block diagram of a glacier ground laser scanning data acquisition system based on weather regulation, provided in an embodiment of the present invention.

[0132] The weather-adjustable glacier surface laser scanning data acquisition system 100 described in this invention can be installed in an electronic device. Depending on the functions implemented, the weather-adjustable glacier surface laser scanning data acquisition system 100 may include a determination module 101, an upper boundary analysis module 102, a lift angle determination module 103, a dissipation determination module 104, an actual pitch angle determination module 105, and a continuous point cloud rendering module 106. The module described in this invention can also be called a unit, referring to a series of computer program segments that can be executed by the processor of an electronic device and perform a fixed function, stored in the memory of the electronic device.

[0133] In this embodiment, the functions of each module / unit are as follows: The determination module 101 is used to emit laser pulses into the scanning area along the pitch angle direction of the laser device, encapsulate the distance and intensity received when the laser pulse returns into a parameter sequence, collect the snow albedo of the glacier surface in the scanning area at the current moment, and determine the determination criteria for identifying near-ground snow fog interference peaks by combining the snow albedo. Upper boundary analysis module 102 is used to identify echo peaks belonging to the glacier surface by combining the parameter sequence, and to identify near-ground snow fog interference peaks located in front of the echo peaks and whose intensity values ​​exceed the echo peaks according to the judgment criteria. The radial distance corresponding to the near-ground snow fog interference peaks is determined as the upper boundary thickness of the near-ground snow fog layer in the scanning area. The elevation angle determination module 103 is used to design the minimum pitch elevation angle that enables the main lobe of the laser device to avoid the near-ground snow and fog layer based on the thickness of the upper boundary and the installation height of the laser device. The dissipation judgment module 104 is used to collect the cold radiation inversion gradient above the glacier surface during the horizontal reciprocating scanning process of the laser device, predict the vertical diffusion trend of the near-ground snow fog layer based on the inversion gradient, correct the judgment criterion based on the vertical diffusion trend, and monitor whether the near-ground snow fog interference peak dissipates based on the second corrected judgment criterion. The actual pitch angle determination module 105 is used to raise the pitch angle of the laser device to the minimum pitch lift angle when the near-ground snow fog interference peak has not dissipated, so as to obtain the actual pitch angle value. The continuous point cloud drawing module 106 is used to complete the acquisition with the actual pitch angle value, and to spatially stitch the acquired point cloud data with the pitch angle before lifting to obtain a continuous point cloud.

[0134] In the several embodiments provided by this invention, it should be understood that the disclosed methods and systems can be implemented in other ways. For example, the system embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and other division methods may be used in actual implementation.

[0135] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0136] Furthermore, the functional modules in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in the form of hardware plus software functional modules.

[0137] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0138] The embodiments of this application can acquire and process relevant data based on artificial intelligence technology. Artificial intelligence is the theory, method, technology, and application system that uses digital computers or machines controlled by digital computers to simulate, extend, and expand human intelligence, perceive the environment, acquire knowledge, and use that knowledge to obtain optimal results.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for acquiring glacier surface laser scanning data based on weather regulation, characterized in that, The method includes: S1. Along the pitch angle direction of the laser device, a laser pulse is emitted into the scanning area, and the distance and intensity received when the laser pulse returns are encapsulated into a parameter sequence. The snow albedo of the glacier surface in the scanning area at the current moment is collected, and the judgment criteria for identifying near-ground snow fog interference peaks are determined in combination with the snow albedo. S2. Based on the parameter sequence, identify the echo peaks belonging to the glacier surface. According to the judgment criteria, identify the near-ground snow fog interference peaks that are in front of the echo peaks and whose intensity values ​​exceed the echo peaks. Determine the radial distance corresponding to the near-ground snow fog interference peaks as the upper boundary thickness of the near-ground snow fog layer in the scanning area. S3. Based on the thickness of the upper boundary and the installation height of the laser device, design the minimum pitch angle that allows the main lobe of the laser device to avoid the near-ground snow and fog layer; S4. During the horizontal reciprocating scanning process of the laser device, the cold radiation inversion gradient above the glacier surface is collected. The vertical diffusion trend of the near-ground snow fog layer is predicted based on the inversion gradient. The judgment criterion is corrected based on the vertical diffusion trend. At the same time, the near-ground snow fog interference peak is monitored for dissipation based on the second corrected judgment criterion. S5. When the near-ground snow fog interference peak has not dissipated, raise the pitch angle of the laser device to the minimum pitch angle to obtain the actual pitch angle value; S6. Complete the acquisition using the actual pitch angle value, and spatially stitch the acquired point cloud data with the pitch angle before lifting to obtain a continuous point cloud.

2. The method for acquiring glacier surface laser scanning data based on weather regulation as described in claim 1, characterized in that, The process involves collecting the snow albedo of the glacier surface in the scanned area at the current moment, and combining this snow albedo to determine the criteria for identifying near-ground snow fog interference peaks, including: Using a pre-set portable spectroradiometer, select several snow sampling points within the scanning area, and sequentially collect the downward solar incident irradiance and upward snow reflected irradiance at each sampling point; The ratio of the downward solar incident irradiance to the upward snow reflected irradiance is taken as the spectral albedo of each sampling point; Calculate the average value of the spectral albedo to obtain the snow albedo of the scanned area; By combining the operating wavelength of the laser device with the snow albedo, the theoretical echo intensity benchmark of the laser pulse on the glacier surface under the current snow cover condition is calculated. Using the theoretical echo intensity benchmark, the criteria for determining near-ground snow and fog interference peaks are established.

3. The method for acquiring glacier surface laser scanning data based on weather regulation as described in claim 1, characterized in that, The method involves combining the parameter sequence to identify echo peaks belonging to the glacier surface, and, based on the judgment criteria, identifying near-surface snow fog interference peaks located in front of the echo peaks and with intensity values ​​exceeding those of the echo peaks, including: The parameter sequence received by the laser device is acquired, and the discrete sequences of distance and intensity are extracted from the parameter sequence; Correct and remove the background noise in the discrete sequence to obtain the net echo intensity sequence; Retrieve echo peaks that match the corresponding morphological characteristics of the glacier surface from the net echo intensity sequence, and determine the peak value of the echo peaks; Using the radial distance of the echo peak as the dividing boundary, the front end interval of the net echo intensity sequence is taken as the search range of near-ground snow and fog interference peaks; Based on the aforementioned criteria, near-ground snow and fog interference peaks are identified from the search range.

4. The method for acquiring glacier surface laser scanning data based on weather regulation as described in claim 3, characterized in that, The step of determining the radial distance corresponding to the near-ground snow fog interference peak as the upper boundary thickness of the near-ground snow fog layer in the scanning area includes: Verify the waveform characteristics of the near-ground snow and fog interference peak in the net echo intensity sequence; Based on the waveform characteristics, it was confirmed that the near-ground snow fog interference peak originated from Mie scattering of suspended snow crystal particles within the near-ground snow fog layer, rather than from other non-target scattering sources. Based on the current pitch angle of the laser device, the radial distance is decomposed by slant range projection in the vertical direction to obtain the vertical elevation component of the interference peak relative to the horizontal plane where the laser device is located. The vertical elevation component is defined as the upper boundary thickness of the near-ground snow and fog layer.

5. The method for acquiring glacier surface laser scanning data based on weather regulation as described in claim 1, characterized in that, The step of designing the minimum pitch angle that allows the main lobe of the laser device to avoid the near-ground snow and fog layer, based on the thickness of the upper boundary and the installation height of the laser device, includes: The upper boundary thickness is converted into a radial safety avoidance lower limit along the scanning direction of the laser device; The laser beam divergence angle and near-field Rayleigh length are introduced from the factory-issued optical parameters of the laser device. Based on the laser beam divergence angle and the near-field Rayleigh length, calculate the vertical spot radius expansion of the laser main lobe at the radial safety avoidance lower limit in the laser device; The vertical spot radius expansion is taken as a safety margin and added to the upper boundary thickness to obtain the vertical clearance height requirement. By inverting the trigonometric geometric relationship between the required vertical clearance height and the installation height of the laser device, the minimum pitch angle required for the laser main lobe to avoid the near-ground snow and fog layer is derived. Based on the angular resolution limitation of the servo mechanism in the laser device, the minimum pitch lift angle is rounded up to obtain the minimum pitch lift angle.

6. The method for acquiring glacier surface laser scanning data based on weather regulation as described in claim 5, characterized in that, The process of acquiring the cold radiation inversion gradient above the glacier surface during the horizontal reciprocating scan of the laser device includes: Before the laser device begins scanning, a vertically layered array of temperature sensors is installed above the glacier surface. During the horizontal reciprocating scan performed by the laser device, the air temperature sensor array is synchronously triggered to continuously sample the temperature and obtain the instantaneous air temperature value. Arrange the instantaneous air temperature values ​​at the same timestamp along the vertical direction to obtain the instantaneous temperature vertical profile above the glacier surface; The temperature difference between two adjacent height levels above the glacier surface is analyzed, and the ratio of the two temperature differences is calculated to obtain the vertical temperature gradient value. The vertical temperature gradient value is defined as the cold radiation inversion gradient.

7. The method for acquiring glacier surface laser scanning data based on weather regulation as described in claim 1, characterized in that, The step of predicting the vertical diffusion trend of the near-ground snow fog layer based on the temperature inversion gradient, correcting the judgment criterion based on the vertical diffusion trend, and monitoring whether the near-ground snow fog interference peak dissipates based on the second-corrected judgment criterion includes: The instantaneous value of the cold radiation inversion temperature gradient is used to identify the turbulent kinetic energy supply state in the vertical direction of the near-ground snow and fog layer; The turbulent kinetic energy supply state is divided into two types of turbulent development modes: buoyancy suppression-dominated and shear generation-awakening. Based on the two types of turbulence development modes, the relative strengths and weaknesses of the gravity settling flux and turbulent entrainment flux of snow crystal particles in the vertical direction in the near-ground snow fog layer are inferred. Based on the aforementioned win-loss relationship, predict the evolution trajectory of the upper boundary thickness of the near-ground snow fog layer; Determine the direction of evolution of the evolution trajectory, and modify the judgment criteria based on the vertical distribution change of particle concentration implied by the evolution direction; According to the revised judgment criteria, during the subsequent horizontal reciprocating scanning cycle, interference peaks are determined for each laser pulse to obtain the dissipation result of the near-ground snow fog interference peaks.

8. The method for acquiring glacier surface laser scanning data based on weather regulation as described in claim 7, characterized in that, When the near-ground snow fog interference peak has not dissipated, raising the pitch angle of the laser device to the minimum pitch angle to obtain the actual pitch angle value includes: Read the dissipation result; if the result is that the dissipation has not occurred, generate a pitch angle lift trigger command. The minimum pitch angle is set as the target position command value of the pitch servo mechanism in the laser device; The pitch servo mechanism is driven with the target position command value as the driving target to obtain the actual pitch angle value.

9. The method for acquiring glacier surface laser scanning data based on weather regulation as described in claim 1, characterized in that, The process of acquiring data using the actual pitch angle value and spatially stitching the acquired point cloud data with the pitch angle before lifting to obtain a continuous point cloud includes: Based on the actual pitch angle value, the laser device is controlled to perform supplementary scanning on the spatial area within the scanning area that has not yet been acquired, to obtain the original point cloud data, and the initial point cloud data before lifting is recorded simultaneously. Using the optical center of the laser device as the origin and the horizontal plane as the reference plane, a local Cartesian coordinate system is constructed by combining the radial distance value, horizontal azimuth angle value and original pitch angle value of each laser foot point in the initial point cloud data, so as to obtain the local Cartesian point cloud set before lifting. The original point cloud data is transformed into Cartesian coordinates to obtain a local Cartesian point cloud set after lifting, and the overlapping parts in the merging result are removed to obtain a continuous point cloud.

10. A weather-modulated glacier surface laser scanning data acquisition system, used to implement the weather-modulated glacier surface laser scanning data acquisition method according to any one of claims 1-9, characterized in that, The system includes: The determination module is used to emit laser pulses into the scanning area along the pitch angle direction of the laser device, and encapsulate the distance and intensity received when the laser pulses return into a parameter sequence, collect the snow albedo of the glacier surface in the scanning area at the current moment, and combine the snow albedo to determine the determination criteria for identifying near-ground snow fog interference peaks; The upper boundary analysis module is used to identify echo peaks belonging to the glacier surface by combining the parameter sequence, and to identify near-ground snow fog interference peaks located in front of the echo peaks and whose intensity values ​​exceed those of the echo peaks according to the judgment criteria. The radial distance corresponding to the near-ground snow fog interference peaks is determined as the upper boundary thickness of the near-ground snow fog layer in the scanning area. The elevation angle determination module is used to design the minimum pitch elevation angle that allows the main lobe of the laser device to avoid the near-ground snow and fog layer, based on the thickness of the upper boundary and the installation height of the laser device. The dissipation judgment module is used to collect the cold radiation inversion gradient above the glacier surface during the horizontal reciprocating scanning process of the laser device, predict the vertical diffusion trend of the near-ground snow fog layer based on the inversion gradient, correct the judgment criterion based on the vertical diffusion trend, and monitor whether the near-ground snow fog interference peak dissipates based on the second corrected judgment criterion. The actual pitch angle determination module is used to raise the pitch angle of the laser device to the minimum pitch lift angle when the near-ground snow fog interference peak has not dissipated, so as to obtain the actual pitch angle value. The continuous point cloud rendering module is used to complete the acquisition with the actual pitch angle value, and spatially stitch the acquired point cloud data with the pitch angle before lifting to obtain a continuous point cloud.

Images