Satellite laser height measurement positioning method and device under complex terrain and electronic equipment

Abstract

The invention provides a satellite laser height measurement positioning method and device in a complex terrain and electronic equipment, and belongs to the field of satellite laser positioning. The method comprises the following steps: acquiring a footprint image of a to-be-measured laser footprint, a laser echo signal and a corresponding image point coordinate of the to-be-measured laser footprint in the footprint image; performing image segmentation on the footprint image to obtain a ground object segmentation image, constructing a multi-component echo energy model according to the laser echo signal, and determining an optimal Gaussian component according to the ground object segmentation image, the multi-component echo energy model and the image point coordinates; and solving a height measurement positioning result according to the optimal Gaussian component. According to the invention, in satellite laser height measurement in a mode of a full-waveform laser altimeter and a laser footprint camera, Gaussian components can be flexibly selected by carrying out image segmentation on a footprint image to obtain a ground feature segmentation image, and nearest Gaussian components of satellite laser height measurement in various complex terrains can be effectively selected. And the error of satellite laser height measurement is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the field of satellite laser positioning technology, and in particular to a satellite laser altimetry positioning method, device and electronic equipment under complex terrain. Background Art

[0002] Satellite laser altimetry, as an active remote sensing technology, provides a new satellite remote sensing observation method for human beings. By measuring the round-trip time of the laser emitted by the laser from the satellite to the ground, combined with the orbital position and attitude of the satellite platform, the target surface elevation information with decimeter or even centimeter accuracy can be calculated. Among them, the laser altimetry system in the full waveform laser altimeter plus laser footprint camera mode is currently an advanced laser altimeter mode. It can emit laser beams and fully record the echo signal of the ground objects, and can simultaneously collect the ground object images in the area near the laser footprint. By measuring the round-trip time of the laser emitted by the laser from the satellite to the ground, combined with the orbital position, attitude and laser pointing of the satellite platform, the surface elevation information at the laser footprint can be calculated. However, in the satellite laser altimeter system, the satellite laser altimeter emits laser pulses to the surface. After the laser reaches the surface, the footprint diameter can reach tens of meters. The footprint of the satellite laser altimeter may contain a variety of characteristic objects, such as exposed surface, buildings, trees and rivers. The superposition of multiple characteristic objects will lead to inconsistent heights of objects within the footprint range. The full-waveform satellite laser altimeter can fully record the echo of the features of the footprint. Various features will cause the echo waveform to present a multi-peak state. Therefore, in satellite laser altimetry under complex terrain, determining the optimal Gaussian component corresponding to the laser ranging vector is the basis for ensuring the accuracy of satellite laser altimetry positioning.

[0003] In the process of determining the best echo component for complex terrain, the prior art usually determines the best echo component based on experience. The current selection methods include: selecting the last Gaussian component of the echo waveform decomposition, that is, using the time center of gravity parameters of the Gaussian component with the largest time center of gravity among the Gaussian component parameters to calculate the distance from the satellite to the target; selecting the second to last Gaussian component, that is, using the time center of gravity parameters of the Gaussian component with the second largest time center of gravity among the Gaussian component parameters to calculate the distance from the satellite to the target; selecting the Gaussian component with the largest amplitude, that is, using the time center of gravity parameters of the Gaussian component with the largest amplitude among the Gaussian component parameters to calculate the distance from the satellite to the target; selecting the Gaussian component with the largest integral area (indirectly equivalent to the echo energy), that is, using the time center of gravity parameters of the Gaussian component with the largest integral area among the Gaussian components to calculate the distance from the satellite to the target. However, the morphological characteristics of the satellite laser altimetry echo waveform are not only related to the distribution of the height of the objects within the footprint range, but also closely related to the plane position distribution of the characteristic objects of different heights within the footprint, the reflectivity of different characteristic objects, and the geometric morphology of the characteristic objects. It is difficult to accurately select the optimal Gaussian component corresponding to the emitted laser vector based only on a certain waveform characteristic parameter, resulting in large errors in satellite laser altimeter positioning in the full-waveform laser altimeter plus laser footprint camera mode.

[0004] Therefore, the existing technology has the problem that in satellite laser altimetry, it is difficult to accurately select the optimal Gaussian component corresponding to the emitted laser vector based only on a certain waveform characteristic parameter, resulting in a large elevation error in satellite laser altimetry positioning under complex terrain, which needs to be improved. Summary of the invention

[0005] In view of this, it is necessary to provide a satellite laser altimetry positioning method, device and electronic equipment under complex terrain, which is used to solve the technical problem that it is difficult to accurately select the optimal Gaussian component corresponding to the emitted laser vector based on a certain waveform characteristic parameter in the prior art, resulting in large errors in satellite laser altimetry positioning.

[0006] In order to solve the above problems, on the one hand, the present invention provides a satellite laser altimetry positioning method under complex terrain, comprising: Acquire the footprint image of the laser foot point to be measured, the laser echo signal and the corresponding image point coordinates of the laser foot point to be measured in the footprint image; Perform image segmentation on the footprint image to obtain a ground object segmentation image, construct a multi-component echo energy model based on the laser echo signal, and determine the best Gaussian component based on the ground object segmentation image, the multi-component echo energy model and the image point coordinates; The height measurement and positioning results are solved based on the optimal Gaussian component.

[0007] In a possible implementation, the multi-component echo energy model includes a plurality of echo components, the ground object segmentation image includes a plurality of segmentation sub-images, and the number of the echo components is equal to the number of the segmentation sub-images.

[0008] In a possible implementation, performing image segmentation on the footprint image to obtain a ground object segmentation image includes: The footprint image is segmented according to the pixel brightness information of the footprint image to obtain a ground object segmentation image.

[0009] In a possible implementation, a multi-component echo energy model is constructed according to the laser echo signal, including: Construct the multi-component echo photon equation of the object to be measured according to the laser echo signal; The multi-component echo energy model is obtained by simplifying the multi-component echo photon equation.

[0010] In a possible implementation, determining the best Gaussian component according to the ground object segmentation image, the multi-component echo energy model and the image point coordinates includes: Matching the echo component with the segmentation sub-image to obtain matching information; The best Gaussian component is determined based on the matching information and the image point coordinates.

[0011] In a possible implementation, performing information matching between the echo component and the segmentation sub-image to obtain matching information includes: Determine the integrated area of ​​each echo component according to the multi-component echo energy model, and determine the pixel brightness value of each segmented sub-image according to the ground object segmentation image; The integrated areas are sorted to obtain the sorting information of the echo components, and the pixel brightness values ​​are sorted to obtain the sorting information of the segmented sub-images; Matching information is obtained by matching the echo component sorting information with the segmentation sub-image sorting information.

[0012] In a possible implementation, the satellite laser altimetry positioning method under complex terrain also includes: The segmentation sub-image corresponding to the pixel coordinates is taken as the current sub-image. If the distance between the pixel coordinates and the adjacent sub-image of the current sub-image is less than a preset distance threshold or the difference in pixel brightness between the current sub-image and the adjacent sub-image of the current sub-image is less than a preset brightness threshold, the adjacent sub-image is taken as a candidate sub-image. Determine the surface characteristic parameters of the current sub-image and the surface characteristic parameters of the candidate sub-image according to the multi-component echo energy model; If the surface characteristic parameters of the current sub-image are smaller than the surface characteristic parameters of the candidate sub-image, the laser foot point to be measured is moved to the corresponding area of ​​the candidate sub-image, and the geodetic coordinates of the laser foot point to be measured after the movement are calculated.

[0013] On the other hand, the present invention also provides a satellite laser altimetry positioning device under complex terrain, comprising: A signal acquisition unit, used to acquire a footprint image of the laser foot point to be measured, a laser echo signal and the coordinates of the corresponding image point of the laser foot point to be measured in the footprint image; The best Gaussian component determination unit is used to perform image segmentation on the footprint image to obtain a ground object segmentation image, construct a multi-component echo energy model according to the laser echo signal, and determine the best Gaussian component according to the ground object segmentation image, the multi-component echo energy model and the image point coordinates; The height measurement and positioning solving unit is used to solve the height measurement and positioning result according to the best Gaussian component.

[0014] On the other hand, the present invention also provides an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the above-mentioned satellite laser altimetry positioning method under complex terrain is implemented.

[0015] On the other hand, the present invention also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the above-mentioned satellite laser altimetry positioning method under complex terrain is implemented.

[0016] The beneficial effects of the present invention are as follows: in the satellite laser altimetry positioning method under complex terrain provided by the present invention, firstly, the footprint image of the laser foot point to be measured, the laser echo signal and the corresponding image point coordinates of the laser foot point to be measured in the footprint image are obtained; then, the footprint image is segmented to obtain a ground object segmentation image, a multi-component echo energy model is constructed according to the laser echo signal, and the optimal Gaussian component is determined according to the ground object segmentation image, the multi-component echo energy model and the image point coordinates; finally, the altimetry positioning result is solved according to the optimal Gaussian component. In the satellite laser altimetry, the present invention flexibly selects Gaussian components by performing image segmentation on the footprint image to obtain a ground object segmentation image, and can effectively select the nearest Gaussian component of the satellite laser altimetry under various complex terrains, effectively reducing the error of the satellite laser altimetry. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A schematic diagram of a flow chart of an embodiment of a satellite laser altimetry positioning method under complex terrain provided by the present invention; Figure 2 A real footprint image according to an embodiment of the present invention; Figure 3 is a pixel brightness information image according to an embodiment of the present invention; Figure 4 A schematic diagram of a process for constructing a multi-component echo energy model according to an embodiment of the present invention; Figure 5 A schematic diagram of a process for determining an optimal Gaussian component according to an embodiment of the present invention; Figure 6 A schematic diagram of the information matching process of an embodiment of the present invention; Figure 7 A schematic diagram of a process of moving a laser foot point according to an embodiment of the present invention; Figure 8 A schematic structural diagram of an embodiment of a satellite laser altimetry positioning device under complex terrain provided by the present invention; Fig. 9 A schematic structural diagram of an embodiment of an electronic device provided by the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0020] In the description of the embodiments of the present invention, unless otherwise specified, "multiple" means two or more than two. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" may mean: A exists alone, A and B exist at the same time, and B exists alone.

[0021] The descriptions of "first" and "second" in the embodiments of the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the technical features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0022] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] The present invention provides a satellite laser altimetry positioning method, device and electronic equipment under complex terrain, which are respectively described below.

[0024] Figure 1 The flowchart of an embodiment of the satellite laser altimetry positioning method under complex terrain provided by the present invention is as follows: Figure 1 As shown in the figure, the satellite laser altimetry positioning method under complex terrain includes: S101, obtaining a footprint image of a laser foot point to be measured, a laser echo signal, and corresponding image point coordinates of the laser foot point to be measured in the footprint image; S102, performing image segmentation on the footprint image to obtain a ground object segmentation image, constructing a multi-component echo energy model according to the laser echo signal, and determining the best Gaussian component according to the ground object segmentation image, the multi-component echo energy model and the image point coordinates; S103, solving the height measurement and positioning result according to the optimal Gaussian component.

[0025] Compared with the prior art, the satellite laser altimetry positioning method under complex terrain provided by the embodiment of the present invention first obtains the footprint image of the laser footprint to be measured, the laser echo signal and the corresponding image point coordinates of the laser footprint to be measured in the footprint image; then the footprint image is segmented to obtain a ground object segmentation image, a multi-component echo energy model is constructed according to the laser echo signal, and the optimal Gaussian component is determined according to the ground object segmentation image, the multi-component echo energy model and the image point coordinates; finally, the altimetry positioning result is solved according to the optimal Gaussian component. In the satellite laser altimetry, the present invention flexibly selects Gaussian components by performing image segmentation on the footprint image to obtain a ground object segmentation image, and can effectively select the nearest Gaussian component of the satellite laser altimetry under various complex terrains, effectively reducing the error of the satellite laser altimetry.

[0026] In some embodiments of the present invention, the multi-component echo energy model includes a plurality of echo components, the ground object segmentation image includes a plurality of segmentation sub-images, and the number of the echo components is equal to the number of the segmentation sub-images.

[0027] In some embodiments of the present invention, performing image segmentation on the footprint image to obtain a ground object segmentation image includes: The footprint image is segmented according to the pixel brightness information of the footprint image to obtain a ground object segmentation image.

[0028] Specifically, Figure 2 is a real footprint image of an embodiment of the present invention, Figure 3 is a pixel brightness information image according to an embodiment of the present invention. Figure 2 and Figure 3 As shown in the figure, during the satellite laser altimetry process, the ground objects in the satellite laser altimetry footprint reflect the sunlight after receiving the parallel light from the sun, and are finally received and imaged by the satellite laser altimetry footprint camera, as shown in the figure. Figure 2In the footprint range, the reflectivity of different types of objects (mainly considering the height feature in the embodiment) is different, and the pixel brightness information in the corresponding footprint image is also different, so the following can be obtained: Figure 3 The corresponding pixel brightness information image. In the embodiment, image segmentation is performed by the brightness information of the pixels in the footprint image, so as to classify the different categories of objects in the image. In the image segmentation process, considering that the number of components obtained by waveform decomposition of the laser echo signal in the satellite laser altimetry can reflect the number of features of objects at different heights within the footprint range, the embodiment uses the echo components of the multi-component echo energy model as the number of image segmentation categories, and performs image segmentation on the footprint image according to the pixel brightness information of the footprint image to obtain a number of object segmentation images.

[0029] In some embodiments of the present invention, Figure 4 FIG. 1 is a flow chart of constructing a multi-component echo energy model according to an embodiment of the present invention. Figure 4 As shown, a multi-component echo energy model is constructed according to the laser echo signal, including: S401, constructing a multi-component echo photon equation of the object to be measured according to the laser echo signal; S402, simplifying the multi-component echo photon equation to obtain a multi-component echo energy model.

[0030] Specifically, in the embodiment, the laser emitted by the full-waveform satellite laser altimeter is transmitted through the atmosphere and reflected by the ground target, and then passes through the atmosphere again and is received by the laser receiver. After processes such as photoelectric conversion and gain, the laser echo signal is finally sampled and recorded, and a multi-component echo energy model is established based on this.

[0031] After the noise filtering operation is completed on the full waveform echo of satellite laser altimetry, the echo waveform can be considered as the superposition of multiple Gaussian signals, corresponding to the characteristic objects at different elevations in the laser footprint, and the formula is expressed as:

[0032] in, , and Respectively The amplitude, time centroid and RMS pulse width of the Gaussian components.

[0033] The number of photons contained in the return signal can be expressed as:

[0034] in, is the laser detector gain, is the charge, is the voltage signal, To transmit the pulse energy, is the photon energy, is the receiver aperture area, is the distance from the detector to the target, is the detector optical transmittance, Detector quantum efficiency, is the transmittance of laser in the atmosphere, is the target reflectivity, is the angle between the normal vector of the target reflection surface and the field of view of the telescope.

[0035] in the formula It is the sum of the number of photons contained in the echo pulse. The distribution of the number of photons at different times is the echo waveform of the laser. Under multi-component echo, there are characteristic distributions at different heights in the footprint, resulting in different return times for pulses emitted at the same time. The embodiment divides the terrain within the laser spot into grids or facets , the laser reaches the surface element The propagation distance is expressed as , combined with the above formula, we can It is expressed as the sum of the number of echo photons for each bin (assuming that the noise in the echo has been removed):

[0036] in, Detector to bin The distance from the center coordinates of To emit to the surface element The pulse energy can be expressed as:

[0037] in, represents the RMS value of the laser emission energy distribution within the laser footprint, which is the , For facet The plane position center coordinates, is the plane coordinate of the emitted laser vector direction within the footprint.

[0038] Simplifying the formula, it can be expressed as:

[0039] in In the embodiment, the satellite laser altimeter divergence angle is about 40urad, the orbit altitude is 500-600km, and the footprint diameter is about 20m. Detector to bin The distance between the center coordinates of the footprint. The difference is from several meters to tens of meters. The value itself is 500km level, different facets The difference in values ​​can be ignored, so the formula can be further simplified to:

[0040] It can be seen that within the same footprint, the integrated area of ​​a Gaussian component of the multi-echo component is equivalent to the product of the received pulse energy at the corresponding target, the reflectivity at the target, and the cosine of the scattering angle from the target to the detector field of view.

[0041] In some embodiments of the present invention, Figure 5 FIG. 1 is a flow chart of determining the optimal Gaussian component according to an embodiment of the present invention. Figure 5 As shown, the optimal Gaussian component is determined according to the ground object segmentation image, the multi-component echo energy model and the image point coordinates, including: S501, performing information matching between the echo component and the segmentation sub-image to obtain matching information; S502: Determine the best Gaussian component according to the matching information and the image point coordinates.

[0042] In some embodiments of the present invention, Figure 6 FIG. 1 is a flow chart of information matching according to an embodiment of the present invention. Figure 6 As shown, the echo component is matched with the segmentation sub-image to obtain matching information, including: S601, determining the integral area of ​​each echo component according to the multi-component echo energy model, and determining the pixel brightness value of each segmented sub-image according to the ground object segmentation image; S602, sorting the integrated areas to obtain echo component sorting information, and sorting the pixel brightness values ​​to obtain segmentation sub-image sorting information; S603: Match the echo component sorting information and the segmentation sub-image sorting information to obtain matching information.

[0043] Specifically, based on the ground object segmentation image and multi-component echo energy model obtained in the previous steps, the embodiment can assume that the pixel brightness in the footprint image is equivalent to the product of the reflectivity of the corresponding ground object and the cosine of the scattering angle from the target to the detector field of view. The corresponding pixel brightness on the footprint image is ,common pixels, the multi-component echo energy model can be obtained:

[0044] in, For the The plane position of pixels, For the The area corresponding to the pixel can be simplified as follows:

[0045]

[0046]

[0047] Then, the embodiment can match the integrated area of ​​the echo component with the pixel brightness and position information of the footprint image of the target area to determine the segmentation sub-images corresponding to different echo components. For example, assuming that a certain echo has three echo components , the corresponding integral area is , image segmentation of the footprint image is performed to obtain three segmentation sub-images in the ground feature segmentation image , the corresponding pixel brightness value is After sorting, if ,and , then match according to the sorting, the echo component Corresponding segmentation subgraph , echo component Corresponding segmentation subgraph , echo component Corresponding segmentation subgraph .

[0048] The last embodiment uses the segmented sub-graph where the coordinates of the corresponding image points of the laser height measurement foot points in the footprint image are located, and uses the corresponding echo components as the best Gaussian components to perform height measurement and positioning to obtain the height measurement and positioning results.

[0049] In some embodiments of the present invention, Figure 7 FIG. 1 is a schematic diagram of a process of moving the laser foot point according to an embodiment of the present invention. Figure 7 As shown, the satellite laser altimetry positioning method under complex terrain also includes: S701, taking the segmentation sub-image corresponding to the pixel coordinates as the current sub-image, if the distance between the pixel coordinates and the adjacent sub-image of the current sub-image is less than a preset distance threshold or the difference in pixel brightness between the current sub-image and the adjacent sub-image of the current sub-image is less than a preset brightness threshold, taking the adjacent sub-image as a candidate sub-image; S702, determining the surface characteristic parameters of the current sub-image and the surface characteristic parameters of the candidate sub-image according to the multi-component echo energy model; S703: If the surface characteristic parameters of the current sub-image are smaller than the surface characteristic parameters of the candidate sub-image, the laser foot point to be measured is moved to the corresponding area of ​​the candidate sub-image, and the geodetic coordinates of the laser foot point to be measured after the movement are calculated.

[0050] Specifically, according to the above steps, the present invention provides a method for jointly determining the optimal Gaussian component corresponding to the laser ranging vector under multiple echo components through footprint images and echo waveform parameters, which can effectively improve the avoidance of errors in laser altimetry positioning. However, considering the influence of noise, thin clouds or fog that may be contained in the footprint image, there may be certain errors in image supervision classification, especially pixels located in adjacent edge areas of different categories. At the same time, since the footprint camera's ground imaging band (400-800nm) is inconsistent with the laser altimetry measurement band (1064nm), the reflectivity information of the ground object indirectly expressed by the brightness information of the footprint image may be inconsistent with the reflectivity of the ground object in the laser measurement band, resulting in an incorrect match between the echo waveform decomposition component and the footprint image classification area.

[0051] In order to avoid the impact caused by these errors and provide more reliable laser footprint positioning coordinates, the embodiment of the present invention also includes a method for optimizing the laser footprint coordinates according to the footprint image information and the waveform characteristic parameters of the multi-component echo energy model. If the laser footprint landing position corresponds to the image point position in the footprint image and is located at the edge area of ​​two classification categories of the footprint image or the brightness of different classification areas of the footprint image is relatively close, the laser footprint positioning coordinates are moved to the corresponding area with smaller echo pulse width and larger amplitude. At this time, the Gaussian component with smaller echo pulse width and larger amplitude is used to calculate the laser ranging parameters. The specific process is as follows: Assuming the number of echo components is 3, it can be expressed as , the segmented sub-image of the footprint image is , the mutual matching relationship determined in the previous steps is , the image point in the image corresponding to the laser foot point is located at The edge part of the segmented sub-image area and The segmented sub-image regions are adjacent; According to the echo component parameters in the multi-component echo energy model , Example selection As the surface feature parameter of the segmented sub-image, it provides a reference for the movement of the laser foot point. Move the laser foot point to The area corresponding to the larger segmentation sub-image. represents the amplitude of the echo component, Represents the pulse width of the echo component. The larger the Gaussian component amplitude and the smaller the pulse width, the flatter the corresponding surface feature and the stronger the reflectivity.

[0052] The Gaussian component and the selected surface characteristic parameters can be expressed as , and , the three components correspond to the segmentation sub-graphs , and , the image point in the footprint image corresponding to the laser foot point is located at In the category area, and Category regions are adjacent, if , then move the laser foot point to In the category area, the image point coordinates of the laser foot point in the footprint image are moved simultaneously (at the same time, the geodetic coordinate offset of the laser foot point is calculated according to the image point coordinate offset parameters and the footprint image external parameter parameters), and finally the echo component is selected It is used to calculate the distance from the satellite to the target in the direction of the laser ranging vector, and calculate the geodetic coordinates of the laser foot point after movement.

[0053] In order to verify the effectiveness of the embodiments of the present invention, the embodiments experimentally compare the scheme of the present invention with the prior art. The experimental area covers 50°21′N to 52°30′N, 6°E to 9°23′E, with an area of ​​approximately 34,080 square kilometers. The area contains a variety of landforms, such as plains, hills, mountains and canyons. The lowest altitude is -293 meters, the highest is 843.2 meters, and the average altitude is 109 meters. The experimental data includes GF-7 laser altimetry data and high-precision airborne point cloud data. The average spatial resolution of the point cloud is 1m, and the plane and elevation accuracies are 0.5m and 0.2m respectively.

[0054] In order to verify the effectiveness and evaluate the accuracy of the satellite laser altimetry positioning method under complex terrain proposed in the present invention, the comparative experiment selected four typical methods for comparison: the echo components used for ranging parameter solution were first selected using different methods, and then the coordinates of the laser altimetry foot points were calculated, and finally the high-precision airborne point cloud was used to evaluate the elevation accuracy of the foot point positioning. For ease of comparison, this article marks the different component selection methods as follows: The last Gaussian component - Last Gaussian (LastG); The second to last Gaussian component - Penult Gaussian (PenultG); Gaussian with maximum amplitude (MaxAmpG); Gaussian with maximum area (MaxAreaG); The satellite laser altimetry positioning method established in this scheme is Gaussian with graph cut and shift (GraphCutG_Shift).

[0055] In the experimental area, the number of laser height measurement points with 2, 3 and 4 echo decomposition components is 52, 29 and 15 respectively, of which the number of laser points collected by the first laser is 46 and the number of laser points collected by the second laser is 50. In order to avoid the verification error caused by the time interval between the acquisition of airborne laser point cloud and laser height measurement data, this paper will only evaluate the accuracy of laser height measurement points (65 in total) that fall in non-forest areas. The results are shown in Tables 1 and 2, where Table 1 is the elevation accuracy evaluation table of the multi-echo component laser height measurement foot point positioning of the first laser, and Table 2 is the elevation accuracy evaluation table of the multi-echo component laser height measurement foot point positioning of the second laser.

[0056] Table 1

[0057] Table 2

[0058] According to Table 1 and Table 2, which are the evaluation results of the elevation accuracy of the laser height measurement foot point positioning under the multi-echo components collected by laser 1 and laser 2 in the experimental area, it can be found that: when the number of Gaussian components of the echo decomposition is 2 or 3, the laser distance measurement component determination and foot point coordinate optimization method in the present invention has the best laser foot point elevation accuracy, which is better than the existing typical method; however, when the number of components is 4, the accuracy of the method is degraded; However, it can also be found that in the experimental area, when the number of echo decomposition components is two, the corresponding maximum elevation error of the laser footprint positioning of the method in this paper still reaches 2.13m. After analyzing the terrain in the laser footprint and the laser footprint image, it is found that some areas in the footprint image are blocked by clouds and fog, resulting in errors in the classification of the laser footprint image features, which ultimately leads to the incorrect selection of the laser ranging component.

[0059] In summary, the satellite laser altimetry positioning method under complex terrain provided by the present invention first obtains the footprint image of the laser footprint to be measured, the laser echo signal and the corresponding image point coordinates of the laser footprint to be measured in the footprint image; then the footprint image is segmented to obtain a ground object segmentation image, a multi-component echo energy model is constructed according to the laser echo signal, and the optimal Gaussian component is determined according to the ground object segmentation image, the multi-component echo energy model and the image point coordinates; finally, the altimetry positioning result is solved according to the optimal Gaussian component. In the satellite laser altimetry, the present invention flexibly selects Gaussian components by performing image segmentation on the footprint image to obtain a ground object segmentation image, and can effectively select the nearest Gaussian component of the satellite laser altimetry under various complex terrains, effectively reducing the error of the satellite laser altimetry.

[0060] In order to better implement the satellite laser altimetry positioning method under complex terrain in the embodiment of the present invention, based on the satellite laser altimetry positioning method under complex terrain, correspondingly, Figure 8 As shown, the present invention also provides a satellite laser altimetry positioning device under complex terrain, and the satellite laser altimetry positioning device 800 under complex terrain includes: The signal acquisition unit 801 is used to acquire the footprint image of the laser foot point to be measured, the laser echo signal and the corresponding image point coordinates of the laser foot point to be measured in the footprint image; The best Gaussian component determination unit 802 is used to perform image segmentation on the footprint image to obtain a ground object segmentation image, construct a multi-component echo energy model according to the laser echo signal, and determine the best Gaussian component according to the ground object segmentation image, the multi-component echo energy model and the image point coordinates; The altimetry positioning solving unit 803 is used to solve the altimetry positioning result according to the best Gaussian component.

[0061] The satellite laser altimetry positioning device 800 for complex terrain provided in the above embodiment can implement the technical solution described in the above embodiment of the satellite laser altimetry positioning method for complex terrain. The specific implementation principles of the above modules or units can refer to the corresponding contents in the above embodiment of the satellite laser altimetry positioning method for complex terrain, which will not be repeated here.

[0062] like Fig. 9 As shown, the present invention also provides an electronic device 900. The electronic device 900 includes a processor 901, a memory 902 and a display 903. Fig. 9 Only some components of the electronic device 900 are shown, but it should be understood that it is not required to implement all of the components shown, and more or fewer components may be implemented instead.

[0063] In some embodiments, the processor 901 may be a central processing unit (CPU), a microprocessor or other data processing chip, used to run program codes or process data stored in the memory 902, such as the satellite laser altimetry positioning method under complex terrain in the present invention.

[0064] In some embodiments, the processor 901 may be a single server or a server group. The server group may be centralized or distributed. In some embodiments, the processor 901 may be local or remote. In some embodiments, the processor 901 may be implemented in a cloud platform. In one embodiment, the cloud platform may include a private cloud, a public cloud, a hybrid cloud, a community cloud, a distributed cloud, an internal cloud, a multi-cloud, etc., or any combination thereof.

[0065] In some embodiments, the memory 902 may be an internal storage unit of the electronic device 900, such as a hard disk or memory of the electronic device 900. In other embodiments, the memory 902 may also be an external storage device of the electronic device 900, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the electronic device 900.

[0066] Furthermore, the memory 902 may include both an internal storage unit of the electronic device 900 and an external storage device. The memory 902 is used to store application software installed in the electronic device 900 and various data.

[0067] In some embodiments, the display 903 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, an OLED (Organic Light-Emitting Diode) touch device, etc. The display 903 is used to display information of the electronic device 900 and to display a visual user interface. The components 901-903 of the electronic device 900 communicate with each other through a system bus.

[0068] In one embodiment, when the processor 901 executes the satellite laser altimetry positioning program under complex terrain in the memory 902, the following steps may be implemented: Acquire the footprint image of the laser foot point to be measured, the laser echo signal and the corresponding image point coordinates of the laser foot point to be measured in the footprint image; Perform image segmentation on the footprint image to obtain a ground object segmentation image, construct a multi-component echo energy model based on the laser echo signal, and determine the best Gaussian component based on the ground object segmentation image, the multi-component echo energy model and the image point coordinates; The height measurement and positioning results are solved based on the optimal Gaussian component.

[0069] It should be understood that: when the processor 901 executes the satellite laser altimetry positioning program under complex terrain in the memory 902, in addition to the above functions, other functions can also be implemented. For details, please refer to the description of the corresponding method embodiment above.

[0070] Accordingly, an embodiment of the present application also provides a computer-readable storage medium, which is used to store computer-readable programs or instructions. When the program or instructions are executed by a processor, it can implement the steps or functions of the satellite laser altimetry positioning method under complex terrain provided by the above-mentioned method embodiments.

[0071] Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware (such as a processor, a controller, etc.) through a computer program, and the computer program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

[0072] The satellite laser altimetry positioning method, device, electronic device and storage medium under complex terrain provided by the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A satellite laser altimetry positioning method under complex terrain, characterized in that: include: Acquire a footprint image of a laser foot point to be measured, a laser echo signal, and the coordinates of a corresponding image point of the laser foot point to be measured in the footprint image; Performing image segmentation on the footprint image to obtain a ground object segmentation image, constructing a multi-component echo energy model according to the laser echo signal, and determining an optimal Gaussian component according to the ground object segmentation image, the multi-component echo energy model and the image point coordinates; The altimetry positioning result is solved according to the optimal Gaussian component.

2. The satellite laser altimetry positioning method under complex terrain according to claim 1, characterized in that: The multi-component echo energy model includes a plurality of echo components, the ground object segmentation image includes a plurality of segmentation sub-images, and the number of the echo components is equal to the number of the segmentation sub-images.

3. The satellite laser altimetry positioning method under complex terrain according to claim 2, characterized in that: The step of performing image segmentation on the footprint image to obtain a ground object segmentation image includes: The footprint image is segmented according to the pixel brightness information of the footprint image to obtain a ground object segmentation image.

4. The satellite laser altimetry positioning method under complex terrain according to claim 2, characterized in that: The constructing a multi-component echo energy model according to the laser echo signal comprises: Constructing a multi-component echo photon equation of the object to be measured according to the laser echo signal; The multi-component echo photon equation is simplified to obtain a multi-component echo energy model.

5. The satellite laser altimetry positioning method under complex terrain according to claim 1, characterized in that: The determining of the optimal Gaussian component according to the ground object segmentation image, the multi-component echo energy model and the image point coordinates includes: Performing information matching between the echo component and the segmented sub-image to obtain matching information; An optimal Gaussian component is determined according to the matching information and the image point coordinates.

6. The satellite laser altimetry positioning method under complex terrain according to claim 5, characterized in that: The step of performing information matching between the echo component and the segmented sub-graph to obtain matching information includes: Determining the integrated area of ​​each of the echo components according to the multi-component echo energy model, and determining the pixel brightness value of each of the segmented sub-images according to the ground object segmentation image; Sorting the integrated areas to obtain echo component sorting information, and sorting the pixel brightness values ​​to obtain segmentation sub-image sorting information; The echo component sorting information and the segmentation sub-image sorting information are matched to obtain matching information.

7. The satellite laser altimetry positioning method under complex terrain according to claim 6, characterized in that: The method further comprises: The segmented sub-image corresponding to the pixel coordinates is used as the current sub-image. If the distance between the pixel coordinates and the adjacent sub-image of the current sub-image is less than a preset distance threshold or the difference in pixel brightness between the current sub-image and the adjacent sub-image of the current sub-image is less than a preset brightness threshold, the adjacent sub-image is used as a candidate sub-image. Determining the surface characteristic parameters of the current sub-image and the surface characteristic parameters of the candidate sub-image according to the multi-component echo energy model; If the surface characteristic parameters of the current sub-image are smaller than the surface characteristic parameters of the candidate sub-image, the laser foot point to be measured is moved to the corresponding area of ​​the candidate sub-image, and the geodetic coordinates of the laser foot point to be measured after the movement are calculated.

8. A satellite laser altimetry positioning device under complex terrain, characterized in that: include: A signal acquisition unit, used to acquire a footprint image of a laser foot point to be measured, a laser echo signal and the coordinates of a corresponding image point of the laser foot point to be measured in the footprint image; an optimal Gaussian component determination unit, configured to perform image segmentation on the footprint image to obtain a ground object segmentation image, construct a multi-component echo energy model according to the laser echo signal, and determine an optimal Gaussian component according to the ground object segmentation image, the multi-component echo energy model and the image point coordinates; The altimetry and positioning solving unit is used to solve the altimetry and positioning result according to the optimal Gaussian component.

9. An electronic device comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the satellite laser altimetry positioning method under complex terrain according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the satellite laser altimetry positioning method under complex terrain according to any one of claims 1 to 7 is implemented.

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