A method for detecting blind areas and geometric overlapping areas of atmospheric laser radar

Abstract

The present invention belongs to the technical field of laser radar, and in particular, relates to a method for detecting blind areas and geometric overlapping areas of atmospheric laser radar. The detection method comprises the following steps: setting a scanning device vertically to the ground, scanning atmospheric concentration data, and obtaining vertical scanning atmospheric data; setting the scanning device at different inclination angles, scanning atmospheric concentration data, and obtaining oblique atmospheric data; obtaining data in the laser radar blind area and geometric factor overlapping area from the oblique atmospheric data to replace the data of the corresponding height in the vertical scanning atmospheric data. The present invention can improve the accuracy of near-ground atmospheric detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser radar, and in particular relates to a method for detecting blind areas and geometric overlapping areas of an atmospheric laser radar. Background Art

[0002] LiDAR uses laser as its light source and remotely senses the atmosphere by detecting the radiation signal after the interaction between laser and the atmosphere, thereby achieving real-time inversion of parameter profiles of atmospheric components.

[0003] The blind area and geometric factor of LiDAR are system parameters unique to LiDAR. Figure 1 The schematic diagram of the atmospheric lidar blind area and the overlapping area of ​​the geometric factor is shown in Figure 1 As shown, the transmitting system 1 emits a fan-shaped laser vertically upward from the ground, and the area where the receiving system 2 receives the radiation signal is also fan-shaped. The radiation signal is divided into three areas, namely, the radar blind area D, the geometric factor overlapping area E and the radar full reception area F.

[0004] The formation of laser radar blind area and geometric factor is due to the fact that the receiving optical telescope's receiving field of view is near the ground, while the upper area can only partially receive the laser atmospheric back radiation without generation. In other words, due to structural reasons, the laser energy emitted in the laser radar equation is not a constant in the range above the ground. Each laser radar has its own blind area and geometric factor. Due to the geometric factors and blind areas of the laser radar, it is impossible to accurately detect the near-ground atmosphere. Therefore, there is an urgent need for a detection method for the blind area and geometric overlap area of ​​the atmospheric laser radar to ensure the accuracy of near-ground atmospheric detection. Summary of the invention

[0005] In order to improve the accuracy of near-ground atmospheric detection data, the present invention proposes a detection method for the blind area and geometric overlap area of ​​an atmospheric lidar. The specific scheme is as follows:

[0006] A method for detecting blind areas and geometric overlapping areas of an atmospheric laser radar, the laser radar detection method comprising the following steps:

[0007] The scanning device is set vertically on the ground to scan the atmospheric concentration data to obtain vertical scanning atmospheric data;

[0008] The scanning device is set at different tilt angles to scan the atmospheric concentration data and obtain the oblique atmospheric data;

[0009] The data in the laser radar blind area and the overlapping area of ​​the geometric factor are obtained from the slant range atmospheric data to replace the data of the corresponding height in the vertical scanning atmospheric data.

[0010] Furthermore, the scanning device is set at different tilt angles to scan the atmospheric concentration data, and obtaining the oblique atmospheric data specifically includes the following steps:

[0011] Obtain the geometric factor b and horizontal effective detection distance L of the laser radar;

[0012] Set the value of the scanning device pitch angle to α , scan the near-ground atmosphere and obtain slant atmospheric data. At this time, the effective detection height in the vertical direction is Lsina , geometric factor bsina ;

[0013] The method of obtaining data in the laser radar blind area and the overlapping area of ​​the geometric factor from the oblique range atmospheric data to replace the data of the corresponding height in the vertical scanning atmospheric data specifically comprises the following steps:

[0014] like Lsina The value is not less than the geometric factor b, the scan is completed, and the vertical height range is bsina~b In the area, the results of this scan will replace the atmospheric concentration data of the corresponding height obtained by vertical scanning;

[0015] like Lsina The value is less than the geometric factor b， Continue with the tilt scan.

[0016] Furthermore, if Lsina The value is less than the geometric factor b， Continuing the tilt scan specifically includes the following steps:

[0017] like Lsina The value is less than the geometric factor b , increase the pitch angle of the scanning device, denoted as β, where β>α; Rescan to get β Slant atmospheric concentration data at angles;

[0018] In vertical height range bsina~Lsina In the area, the atmospheric concentration data of the corresponding height obtained by vertical scanning is replaced by the last scanning data;

[0019] In vertical height range Lsinα~Lsinβ In the area, the scan result will replace the atmospheric concentration data of the corresponding height obtained by vertical scanning.

[0020] Furthermore, the vertical height range Lsinα~Lsinβ In the area, after replacing the atmospheric concentration data of the corresponding height obtained by vertical scanning with the scanning result, the following steps are also included:

[0021] Compare Lsinβ and b The numerical value of

[0022] like Lsinβ≥b , the scan is complete; if Lsinβ<b , the pitch angle of the scanning device is continued to be increased to scan the atmospheric concentration data, and the atmospheric concentration data of the radar blind area and the geometric factor overlapping area that have not been replaced are replaced until the effective detection height of the scanning angle in the vertical direction is greater than the geometric factor b .

[0023] Furthermore, the scanning device is set at different tilt angles to scan the atmospheric concentration data, and obtaining the oblique atmospheric data specifically includes the following steps:

[0024] According to mathematical formula sinC=b / L Find the maximum tilt angle of the scanning device C ,in b represents the value of the laser radar geometry factor, L Indicates the effective detection distance of the scanning device in the horizontal direction;

[0025] Take the minimum tilt angle α , at an inclination angle α~C Take several tilt angle values ​​within the range, among which the minimum tilt angle α Infinitely approaching 0;

[0026] Adjust the scanning device according to the tilt angle value and the maximum tilt angle. C The atmosphere is scanned multiple times to obtain multiple sets of slant atmospheric data.

[0027] Furthermore, the step of obtaining data in the laser radar blind area and the overlapping area of ​​the geometric factor from the oblique range atmospheric data to replace the data of the corresponding height in the vertical scanning atmospheric data specifically includes the following steps:

[0028] The data in the laser radar blind area and the overlapping area of ​​the geometric factor are obtained from multiple sets of slant-range atmospheric data to replace the data in the vertical scanning atmospheric data. If there is overlapping data in the multiple sets of slant-range atmospheric data in the overlapping area of ​​the radar blind area and the geometric factor during the replacement process, the data measured when the inclination angle is the smallest is used.

[0029] Furthermore, when the scanning device performs tilted scanning, the spatial resolution of the scanning device needs to be adjusted to the product of the spatial resolution during vertical scanning and the sine value of the tilt angle.

[0030] In another embodiment of the present invention, a detection device for an atmospheric laser radar blind area and a geometric overlap area is also disclosed, the detection device comprising a laser radar, a scanning device, and a computing unit;

[0031] The laser radar is used to emit a laser beam into the atmosphere and receive radiation signals generated by the interaction between the laser beam and the atmosphere, and transmit the signals to the computing unit;

[0032] The scanning device is used to change the transmission and reception directions;

[0033] The calculation unit is used to execute the method for detecting blind spots and geometric overlapping areas of atmospheric laser radar described in any one of the above embodiments.

[0034] In another embodiment of the present invention, a computer-readable storage medium is disclosed, on which a computer program is stored. When the computer program is run, a method for detecting blind spots and geometric overlapping areas of an atmospheric laser radar as described in any one of the above embodiments is executed.

[0035] In another embodiment of the present invention, there is also disclosed a processor and a storage medium, on which a computer program is stored. The processor reads and runs the computer program from the storage medium to execute a method for detecting blind spots and geometric overlapping areas of an atmospheric lidar as described in any one of the above embodiments.

[0036] The beneficial effect of the present invention is that it can accurately measure the atmospheric concentration data of the laser radar blind area and the area where the geometric factor overlaps, thereby increasing the credibility of the data. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic diagram of an atmospheric laser radar transmitting system and a receiving system is shown;

[0038] Figure 2 A flow chart showing a method for detecting blind areas and geometric overlapping areas of an atmospheric laser radar in an embodiment of the present invention is shown;

[0039] Figure 3 A schematic diagram of the structure of a detection device for blind areas and geometric overlapping areas of an atmospheric laser radar proposed by the present invention;

[0040] Figure 4-7 In the embodiment of the present invention, the scanning device at different tilt angles is used to obtain the concentration of a certain component gas in the atmosphere.

[0041] In the figure: 1. Transmitting system; 2. Receiving system; 3. LiDAR; 4. Scanning device. DETAILED DESCRIPTION

[0042] like Figure 2 As shown, the present invention discloses a method for detecting blind areas and geometric overlapping areas of an atmospheric laser radar, the detection method comprising the following steps:

[0043] The scanning device 4 is arranged vertically on the ground to scan the atmospheric concentration data to obtain vertical scanning atmospheric data;

[0044] The scanning device 4 is set at different tilt angles to scan the atmospheric concentration data and obtain the oblique atmospheric data;

[0045] The data in the laser radar blind area and the overlapping area of ​​the geometric factor are obtained from the slant range atmospheric data to replace the data of the corresponding height in the vertical scanning atmospheric data.

[0046] Specifically, when the scanning device 4 is set vertically upward and measures the concentration of a certain gas in the atmosphere, although there is data in the laser radar blind area and the overlapping area of ​​the geometric factor, the data in this area is inaccurate. Therefore, it is necessary to re-measure the data in this area. Therefore, in the present invention, the scanning is set to be tilted. After the tilt setting, although the scanning range in the vertical height is reduced, the low-altitude atmospheric data obtained by the tilted scanning is relatively accurate. Then, in the overlapping area of ​​the geometric factor, the oblique atmospheric data obtained by the tilted scanning replaces the data obtained by the vertical scanning, and complete and accurate atmospheric concentration data can be obtained.

[0047] Furthermore, the scanning device 4 is set at different tilt angles to scan the atmospheric concentration data, and obtaining the oblique atmospheric data specifically includes the following steps:

[0048] Get the geometry factor of LiDAR 3 b And horizontal effective detection distance L ;

[0049] Set the value of the pitch angle of the scanning device 4 to α , scan the near-ground atmosphere and obtain slant atmospheric data. At this time, the effective detection height in the vertical direction is Lsina , geometric factor bsina ;

[0050] The method of obtaining data in the laser radar blind area and the overlapping area of ​​the geometric factor from the oblique range atmospheric data to replace the data of the corresponding height in the vertical scanning atmospheric data specifically comprises the following steps:

[0051] like Lsina The value is not less than the geometric factor b, the scan is completed, and the vertical height range is bsina~b In the area, the results of this scan will replace the atmospheric concentration data of the corresponding height obtained by vertical scanning;

[0052] like Lsina The value is less than the geometric factor b， Continue with the tilt scan.

[0053] Specifically, the scanning device 4 is tilted at a small angle relative to the vertical direction. α, at this time, the scanning device 4 can scan the overlapping area of ​​the geometric factors, and the data is relatively accurate. At this time, the effective detection height in the vertical direction Lsina .Compare Lsina and geometric factors b If the effective detection height is greater than the geometric factor, it means that α At this angle, the atmospheric concentration data in the laser radar blind area and the overlapping area of ​​the geometric factor have been measured. bsina~b In this area, the atmospheric concentration data measured this time is used to replace the atmospheric concentration data obtained by vertical scanning. α The smaller the angle, the bsina Also very small ， In actual measurement experiments, it can be ignored.

[0054] Furthermore, if Lsina The value is less than the geometric factor b， Continuing the tilt scan specifically includes the following steps:

[0055] like Lsina The value is less than the geometric factor b , increase the pitch angle of the scanning device 4, denoted as β, where β>α; Rescan to get β Slant atmospheric concentration data at angles;

[0056] In vertical height range bsina~Lsina In the area, the atmospheric concentration data of the corresponding height obtained by vertical scanning is replaced by the last scanning data;

[0057] In vertical height range Lsinα~Lsinβ In the area, the scan result will replace the atmospheric concentration data of the corresponding height obtained by vertical scanning.

[0058] Specifically, when the angle is α When scanning, due to α The angle is too small, resulting in the effective detection height in the vertical direction Lsina is less than the geometric factor, so that this scan cannot completely measure the atmospheric concentration data of the geometric factor overlapping area. In order to measure the remaining geometric factor overlapping area, continue to increase the tilt angle of the scanning device 4 α Rescan ， The inclination angle at this time is recorded as β The smaller the inclination angle, the more accurate the measured data. bsina~Lsina In the first scan, the results are used. Lsinα~LsinβThe current scanning result is used to replace the atmospheric concentration data obtained by vertical scanning. It is worth noting that the minimum angle of the pitch angle scanning device 4 relative to the vertical direction is Figure 1 The angle at which the ellipsis is located.

[0059] Furthermore, the vertical height range Lsinα~Lsinβ In the area, after replacing the atmospheric concentration data of the corresponding height obtained by vertical scanning with the scanning result, the following steps are also included:

[0060] Compare Lsinβ and b The numerical value of

[0061] like Lsinβ≥b , the scan is complete; if Lsinβ<b , the pitch angle of the scanning device 4 is continued to be increased to scan the atmospheric concentration data, and the atmospheric concentration data of the radar blind area and the geometric factor overlapping area that have not been replaced are replaced until the effective detection height of the scanning angle in the vertical direction is greater than the geometric factor b .

[0062] Specifically, when the tilt angle is increased, and the scanning range of the scanning device 4 still does not exceed the value of the geometric factor, the tilt angle is further increased to continue to obtain the atmospheric concentration data of the remaining geometric factor overlapping areas, until the atmospheric concentration data in all geometric factor overlapping areas are obtained through tilt measurement. Then the acquired atmospheric concentration data replaces the atmospheric concentration data of the area obtained by vertical scanning. It is worth noting that if the atmospheric concentration data of the geometric factor overlapping area measured during the tilt measurement are repeated, the atmospheric concentration data obtained at the minimum tilt angle is taken to replace the atmospheric concentration data obtained by vertical scanning, because the smaller the tilt angle, although the scanning area in the vertical direction is smaller, the data is more accurate.

[0063] In another embodiment of the present invention, the scanning device 4 is set at different tilt angles to scan the atmospheric concentration data, and obtaining the oblique atmospheric data specifically includes the following steps:

[0064] According to mathematical formula sinC=b / L Obtain the maximum tilt angle of the scanning device 4 C ,in b Represents the value of the laser radar 3 geometry factor, L Indicates the effective detection distance of the scanning device 4 in the horizontal direction;

[0065] Take the minimum tilt angle α , at an inclination angle α~C Take several tilt angle values ​​within the range, among which the minimum tilt angle α Infinitely approaching 0;

[0066] The scanning device 4 is adjusted according to the tilt angle value and the maximum tilt angle. C The atmosphere is scanned multiple times to obtain multiple sets of slant atmospheric data.

[0067] Specifically, when the scanning device 4 is tilted at the maximum angle C When scanning, the atmospheric concentration data at the maximum height of the geometric factor overlap area can be obtained, but if only scanning at the maximum tilt angle is performed, it may not be possible to obtain completely accurate atmospheric concentration data at the lower height. Therefore, it is necessary to select several smaller tilt angles to continue scanning, and then find the complete atmospheric concentration parameters in the geometric factor overlap area from the tilt range atmospheric data obtained from several tilt scans.

[0068] Furthermore, the step of obtaining data in the laser radar blind area and the overlapping area of ​​the geometric factor from the oblique range atmospheric data to replace the data of the corresponding height in the vertical scanning atmospheric data specifically includes the following steps:

[0069] The data in the laser radar blind area and the overlapping area of ​​the geometric factor are obtained from multiple sets of slant-range atmospheric data to replace the data in the vertical scanning atmospheric data. If there is overlapping data in the multiple sets of slant-range atmospheric data in the overlapping area of ​​the radar blind area and the geometric factor during the replacement process, the data measured when the inclination angle is the smallest is used.

[0070] Furthermore, when the scanning device 4 performs tilted scanning, the spatial resolution of the scanning device 4 needs to be adjusted to the product of the spatial resolution during vertical scanning and the sine value of the tilt angle.

[0071] Specifically, in order to obtain more accurate data when the scanning device 4 is tilted, the spatial resolution needs to be adjusted before scanning. The spatial resolution is set to China ,in C The spatial resolution set by the scanning device 4 during vertical scanning.

[0072] like Figure 4-7 As shown, the method is used to measure the concentration of a certain component gas in the atmosphere, and the geometric factor overlap area is 500m , the effective detection distance in the horizontal direction is 2000m , the spatial resolution is 7.5m , the minimum pitch angle of the scanning device 4 is 2° .

[0073] (1) Scan vertically 2° The data corresponds to a vertical height of 17.45m~69.8m , the spatial resolution is 0.26m。

[0074] (2) Scan vertically 10° The data corresponds to a vertical height of 70.1m~346.43m, the spatial resolution is 1.3m.

[0075] (3) Scan vertically 20° The data corresponds to a vertical height of 348.84m~500m , the spatial resolution is 2.56m.

[0076] (4) Vertical detection data, corresponding to the vertical height 500m~2000m , the spatial resolution is 7.5m .

[0077] The gas concentration in the oblique direction is converted to the vertical concentration. By combining the four segments of data, the vertical concentration can be obtained. 17.45m~2000m of gas concentration.

[0078] exist Figure 7 In the figure, in the area below 500 meters in height, that is, in the area where the geometric factors overlap, the right side shows the gas concentration obtained by vertical measurement, and the left side shows the gas concentration obtained by multiple splicing of oblique scans. The difference between the two can be intuitively understood from the figure, and it can be seen that this method can effectively improve the detection accuracy of radar blind areas and geometric factor overlapping areas compared with traditional direct vertical detection.

[0079] like Figure 3 As shown, in another embodiment of the present invention, a detection device for the blind area and geometric overlap area of ​​an atmospheric laser radar is also disclosed.

[0080] The detection device includes a laser radar 3, a scanning device 4, and a computing unit;

[0081] The laser radar 3 is used to emit a laser beam into the atmosphere and receive radiation signals generated by the interaction between the laser beam and the atmosphere, and transmit the signals to the computing unit;

[0082] The scanning device 4 is used to change the transmission and reception directions;

[0083] The calculation unit is used to execute the method for detecting blind spots and geometric overlapping areas of atmospheric laser radar described in any one of the above embodiments.

[0084] In another embodiment of the present invention, a computer-readable storage medium is disclosed, on which a computer program is stored. When the computer program is run, a method for detecting blind spots and geometric overlapping areas of an atmospheric laser radar as described in any one of the above embodiments is executed.

[0085] In another embodiment of the present invention, a computer device includes a processor and a storage medium, on which a computer program is stored. The processor reads and runs the computer program from the storage medium to execute a method for detecting blind spots and geometric overlapping areas of an atmospheric lidar as described in any one of the above embodiments.

[0086] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for detecting blind areas and geometric overlapping areas of atmospheric lidar, It is characterized in that The detection method comprises the following steps: The scanning device is set vertically on the ground to scan the atmospheric concentration data to obtain vertical scanning atmospheric data; The scanning device is set at different tilt angles to scan the atmospheric concentration data and obtain the oblique atmospheric data; Obtain data in the laser radar blind area and the overlapping area of ​​the geometric factor from the slant range atmospheric data to replace the data of the corresponding height in the vertical scanning atmospheric data; The scanning device is set at different tilt angles to scan the atmospheric concentration data, and obtaining the oblique atmospheric data specifically includes the following steps: Obtain the geometric factor b and horizontal effective detection distance L of the laser radar; Set the value of the scanning device pitch angle to α , scan the near-ground atmosphere and obtain slant atmospheric data. At this time, the effective detection height in the vertical direction is Lsinα , geometric factor bsinα ; The method of obtaining data in the laser radar blind area and the overlapping area of ​​the geometric factor from the oblique range atmospheric data to replace the data of the corresponding height in the vertical scanning atmospheric data specifically comprises the following steps: like Lsinα The value is not less than the geometric factor b, the scan is completed, and the vertical height range is bsinα~b In the area, the results of this scan will replace the atmospheric concentration data of the corresponding height obtained by vertical scanning; like Lsinα The value is less than the geometric factor b， Continue with the tilt scan.

2. According to claim 1, a method for detecting blind areas and geometric overlapping areas of an atmospheric laser radar, It is characterized in that If Lsinα The value is less than the geometric factor b， Continuing the tilt scan specifically includes the following steps: like Lsinα The value is less than the geometric factor b , increase the pitch angle of the scanning device, denoted as β, where β>α; Rescan, get β Slant atmospheric concentration data at angles; In vertical height range bsinα~Lsinα In the area, the atmospheric concentration data of the corresponding height obtained by vertical scanning is replaced by the last scanning data; In vertical height range Lsinα~Lsinβ In the area, the scan result will replace the atmospheric concentration data of the corresponding height obtained by vertical scanning.

3. The method for detecting blind areas and geometric overlapping areas of an atmospheric laser radar according to claim 2, It is characterized in that In the vertical height range Lsinα~Lsinβ In the area, after replacing the atmospheric concentration data of the corresponding height obtained by vertical scanning with the scanning result, the following steps are also included: Compare Lsinβ and b The numerical value of like Lsinβ≥b , the scan is complete; if Lsinβ<b , the pitch angle of the scanning device is continued to be increased to scan the atmospheric concentration data, and the atmospheric concentration data of the radar blind area and the geometric factor overlapping area that have not been replaced are replaced until the effective detection height of the scanning angle in the vertical direction is greater than the geometric factor b .

4. The method for detecting blind areas and geometric overlapping areas of atmospheric laser radar according to claim 1, It is characterized in that The scanning device is set at different tilt angles to scan the atmospheric concentration data, and obtaining the oblique atmospheric data specifically includes the following steps: According to mathematical formula sinC=b / L Find the maximum tilt angle of the scanning device C ,in b represents the value of the laser radar geometry factor, L Indicates the effective detection distance of the scanning device in the horizontal direction; Take the minimum tilt angle α , at an inclination angle α~C Take several tilt angle values ​​within the range, among which the minimum tilt angle α Infinitely approaching 0; Adjust the scanning device according to the tilt angle value and the maximum tilt angle. C The atmosphere is scanned multiple times to obtain multiple sets of slant atmospheric data.

5. The method for detecting blind areas and geometric overlapping areas of atmospheric laser radar according to claim 4, It is characterized in that The method of obtaining data in the laser radar blind area and the overlapping area of ​​the geometric factor from the oblique range atmospheric data to replace the data of the corresponding height in the vertical scanning atmospheric data specifically comprises the following steps: The data in the laser radar blind area and the overlapping area of ​​the geometric factor are obtained from multiple sets of slant-range atmospheric data to replace the data in the vertical scanning atmospheric data. If there is overlapping data in the multiple sets of slant-range atmospheric data in the overlapping area of ​​the radar blind area and the geometric factor during the replacement process, the data measured when the inclination angle is the smallest is used.

6. The method for detecting blind areas and geometric overlapping areas of an atmospheric laser radar according to any one of claims 1 to 4, It is characterized in that When the scanning device performs tilted scanning, the spatial resolution of the scanning device needs to be adjusted to the product of the spatial resolution during vertical scanning and the sine value of the tilt angle.

7. A detection device for blind areas and geometric overlapping areas of atmospheric laser radar, It is characterized in that The detection device includes a laser radar, a scanning device, and a computing unit; The laser radar is used to emit a laser beam into the atmosphere and receive radiation signals generated by the interaction between the laser beam and the atmosphere, and transmit the signals to the computing unit; The scanning device is used to change the transmission and reception directions; The computing unit is used to execute the method for detecting blind spots and geometric overlapping areas of an atmospheric laser radar as described in any one of claims 1 to 6.

8. A computer-readable storage medium, It is characterized in that A computer program is stored on the medium, and after the computer program is run, a method for detecting blind areas and geometric overlapping areas of an atmospheric laser radar as described in any one of claims 1 to 6 is executed.

9. A computer device, It is characterized in that It includes a processor and a storage medium, wherein a computer program is stored on the storage medium, and the processor reads and runs the computer program from the storage medium to execute a method for detecting blind spots and geometric overlapping areas of an atmospheric laser radar as described in any one of claims 1 to 6.

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