A laser radar with automatic centering device and centering method thereof

Abstract

A laser radar with a centering device is provided, comprising a transmitting laser, a receiving telescope, and a light detector. The laser radar has a first adjustment direction for adjusting the centering deviation of the transmitted laser and a second adjustment direction perpendicular to the first adjustment direction. The laser radar is characterized in that it also includes a light shielding plate, the light shielding plate including at least one light-transmitting unit, the light shielding plate being arranged at the echo light entrance of the telescope and being used to spatially modulate the echo light so that on the light-transmitting surface of the echo light entrance of the telescope, only a light-transmitting area in a specific orientation transmits light to reach the light detector at a specific time. By comparing the size and shape of the echo signals of two light-transmitting areas with a geometrically symmetrical relationship in the first adjustment direction and / or the second adjustment direction, the size and direction of the centering deviation in the corresponding adjustment direction can be determined, thereby performing centering adjustment in the corresponding adjustment direction of the laser radar.

Description

Technical Field

[0001] The invention relates to a laser radar with an automatic centering device and a centering method thereof. Background Art

[0002] LiDAR alignment involves both detection and adjustment. Current technologies offer both manual and automatic alignment methods.

[0003] Manual adjustment involves adjusting the angle between the laser beam and the optical axis of the receiving telescope, then measuring the corresponding changes in the amplitude and shape of the echo signal profile as the angle changes in both directions. The lidar's alignment affects both the amplitude and shape of the echo signal. Optimal alignment ensures that the laser beam remains within the receiving telescope's field of view throughout the lidar's detection range. This prioritizes receiving long-range signals, rather than focusing on maximum amplitude for close-range signals. Therefore, determining system alignment and adjusting alignment generally requires expertise with actual lidar operating experience.

[0004] A commonly used automatic LiDAR centering algorithm adjusts the laser beam's direction and scans dozens of points at two perpendicular angles. The maximum value of the signal at different distances is calculated to achieve the two optimal centering angles. To maintain a sufficient signal-to-noise ratio, data acquisition for each point takes tens of seconds to a minute, and the entire scan can take up to ten minutes. Reliable centering results require a stable atmosphere throughout the entire scan time. This automatic centering algorithm is time-consuming, requires high atmospheric stability, and has a low success rate. While it can achieve automatic centering adjustments, it is not suitable for rapid detection of centering status. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a laser radar with a centering device, the laser radar includes a transmitting laser, a receiving telescope, and a light detector, and the laser radar includes a first adjustment direction for adjusting the centering deviation of the transmitted laser and a second adjustment direction perpendicular to the first adjustment direction. It is characterized in that the laser radar also includes a shading device, the shading device includes a shading plate, the shading plate has at least one light-transmitting unit, which is arranged at the echo light entrance of the telescope and is used to spatially modulate the echo light so that on the light-transmitting surface of the echo light entrance of the telescope, only one light-transmitting area can transmit light to reach the light detector within a specific time. By comparing the size and shape of the echo signals of two light-transmitting areas with a geometrically symmetrical relationship arranged along the first adjustment direction, and / or comparing the size and shape of the echo signals of two light-transmitting areas with a geometrically symmetrical relationship arranged along the second adjustment direction, the size and direction of the centering deviation in the corresponding adjustment direction can be detected, thereby performing centering adjustment in the corresponding adjustment direction of the laser radar.

[0006] Preferably, the specific light-transmitting area is configured as follows:

[0007] In a Cartesian coordinate system having a first coordinate axis (x) and a second coordinate axis (y), the coordinate axes (x, y) divide the entrance light-transmitting surface into four equal parts.

[0008] Wherein, the first coordinate axis (x) is parallel to the first adjustment direction, and the second coordinate axis (y) is parallel to the second adjustment direction.

[0009] The light-transmitting area includes a first light-transmitting area and a second light-transmitting area, the first light-transmitting area is arranged in the first quadrant and the fourth quadrant, and the second light-transmitting area is arranged in the second quadrant and the third quadrant, or the first light-transmitting area is arranged in the second quadrant and the third quadrant, and the second light-transmitting area is arranged in the first quadrant and the fourth quadrant,

[0010] The first light-transmitting area and the second light-transmitting area are symmetrical about the second coordinate axis (y).

[0011] The first light-transmitting area has two states: light-transmitting and light-shielding; the second light-transmitting area has two states: light-transmitting and light-shielding.

[0012] Preferably, the specific light-transmitting area includes a third light-transmitting area and a fourth light-transmitting area, the third light-transmitting area is arranged in the first quadrant and the second quadrant, and the fourth light-transmitting area is arranged in the fourth quadrant and the third quadrant, or the third light-transmitting area is arranged in the fourth quadrant and the third quadrant, and the fourth light-transmitting area is arranged in the first quadrant and the second quadrant.

[0013] The third light-transmitting area and the fourth light-transmitting area are symmetrical about the first coordinate axis (x).

[0014] The third light-transmitting area has two states: light-transmitting and light-blocking; and the fourth light-transmitting area has two states: light-transmitting and light-blocking.

[0015] Preferably, the first light-transmitting area and the second light-transmitting area are symmetrical about the first coordinate axis (x).

[0016] Preferably, the third light-transmitting area and the fourth light-transmitting area are symmetrical about the second coordinate axis (y).

[0017] Preferably, the first light-transmitting area and the second light-transmitting area have a sector-shaped vertex angle ranging from 90 degrees to 180 degrees with the coordinate origin as the vertex.

[0018] Preferably, the third light-transmitting area and the fourth light-transmitting area are fan-shaped, and the vertex angle of the fan-shaped area with the coordinate origin as the vertex ranges from 90 degrees to 180 degrees.

[0019] In addition, if the detection signal of the first light-transmitting area is consistent with the detection signal of the second light-transmitting area, the laser radar is centered in the first adjustment direction, or if the detection signal of the first light-transmitting area is consistent with the detection signal of the second light-transmitting area at the far end, the laser radar is centered in the first adjustment direction.

[0020] In addition, if the detection signal of the third light-transmitting area is consistent with the detection signal of the fourth light-transmitting area, the laser radar is centered in the second adjustment direction, or if the detection signal of the third light-transmitting area is consistent with the detection signal of the fourth light-transmitting area at the far end, the laser radar is centered in the second adjustment direction.

[0021] Preferably, if the detection signal of the first light-transmitting area is consistent with the detection signal of the second light-transmitting area, the laser radar is centered in the first adjustment direction.

[0022] Preferably, if the detection signal of the third light transmission area is consistent with the detection signal of the fourth light transmission area, the laser radar is centered in the second adjustment direction.

[0023] Preferably, the fan-shaped vertex angle of the first light-transmitting area, the second light-transmitting area, the third light-transmitting area and the fourth light-transmitting area) is 90 degrees, and the light-shielding plate includes a first unit (W), a second unit (E), a third unit (N) and a fourth unit (S), each unit can be opened and closed independently to allow light to pass and block light. When in use, the light-shielding plate is fixed on the echo light entrance of the telescope, and the first unit (W), the second unit (E), the third unit (N) and the fourth unit (S) correspond to the first light-transmitting area, the second light-transmitting area, the third light-transmitting area and the fourth light-transmitting area respectively.

[0024] Preferably, the fan-shaped vertex angles of the first light-transmitting area, the second light-transmitting area, the third light-transmitting area and the fourth light-transmitting area are 180 degrees, and the light-shielding plate includes a first unit (A), a second unit (B), a third unit (C) and a fourth unit (D), each unit can be opened and closed independently to allow light to pass and block light. When in use, the light-shielding plate is fixed on the echo light entrance of the telescope, the first unit (A) and the third unit (C) can be opened or closed at the same time and correspond to the first light-transmitting area, the second unit (B) and the fourth unit (D) can be opened or closed at the same time and correspond to the second light-transmitting area, the first unit (A) and the second unit (B) can be opened or closed at the same time and correspond to the third light-transmitting area, and the third unit (C) and the fourth unit (D) can be opened or closed at the same time and correspond to the fourth light-transmitting area.

[0025] Preferably, the light-shielding plate includes a fan-shaped light-transmitting unit that can transmit light and corresponds to the shape of the light-transmitting area, and the other parts are light-shielding. When in use, it is installed on the echo light entrance and rotates. When the light-transmitting unit coincides with the first light-transmitting area, the light detector can detect the echo signal from the first light-transmitting area; when the light-transmitting unit coincides with the second light-transmitting area, the light detector can detect the echo signal from the second light-transmitting area; when the light-transmitting unit coincides with the third light-transmitting area, the light detector can detect the echo signal from the third light-transmitting area; when the light-transmitting unit coincides with the fourth light-transmitting area, the light detector can detect the echo signal from the fourth light-transmitting area.

[0026] Preferably, the light shielding plate includes a fan-shaped light-transmitting unit corresponding to the shape of the light-transmitting area and capable of transmitting light, and the vertex angle of the fan-shaped unit is 90 degrees or 180 degrees.

[0027] On the other hand, the present invention provides a method for detecting and adjusting the centering of a laser radar, wherein the laser radar includes a transmitting laser, a receiving telescope, and a light detector, and the laser radar includes a first adjustment direction for adjusting the centering deviation of the transmitting laser and a second adjustment direction perpendicular to the first adjustment direction. The method is characterized in that a shading device is provided, wherein the shading device includes a shading plate, which has at least one light-transmitting unit, which is arranged at the echo light entrance of the telescope and is used to spatially modulate the echo light so that on the light-transmitting surface of the echo light entrance of the telescope, only one light-transmitting area can transmit light to reach the light detector within a specific time. By comparing the size and shape of the echo signals of two light-transmitting areas with a geometrically symmetrical relationship arranged along the first adjustment direction, and / or comparing the size and shape of the echo signals of two light-transmitting areas with a geometrically symmetrical relationship arranged along the second adjustment direction, the size and direction of the centering deviation in the corresponding adjustment direction can be detected, thereby performing centering adjustment in the corresponding adjustment direction of the laser radar.

[0028] Preferably, the specific light-transmitting area is configured as follows:

[0029] In a Cartesian coordinate system having a first coordinate axis (x) and a second coordinate axis (y), the coordinate axes (x, y) divide the entrance light-transmitting surface into four equal parts.

[0030] Wherein, the first coordinate axis (x) is parallel to the first adjustment direction, and the second coordinate axis (y) is parallel to the second adjustment direction.

[0031] The light-transmitting area includes a first light-transmitting area and a second light-transmitting area, the first light-transmitting area is arranged in the first quadrant and the fourth quadrant, and the second light-transmitting area is arranged in the second quadrant and the third quadrant, or the first light-transmitting area is arranged in the second quadrant and the third quadrant, and the second light-transmitting area is arranged in the first quadrant and the fourth quadrant,

[0032] The first light-transmitting area and the second light-transmitting area are symmetrical about the second coordinate axis (y).

[0033] The first light-transmitting area has two states: light-transmitting and light-blocking; the second light-transmitting area has two states: light-transmitting and light-blocking.

[0034] Preferably, the third light-transmitting area and the fourth light-transmitting area are further included, the third light-transmitting area is arranged in the first quadrant and the second quadrant, and the fourth light-transmitting area is arranged in the fourth quadrant and the third quadrant, or the third light-transmitting area is arranged in the fourth quadrant and the third quadrant, and the fourth light-transmitting area is arranged in the first quadrant and the second quadrant.

[0035] The third light-transmitting area and the fourth light-transmitting area are symmetrical about the first coordinate axis (x).

[0036] The third light-transmitting area has two states: light-transmitting and light-blocking; and the fourth light-transmitting area has two states: light-transmitting and light-blocking.

[0037] Additionally, when measuring and adjusting the centering deviation in the first adjustment direction, the method includes:

[0038] Step 1: The first light-transmitting area is light-transmitted, the second light-transmitting area is shielded, and the light detector detects the first light signal from the first light-transmitting area;

[0039] Step 2: The second light-transmitting area is allowed to pass light, the first light-transmitting area is shielded from light, and the light detector detects a second signal from the second light-transmitting area;

[0040] Step 3: Compare the first optical signal and the second optical signal. If the two are consistent, it means that the laser radar is well aligned in the first adjustment direction of the laser emission corresponding to the second light-transmitting area and the third light-transmitting area, and the measurement is completed.

[0041] If the two are inconsistent, performing centering adjustment in the first adjustment direction of the laser emission according to the deviation between the first signal and the second signal;

[0042] Repeat the above steps until the first optical signal and the second optical signal are consistent.

[0043] In addition, when measuring and adjusting the centering deviation in the second adjustment direction, the method includes the following steps:

[0044] Step 4: light is transmitted to the third light-transmitting area, and light is shielded from the first light-transmitting area, the second light-transmitting area, and the fourth light-transmitting area. The light detector detects a third light signal from the third light-transmitting area.

[0045] Step 5: The fourth light-transmitting area is allowed to pass light, the first light-transmitting area, the second light-transmitting area, and the third light-transmitting area are shielded from light, and the light detector detects a fourth light signal from the fourth light-transmitting area;

[0046] Step 6: Compare the third light signal and the fourth light signal. If they are consistent, it means that the laser radar is well aligned in the second adjustment direction corresponding to the third light transmission area and the fourth area. The measurement is completed.

[0047] If the two are inconsistent, performing centering adjustment in the second adjustment direction of the laser emission according to the deviation between the third signal and the fourth signal;

[0048] Repeat the above steps until the third optical signal and the fourth optical signal are consistent.

[0049] In addition, the first light-transmitting area and the second light-transmitting area are symmetrical about the first coordinate axis (x).

[0050] In addition, the third light-transmitting area and the fourth light-transmitting area are symmetrical about the first coordinate axis (x).

[0051] In addition, between step 2 and step 3, the following steps are also included:

[0052] The first light-transmitting area allows light to pass through, the second light-transmitting area blocks light, and the light detector measures a first light signal from the first area;

[0053] Compare the two first optical signals before and after. If they are consistent, proceed to step 3. If they are inconsistent, return to step 1.

[0054] In addition, between step 4 and step 5, the following steps are also included:

[0055] The third light-transmitting area allows light to pass through, the first light-transmitting area, the second light-transmitting area, and the fourth light-transmitting area are shielded from light, and a third optical signal from the third light-transmitting area is measured;

[0056] Compare the third optical signals before and after twice. If they are consistent, proceed to step 6. If they are inconsistent, return to step 4.

[0057] In addition, the first light-transmitting area and the second light-transmitting area are fan-shaped, and the vertex angle of the fan-shaped area with the coordinate origin as the vertex ranges from 90 degrees to 180 degrees.

[0058] In addition, the third light-transmitting area and the fourth light-transmitting area are fan-shaped, and the vertex angle of the fan-shaped area with the coordinate origin as the vertex ranges from 90 degrees to 180 degrees.

[0059] In addition, the fan-shaped vertex angles of the first light-transmitting area, the second light-transmitting area, the third light-transmitting area and the fourth light-transmitting area are 90 degrees, and the light-shielding plate includes a first unit (W), a second unit (E), a third unit (N) and a fourth unit (S), each of which can be opened and closed independently to allow light to pass through and block light. When in use, the light-shielding plate is fixed on the echo light entrance of the telescope, and the first unit (W), the second unit (E), the third unit (N) and the fourth unit (S) correspond to the first light-transmitting area, the second light-transmitting area, the third light-transmitting area and the fourth light-transmitting area respectively.

[0060] In addition, the fan-shaped vertex angles of the first light-transmitting area, the second light-transmitting area, the third light-transmitting area and the fourth light-transmitting area are 180 degrees, and the light-shielding plate includes a first unit (A), a second unit (B), a third unit (C) and a fourth unit (D), each unit can be opened and closed independently to allow light to pass and block light. When in use, the light-shielding plate is fixed on the echo light entrance of the telescope, and the first unit (A) and the third unit (C) can be opened or closed at the same time and correspond to the first light-transmitting area, the second unit (B) and the fourth unit (D) can be opened or closed at the same time and correspond to the second light-transmitting area, the first unit (A) and the second unit (B) can be opened or closed at the same time and correspond to the third light-transmitting area, and the third unit (C) and the fourth unit (D) can be opened or closed at the same time and correspond to the fourth light-transmitting area.

[0061] In addition, the light-shielding plate includes a fan-shaped light-transmitting unit that can transmit light and corresponds to the shape of the light-transmitting area, and the other parts are light-shielding. When in use, it is installed on the echo light entrance and rotated. When the light-transmitting unit coincides with the first light-transmitting area, the light detector can detect the echo signal from the first light-transmitting area; when the light-transmitting unit coincides with the second light-transmitting area, the light detector can detect the echo signal from the second light-transmitting area; when the light-transmitting unit coincides with the third light-transmitting area, the light detector can detect the echo signal from the third light-transmitting area; when the light-transmitting unit coincides with the fourth light-transmitting area, the light detector can detect the echo signal from the fourth light-transmitting area.

[0062] In addition, the light shielding plate includes a fan-shaped light-transmitting unit corresponding to the shape of the light-transmitting area and capable of transmitting light, and the vertex angle of the fan-shaped unit is 90 degrees or 180 degrees.

[0063] Beneficial effects of the present invention:

[0064] (1) Automatically detect the optical alignment status of the LiDAR system and automatically correct alignment deviations without the involvement of professional technicians, thereby improving alignment accuracy and reducing alignment time. Compared with existing LiDAR automatic alignment algorithms, the requirements for atmospheric stability during alignment detection are greatly reduced, thereby improving the success rate of automatic alignment.

[0065] (2) The optical telescope is divided into four equal quadrants and four shading units are provided. According to the geometric symmetry relationship, if the laser radar is in a completely centered state, the symmetrical shading plates are opened respectively, and the laser radar signals obtained should be equal. On the contrary, if the signals are inconsistent, it can be known that the optical system is not centered, and the direction and size of the laser beam pointing deviation can be judged from the difference between the two signals. Since only two signals need to be compared, the requirements for atmospheric stability are lower than the scanning centering algorithm of the existing technology (which requires comparison of about 10 signals), the centering success rate is higher, the centering accuracy is higher, and the time required is shorter. Compared with manual centering, automatic centering can be unmanned. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figures 1A to 1M is an embodiment of various light-passing areas for spatial modulation by the shading device according to the present invention;

[0067] Figure 2a-2c is a schematic diagram of light centering and non-centering of a coaxial laser radar with a light shielding device according to the present invention;

[0068] Figure 3a 、 3b is a schematic diagram of an embodiment of an array-type light shielding plate with light-transmitting units according to the present invention;

[0069] Figure 4a 、 Figure 4b is a schematic diagram of an embodiment of a rotary light shielding plate with a light-transmitting unit according to the present invention;

[0070] Figure 5 is a schematic diagram of the geometric relationship between centered and non-centered light rays according to the present invention;

[0071] Figure 6 is a flowchart of centering detection and centering adjustment according to one embodiment of the present invention;

[0072] Figure 7 is a schematic diagram of light centering and non-centering of a non-coaxial laser radar with a light shielding device according to the present invention;

[0073] Figure 8a is a schematic diagram of a functional block of a coaxial laser radar with a light shielding device according to an embodiment of the present invention;

[0074] Figure 8b2. Schematic diagram of a non-coaxial laser radar functional block with a shading device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0075] The present invention provides a centering method and device for a laser radar. The laser radar includes a transmitting laser, a receiving telescope, and a light detector, and the laser radar includes a first adjustment direction for adjusting the centering deviation of the transmitting laser and a second adjustment direction perpendicular to the first adjustment direction, wherein the laser radar also includes a shading device, and the shading device includes a shading plate, which is arranged at the echo light entrance of the telescope and is used to spatially modulate the echo light, so that on the light-transmitting surface of the echo light entrance of the telescope, only a specific light-transmitting area can transmit light to reach the light detector at a specific time. Figure 1A As shown. The specific light-transmitting area is configured as follows: the entrance light-transmitting surface is divided into four equal parts in a Cartesian coordinate system, each part corresponding to a quadrant. The coordinate system has a horizontal axis x and a vertical axis y. For the convenience of discussion, the quadrants are defined as follows: the first quadrant is located above the x-axis and to the right of the y-axis, the second quadrant is located above the x-axis and to the left of the y-axis; the third quadrant is located below the x-axis and to the left of the y-axis, and the fourth quadrant is located below the x-axis and to the right of the y-axis. In this way, the first and second quadrants are symmetrical with the fourth and third quadrants about the x-axis, and the first and fourth quadrants are symmetrical with the second and third quadrants about the y-axis.

[0076] The x-axis is parallel to the first adjustment direction, and the y-axis is parallel to the second adjustment direction.

[0077] In order to measure and adjust the centering deviation in the first adjustment direction, the first light-transmitting area 11 is set in the second quadrant and the third quadrant, and the second light-transmitting area 12 is set in the first quadrant and the fourth quadrant. Of course, the second light-transmitting area 12 can also be set in the second quadrant and the third quadrant, while the first light-transmitting area 11 is set in the first quadrant and the fourth quadrant.

[0078] The first light-transmitting area 11 and the second light-transmitting area 12 are symmetrical about the second coordinate axis (y).

[0079] Preferably, the first light-transmitting area 11 and the second light-transmitting area 12 are symmetrical about the x-axis.

[0080] The first light-transmitting area 11 has two states: light-transmitting and light-shielding; and the second light-transmitting area 12 has two states: light-transmitting and light-shielding.

[0081] To measure and adjust centering deviation in the second adjustment direction, the specific light-transmitting area further includes a third light-transmitting area 13 and a fourth light-transmitting area 14. The third light-transmitting area is disposed within the first and second quadrants, and the fourth light-transmitting area is disposed within the fourth and third quadrants. Of course, the reverse arrangement may also be employed, with the third light-transmitting area 13 disposed within the fourth and third quadrants, and the fourth light-transmitting area 14 disposed within the first and second quadrants.

[0082] The third light-transmitting area 13 and the fourth light-transmitting area 14 are symmetrical about the x-axis.

[0083] Preferably, the third light-transmitting area 13 and the fourth light-transmitting area 14 are symmetrical about the second coordinate axis (y).

[0084] The third light-transmitting area has two states: light-transmitting and light-blocking; and the fourth light-transmitting area has two states: light-transmitting and light-blocking.

[0085] The following combination Figure 1B-1I The present invention is described separately.

[0086] Figure 1B This is the modulation pattern of the telescope echo entrance's light-transmitting surface at the first measurement interval as seen from the light detector. In the first measurement interval, only the first light-transmitting area 11 transmits light, while other areas are shielded from light.

[0087] Figure 1C The figure shows the modulation pattern of the light-transmitting surface of the telescope echo entrance in the second measurement interval as seen from the perspective of the light detector. In the second measurement interval, only the second light-transmitting area 12 is light-transmitting, and the other areas are shielded from light.

[0088] Figure 1D The modulation pattern of the light-transmitting surface of the telescope echo entrance seen from the perspective of the light detector in the third measurement interval is shown. In the third measurement interval, only the third light-transmitting area 13 is light-transmitting, and the other areas are shielded from light.

[0089] Figure 1E The modulation pattern of the light-transmitting surface of the telescope echo entrance seen from the perspective of the light detector in the fourth measurement interval is shown. In the fourth measurement interval, only the fourth light-transmitting area 14 transmits light, and the other areas are shielded from light.

[0090] Those skilled in the art will readily understand that in the above-mentioned embodiment, the shape of the light-transmitting area is circular. However, this is not limited to a circle and can be any other shape. Each light-transmitting area is not limited to being enclosed by a continuous closed curve and can also be multiple discrete areas. As long as they meet the definition of a light-transmitting area, they can function as a light-transmitting area. To improve the detection signal-to-noise ratio, the area of ​​each light-transmitting area should be as large as possible.

[0091] Figure 1F-1IAnother embodiment of the light-transmitting area is provided. Here, the first light-transmitting area 11, the second light-transmitting area 12, the third light-transmitting area 13, and the fourth light-transmitting area 14 are shaped like a sector, with the angles between the rays of the sector and the coordinate axis being plus or minus 45 degrees. In other words, in this embodiment, the light-transmitting area is shaped like a quarter circle.

[0092] refer to Figure 1J-1M In another embodiment, the first light-transmitting area 11, the second light-transmitting area 12, the third light-transmitting area 13 and the fourth light-transmitting area 14 are in the shape of a semicircle, that is, the first light-transmitting area 11, the second light-transmitting area 12, the third light-transmitting area 13 and the fourth light-transmitting area 14 occupy the second-third quadrant, the first-fourth quadrant, the first-second quadrant and the third-fourth quadrant respectively.

[0093] The above quarter-circle or half-circle light-passing area settings all reflect the consideration of making the light-passing area as large as possible, and of course the crosstalk problem must also be considered.

[0094] See Figure 2a . A coaxial laser radar is shown, comprising a laser 21, a light detector 22 and a receiving telescope 23. The laser radar emits a laser beam 28 coaxial with the receiving telescope 23. A shading device is provided outside the echo entrance of the receiving telescope, and the shading device comprises a shading plate 24. The function of the shading plate 24 is to spatially modulate the echo, so as to provide a plurality of spatially distributed light-transmitting areas on the light-transmitting surface of the echo entrance of the telescope, each light-transmitting area having two states of light-transmitting and light-shielding. The light detector detects the echoes from specific light-transmitting areas on the light-transmitting surface in a time-sharing manner, that is, light signals from different specific areas are measured at different time intervals. By comparing the size and shape of the detection signals of different specific areas, the size and direction of the centering deviation are determined, so as to perform centering adjustment in the first direction of the laser radar and in the second direction perpendicular to the first direction.

[0095] Specifically, Figure 2a The diagram shows a well-aligned laser beam and telescope. When in good alignment, the optical signals measured in the first and second light-transmitting areas are consistent, and the optical signals measured in the third and fourth light-transmitting areas are consistent. Preferably, the optical signals measured in the first, second, third, and fourth light-transmitting areas are consistent.

[0096] Figure 2c The figure shows the laser beam 29 deviating from the optical axis of the telescope, i.e., not centered, corresponding to Figure 2b Numbers 25 and 27.

[0097] Figure 2b See the following combination for explanation Figure 5 Discussion.

[0098] See Figure 3a . Figure 3a This is an embodiment of a light shield. The light shield can modulate the light corresponding to the above Figure 1F-1I The pattern of the light-transmitting area shown is a quarter circle. In this embodiment, the shading plate 2 includes four shading units, namely the first unit W, the second unit N, the third unit E and the fourth unit S. When W, N, E and S each correspond to a quadrant for operation, the shading plate is fixed on the light entrance, and each unit corresponds to a light-transmitting area on the light-transmitting surface. For example, W corresponds to the first light-transmitting area, E corresponds to the second light-transmitting area, N corresponds to the third light-transmitting area, and S corresponds to the fourth light-transmitting area. Each shading unit can be opened or closed independently. When a shading unit is opened, light will be allowed to pass through the quadrant into the telescope, and when the shading unit is closed, light will not be allowed to pass through the shading unit into the telescope. When the laser radar is in a good alignment state, that is, when the laser beam is parallel to and coincides with the optical axis of the telescope, the four signal profiles when the shading plates of one of the quadrants are opened should be completely consistent, otherwise it means that the alignment state of the laser radar is not good.

[0099] In this embodiment, the shading plate also includes a light-transmitting circular hole at the center position corresponding to the telescope. If the laser beam is emitted from the bottom of the shading plate, the laser beam can be emitted into the air through the circular hole. The diameter of the circular hole should be equivalent to the diameter of the laser emission reflector. Of course, the shading plate is set below the laser beam emission mirror, that is, if the laser beam is emitted from the top of the shading plate, the circular hole can also be omitted; or when the laser radar is set off-axis, there can be no central circular hole (see Figure 8b ).

[0100] Usually, the adjustment of the laser emission angle needs to be adjusted in two mutually perpendicular directions. For example, Figure 3a In the figure, we assume that the two adjustment directions of the laser angle are the first adjustment direction along the left and right sides of the paper and the second adjustment direction perpendicular to the first adjustment direction along the top and bottom sides. Under this assumption, in this embodiment, the orientation of each unit of the light shielding plate corresponds to the orientation of each light-transmitting area on the corresponding light-transmitting surface. In this example, the quadrant axis of the light shielding plate is rotated 45 degrees relative to the first adjustment direction and the second adjustment direction. Figure 2a Thus, the unit WE corresponds to the adjustment in the first adjustment direction, and the unit NS corresponds to the adjustment in the second adjustment direction.

[0101] The advantage of this layout is that it can minimize the coupling between the two directions, and can judge the size and direction of the deviation in the two directions separately, so as to achieve independent adjustment in the two directions.

[0102] like Figure 3b, shows another embodiment of the light shield according to the present invention. The structure of this light shield is exactly the same as the previous embodiment, and it also adopts a four-quadrant light shield layout. However, when in use, the axes of the four quadrants coincide with the first adjustment direction and the second adjustment direction of the laser adjustment angle respectively. From the symmetry of the figure, it can be seen that Figure 3a and Figure 3b The equivalence of the adjustment direction is: W->A+C; E->B+D; N->A+B; S->C+D. That is, the shading plate can produce the aforementioned Figure 1J to Figure 1M The shapes of the first light-transmitting area 11 , the second light-transmitting area 12 , the third light-transmitting area 13 and the fourth light-transmitting area 14 are semicircular.

[0103] Figure 3b The advantage of this layout is that the signal-to-noise ratio is better because the shutters in two quadrants are opened at the same time. However, because both shutters are opened at the same time, the signals during each detection are not completely independent.

[0104] It will be understood by those skilled in the art that the above Figure 3a 、 Figure 3b The structure of the light shielding plate is only an embodiment and other variations are possible.

[0105] For example, for the aforementioned Figure 1F-1I The quarter circle light area setting shown can be used Figure 4a The sunshade setting can be used as Figure 3a An alternative embodiment. It can be a circular disk, where 41 represents a quarter-circle light-transmitting unit, and the rest of the unit is opaque. When in use, the light shield is placed on the echo entrance and rotates. When the light-transmitting unit coincides with the first light-transmitting area, the detector can detect the echo from the first light-transmitting area on the light-transmitting surface. When the light-transmitting unit coincides with the second light-transmitting area, the detector can detect the echo from the second light-transmitting area on the light-transmitting surface. When the light-transmitting unit coincides with the third light-transmitting area, the detector can detect the echo from the third light-transmitting area on the light-transmitting surface. When the light-transmitting unit coincides with the fourth light-transmitting area, the detector detects the echo from the fourth light-transmitting area on the light-transmitting surface.

[0106] The light shield above adopts a quarter-circle area light-transmitting unit, which can trigger the time-sharing measurement of the light signals in different light-transmitting areas on the light-transmitting surface by rotating.

[0107] See Figure 4b , as Figure 3bIn an alternative embodiment, the light shielding plate can be a circular disk, wherein 41 represents a light-transmitting unit, which is a semicircle in this embodiment, and the other semicircle does not transmit light. When in use, the light shielding plate is set on the echo entrance and rotates. When the light-transmitting unit coincides with the first light-transmitting area, the detector can detect the echo from the first light-transmitting area on the light-transmitting surface. When the light-transmitting unit coincides with the second light-transmitting area, the detector can detect the echo from the second light-transmitting area on the light-transmitting surface. When the light-transmitting unit coincides with the third light-transmitting area, the detector can detect the echo from the third light-transmitting area on the light-transmitting surface. When the light-transmitting unit coincides with the fourth light-transmitting area, the detector detects the echo from the fourth light-transmitting area on the light-transmitting surface. The light shielding plate can produce the aforementioned Figure 1J to Figure 1M The shapes of the first light-transmitting area 11 , the second light-transmitting area 12 , the third light-transmitting area 13 and the fourth light-transmitting area 14 are semicircular.

[0108] Although the layouts of the light-transmitting areas on the different light-transmitting surfaces or the layouts of the light-shielding units of the light-shielding plates are different, the principles and steps of the detection and adjustment process are the same.

[0109] refer to Figure 5 . The following uses Figure 3a The measurement and alignment principle of the present invention is explained by taking the shading plate of the laser radar as an example. When the laser radar is completely aligned, the four signals when the four units are turned on should be completely consistent. This is because the laser beam is in the h O Entering four sub-fields of view at the same height. According to the geometric relationship in the figure, we can get:

[0110]

[0111] Where r is the larger radius of the laser reflector or the telescope's secondary mirror, and FOV is the telescope's field of view, which is the same for each quadrant:

[0112] FOV=FOV W =FOV E =FOV N =FOV S

[0113] If the signals of the four units are different, the symmetrical geometric relationship is used to determine the direction and magnitude of the deviation of the laser radar alignment based on their differences. Assume that the direction of the laser beam on the paper is deviated to the left (W quadrant) by an angle of δ. When δ ≤ FOV / 2, that is, the laser radar is not far away from the alignment and the laser beam is still within the field of view of the telescope, it can be seen that the laser beam first moves in the direction of h. W The height enters the field of view of the W quadrant of the telescope, and then at h E The height enters the E quadrant of the telescope's field of view. Figure 5 The geometric relationship can be obtained:

[0114]

[0115] From the above two formulas, the angle of deviation of the laser beam can be obtained as follows:

[0116]

[0117] If h W <h E , indicating that the laser beam is deflected towards the W shading plate, and vice versa towards the E shading plate. Figure 2b You can see more clearly. Figure 2b The figure shows the signal diagram of a single light-transmitting area when the laser beam is in the centered state and the non-centered state with the telescope. 25 represents the signal P corresponding to the first light-transmitting area (light-transmitting unit W) when there is no alignment. W , 27 represents the optical signal P of the second light-transmitting area (light-transmitting unit E) when there is no alignment E . hw corresponds to the peak of the signal 25 profile, and h E Corresponding to the peak of the signal 27 profile, combined Figure 2a and Figure 2b , hw <h E, This means that the laser beam is deflected to the W shield, that is, the left side. 26 represents the signal when it is aligned. At this time, P W =P E =P N =P S ,

[0118] In engineering, it is generally believed that P W =P E and P N =P S It is considered that alignment has been achieved.

[0119] According to the above discussion, the process of detecting and adjusting the centering state of the laser radar can be obtained as follows: Figure 6 shown.

[0120] Figure 6 In step S401 , all four shading units W, N, E, and S are closed. At this time, no light enters the telescope 1 .

[0121] Step S402: Turn on W and obtain signal P W , then close W.

[0122] Step S403: Open E and obtain signal P E , then close E.

[0123] Step S404: Turn on W and obtain signal P W ', then close W.

[0124] Step S405: Determine P W With P W 'Are they consistent? If not, it means that the atmosphere is unstable during this period, and it is necessary to return to step S402 and repeat the above steps; if consistent, it means that the atmosphere is stable, and continue to the next step 406.

[0125] Step S406: Determine P W With P E If not, it means that the laser pointing direction has deviated. In step S407, according to formula 3, the deviation angle δ is calculated and the deviation direction is determined. In step S408, the action of adjusting δ in the WE direction is performed. Then, return to step S402 and repeat the above steps until P is determined in step S406. W With P E Completely consistent, proceed to the next step S502.

[0126] Step S502: Turn on N and obtain signal P N , then close N.

[0127] Step S503: Turn on S and obtain signal P S , then close S.

[0128] Step S504: Turn on N and obtain signal P N ', then close N.

[0129] Step S505: Determine P N Whether with P N If not, return to step S502 and repeat the above steps; if not, proceed to the next step S506.

[0130] Step S506: Determine P N With P S If not, it means there is a deviation in this direction. Step S507, calculate δ and determine the deviation direction according to formula 3. Step S508, adjust δ in the NS direction. Then, return to step 502 and repeat the above steps until P is determined in step S506. N With P S If they are consistent, the process goes to the next step S509, all the shading units are turned on, the radar is aligned, and it can start working.

[0131] Those skilled in the art will understand that the operation of the above-mentioned light-shielding unit is consistent with the operation of the corresponding light-transmitting area.

[0132] Because short-wavelength lidar signals are not sensitive to atmospheric changes, for lidars with shorter wavelengths (e.g., 355 nm) or at times and places where the atmosphere is relatively stable, in the above steps, steps S404 and S405, or steps S504 and S505 are not necessary and can be omitted.

[0133] The sunshade above uses a four-unit array, each unit is opened in a time-sharing manner, and combined with the time-sharing measurement of the detector, signals from different light-transmitting areas on the light-transmitting surface are obtained.

[0134] Figure 7 This is the case when the laser radar is in a non-coaxial layout, where the laser optical axis is not aligned with the optical axis of the telescope. The laser radar comprises a laser 71, a light detector 73, a telescope 72, and light shields 74 and 75 representing the aligned light.

[0135] Still Figure 3a As an example, compared to the sunshade Figure 3a The detection and adjustment principles for the shading device layout in the N and S directions are the same as for the coaxial direction. In the W and E directions, i.e., the first adjustment direction, because the laser optical axis does not necessarily have to be completely parallel to the optical axis of the telescope, the criterion for detection alignment is that the signals in the W and E quadrants must be completely consistent at a distance. See reference numeral 78. 75 represents the W signal profile, 77 represents the E signal profile, and their peak positions h W and h E It can be determined according to the needs. Similarly, in order to improve the signal-to-noise ratio and reduce the error, Figure 3b The layout also has the corresponding relationship as described above.

[0136] Figure 8a 、 Figure 8b Shown is a functional block diagram of a lidar system.

[0137] It can be seen that Figure 8a Corresponding to the coaxial design of the laser radar, Figure 8b Corresponding to non-coaxial design, 81 represents a laser, 82 represents a telescope, 83 represents a light detector, 84 represents a light shield, 85 represents a laser emission mirror, 86 represents a data acquisition module, 87 represents a motor drive, and 88 represents a control unit.

[0138] As can be seen from the figure, the coaxial lidar's sunshade has a central hole designed to facilitate laser emission, as the laser emitting mirror is located below the sunshade. However, the sunshade of a non-coaxial lidar design does not require a central hole. Of course, even in coaxial lidar designs, the sunshade can be designed without a central hole if the laser emitting mirror is located above the sunshade.

[0139] The operating process is as follows. Control unit 88 issues commands, which, via motor driver 87, drive shading plate 84 to open different shading sections. The electrical signals generated by light detector 83 are collected by data acquisition module 86 and fed back to control unit 88. Control unit 88 processes and determines the desired adjustment size and direction of the laser beam, then issues corresponding commands to motor driver 87 to drive the laser emission mirror to achieve centering adjustment in the first and / or second adjustment directions.

[0140] This invention can automatically detect whether the laser radar's transmitted laser beam is aligned with the optical axis of the receiving telescope and automatically correct optical alignment errors, resolving the problem of ensuring laser radar optical alignment accuracy, which requires specialized personnel. It also addresses the alignment failures caused by traditional automatic alignment algorithms, which take too long to scan in two directions and have difficulty ensuring consistent atmospheric conditions. The advantages are as follows:

[0141] (1) Automatically detect the optical alignment status of the LiDAR system and automatically correct alignment deviations without the involvement of professional technicians, thereby improving alignment accuracy and reducing alignment time. Compared with existing LiDAR automatic alignment algorithms, the requirements for atmospheric stability during alignment detection are greatly reduced, thereby improving the success rate of automatic alignment.

[0142] (2) Divide the optical telescope into four equally divided quadrants and add four light shields. According to the geometric symmetry relationship, if the laser radar is in a completely centered state, the laser radar signals obtained by opening the light shields in symmetrical positions should be equal. On the contrary, if the signals are inconsistent, it can be known that the optical system is not centered, and the direction and size of the laser beam pointing deviation can be judged from the difference between the two signals. Since only two signals need to be compared, the requirements for atmospheric stability are lower than those of the scanning centering algorithm (which requires comparison of about 10 signals), the centering success rate is higher, the centering accuracy is higher, and the time required is shorter. Compared with manual centering, automatic centering can be unmanned.

[0143] The present invention has been described above with reference to specific embodiments. In the specific embodiments, a reflecting telescope is used as an example, wherein the focal plane is located at the vertex of the secondary mirror of the telescope. Those skilled in the art will appreciate that this is not a requirement, and other types of telescopes, such as a Newtonian telescope, are also feasible.

[0144] In the description of the utility model, it should be understood that the terms "center," "lateral," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating positions or locations, are based on the positions or locations shown in the accompanying drawings and are intended solely to facilitate the description of the utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed to indicate or imply relative importance or to implicitly specify the quantity of the technical features referred to. In the description of the utility model, unless otherwise specified, "plurality" means two or more.

Claims

1. A laser radar with a centering device, the laser radar comprising a transmitting laser (21, 71, 81), a receiving telescope (22, 72, 82), and a light detector (23, 73, 83), and the laser radar comprising a first adjustment direction for adjusting a centering deviation of the transmitted laser and a second adjustment direction perpendicular to the first adjustment direction, characterized in that The laser radar further includes a shading device, which includes a shading plate (24, 74, 84) having at least one light-transmitting unit (W, E, N, S, A, B, C, D, 41) and is arranged at the echo light entrance of the telescope (22, 72, 82) for spatially modulating the echo light so that only one light-transmitting area (11, 12, 13, 14) on the light-transmitting surface of the echo light entrance of the telescope can transmit light and be detected by the light detector (23, 73, 83) within a specific time. By comparing the size and shape of the echo signals of two light-transmitting areas (11, 12, 13, 14) having a geometrically symmetrical relationship and arranged along a first adjustment direction, and / or comparing the size and shape of the echo signals of two light-transmitting areas having a geometrically symmetrical relationship and arranged along a second adjustment direction, the size and direction of the centering deviation in the corresponding adjustment direction can be detected, thereby performing centering adjustment in the corresponding adjustment direction of the laser radar.

2. The laser radar according to claim 1, wherein the light-transmitting areas (11, 12, 13, 14) are arranged as follows: In a Cartesian coordinate system having a first coordinate axis x and a second coordinate axis y, the first coordinate axis x and the second coordinate axis y divide the entrance light-transmitting surface into four equal parts. in, The first coordinate axis x is parallel to the first adjustment direction, and the second coordinate axis y is parallel to the second adjustment direction. The light-transmitting areas (11, 12, 13, 14) include a first light-transmitting area (11) and a second light-transmitting area (12), the first light-transmitting area (11) is arranged in the first quadrant and the fourth quadrant, and the second light-transmitting area (12) is arranged in the second quadrant and the third quadrant, or the first light-transmitting area (11) is arranged in the second quadrant and the third quadrant, and the second light-transmitting area (12) is arranged in the first quadrant and the fourth quadrant, The first light-transmitting area (11) and the second light-transmitting area (12) are symmetrical about the second coordinate axis y. The first light-transmitting area (11) has two states: light-transmitting and light-shielding; and the second light-transmitting area (12) has two states: light-transmitting and light-shielding.

3. The laser radar according to claim 2, wherein: The light-transmitting areas (11, 12, 13, 14) include a third light-transmitting area (13) and a fourth light-transmitting area (14), the third light-transmitting area (13) is arranged in the first quadrant and the second quadrant, and the fourth light-transmitting area (14) is arranged in the fourth quadrant and the third quadrant, or the third light-transmitting area (13) is arranged in the fourth quadrant and the third quadrant, and the fourth light-transmitting area (14) is arranged in the first quadrant and the second quadrant, The third light-transmitting area (13) and the fourth light-transmitting area (14) are symmetrical about the first coordinate axis x. The third light-transmitting area (13) has two states: light-transmitting and light-shielding; and the fourth light-transmitting area (14) has two states: light-transmitting and light-shielding.

4. The laser radar according to claim 3, wherein: The first light-transmitting area (11) and the second light-transmitting area (12) are respectively symmetrical about the first coordinate axis x.

5. The laser radar according to claim 3, wherein: The third light-transmitting area (13) and the fourth light-transmitting area (14) are respectively symmetrical about the second coordinate axis y.

6. The laser radar according to claim 4, wherein the first light-transmitting area (11) and the second light-transmitting area (12) are fan-shaped, and the vertex angle of the fan-shaped area with the coordinate origin as the vertex ranges from 90 degrees to 180 degrees.

7. The laser radar according to claim 6, wherein the third light-transmitting area (13) and the fourth light-transmitting area (14) are fan-shaped, and the vertex angle of the fan-shaped area with the coordinate origin as the vertex ranges from 90 degrees to 180 degrees.

8. The laser radar according to claim 2, wherein: If the detection signal (25) of the first light-transmitting area (11) is consistent with the detection signal (27) of the second light-transmitting area (12), the laser radar is centered in the first adjustment direction.

9. The laser radar as claimed in claim 3, wherein if the detection signal of the third light transmission area (13) is consistent with the detection signal of the fourth light transmission area (14), the laser radar is centered in the second adjustment direction.

10. The laser radar as claimed in claim 7, wherein the fan-shaped vertex angles of the first light-transmitting area (11), the second light-transmitting area (12), the third light-transmitting area (13) and the fourth light-transmitting area (14) are 90 degrees, and the shading plate includes a first unit (W), a second unit (E), a third unit (N) and a fourth unit (S), each unit can be opened and closed independently to allow light to pass and block light, and when in use, the shading plate is fixed on the echo light entrance of the telescope, and the first unit (W), the second unit (E), the third unit (N) and the fourth unit (S) correspond to the first light-transmitting area (11), the second light-transmitting area (12), the third light-transmitting area (13) and the fourth light-transmitting area (14), respectively.

11. The laser radar as claimed in claim 7, wherein the fan-shaped vertex angles of the first light-transmitting area (11), the second light-transmitting area (12), the third light-transmitting area (13) and the fourth light-transmitting area (14) are 180 degrees, and the shading plate includes a first unit (A), a second unit (B), a third unit (C) and a fourth unit (D), each unit can be opened and closed independently to allow light to pass through and block light. When in use, the shading plate is fixed to the echo light entrance of the telescope, the first unit (A) and the third unit (C) can be opened or closed at the same time and correspond to the first light-transmitting area (11), the second unit (B) and the fourth unit (D) can be opened or closed at the same time and correspond to the second light-transmitting area (12), the first unit (A) and the second unit (B) can be opened or closed at the same time and correspond to the third light-transmitting area (13), and the third unit (C) and the fourth unit (D) can be opened or closed at the same time and correspond to the fourth light-transmitting area (14).

12. The laser radar according to claim 7, wherein the light shielding plate comprises a fan-shaped light-transmitting unit (41) corresponding to the shape of the light-transmitting area (11, 12, 13, 14) and capable of transmitting light. The other parts are light-shielded. When in use, the light-transmitting unit (41) is mounted on the echo light entrance and rotates. When the light-transmitting unit (41) coincides with the first light-transmitting area (11), the light detector (23, 73, 83) can detect the echo signal from the first light-transmitting area (11); when the light-transmitting unit (41) coincides with the second light-transmitting area (12), the light detector (23, 73, 83) can detect the echo signal from the second light-transmitting area (12); when the light-transmitting unit (41) coincides with the third light-transmitting area (13), the light detector (23, 73, 83) can detect the echo signal from the third light-transmitting area (13); when the light-transmitting unit (41) coincides with the fourth light-transmitting area (14), the light detector (23, 73, 83) can detect the echo signal from the fourth light-transmitting area (14).

13. The laser radar according to claim 12, wherein the light shielding plate comprises a fan-shaped light-transmitting unit (41) capable of transmitting light and corresponding to the shape of the light-transmitting area, and the vertex angle of the fan is 90 degrees or 180 degrees.

14. A method for detecting and adjusting the centering of a laser radar, wherein the laser radar comprises a transmitting laser (21, 71, 81), a receiving telescope (22, 72, 82), and a light detector (23, 73, 83), and the laser radar comprises a first adjustment direction for adjusting the centering deviation of the transmitting laser and a second adjustment direction perpendicular to the first adjustment direction, wherein the method is characterized in that A shading device comprises a shading plate (24, 74, 84), the shading plate having at least one light-transmitting unit (W, E, N, S, A, B, C, D, 41), arranged at the echo light entrance of the telescope (22, 72, 82), and used for spatially modulating the echo light so that on the light-transmitting surface of the echo light entrance of the telescope, only one light-transmitting area (11, 12, 13, 14) can transmit light to be detected by the light detector (23, 73, 83) within a specific time. By comparing the size and shape of the echo signals of two light-transmitting areas (11, 12, 13, 14) having a geometrically symmetrical relationship and arranged along a first adjustment direction, and / or comparing the size and shape of the echo signals of two light-transmitting areas having a geometrically symmetrical relationship and arranged along a second adjustment direction, the size and direction of the centering deviation in the corresponding adjustment direction can be detected, thereby performing centering adjustment in the corresponding adjustment direction of the laser radar.

15. The method according to claim 14, wherein the light-transmitting areas (11, 12, 13, 14) are arranged as follows: In a Cartesian coordinate system having a first coordinate axis x and a second coordinate axis y, the first coordinate axis x and the second coordinate axis y divide the entrance light-transmitting surface into four equal parts. in, The first coordinate axis x is parallel to the first adjustment direction, and the second coordinate axis y is parallel to the second adjustment direction. The light-transmitting areas (11, 12, 13, 14) include a first light-transmitting area (11) and a second light-transmitting area (12), the first light-transmitting area (11) is arranged in the first quadrant and the fourth quadrant, and the second light-transmitting area (12) is arranged in the second quadrant and the third quadrant, or the first light-transmitting area (11) is arranged in the second quadrant and the third quadrant, and the second light-transmitting area (12) is arranged in the first quadrant and the fourth quadrant, The first light-transmitting area (11) and the second light-transmitting area (12) are symmetrical about the second coordinate axis y. The first light-transmitting area (11) has two states: light-transmitting and light-shielding; and the second light-transmitting area (12) has two states: light-transmitting and light-shielding.

16. The method of claim 15, further comprising a third light-transmitting area (13) and a fourth light-transmitting area (14), wherein the third light-transmitting area (13) is arranged in the first quadrant and the second quadrant, and the fourth light-transmitting area (14) is arranged in the fourth quadrant and the third quadrant, or the third light-transmitting area (13) is arranged in the fourth quadrant and the third quadrant, and the fourth light-transmitting area (14) is arranged in the first quadrant and the second quadrant, in, The third light-transmitting area (13) and the fourth light-transmitting area (14) are symmetrical about the first coordinate axis x. The third light-transmitting area (13) has two states: light-transmitting and light-shielding; and the fourth light-transmitting area (14) has two states: light-transmitting and light-shielding.

17. The method of claim 15, wherein when measuring and adjusting the centering deviation in the first adjustment direction, the method comprises: Step 1: The first light-transmitting area (11) is light-transmitting, the second light-transmitting area (12) is light-shielded, and the light detector (23, 73, 83) detects a first light signal from the first light-transmitting area (11); Step 2: The second light-transmitting area allows light (12), the first light-transmitting area blocks light (11), and the light detector (23, 73, 83) detects a second light signal from the second light-transmitting area (12); Step 3: Compare the first optical signal and the second optical signal. If the two are consistent, it means that the laser radar is well aligned in the first adjustment direction of the laser emission corresponding to the second light-transmitting area and the third light-transmitting area, and the measurement is completed. If the two are inconsistent, performing centering adjustment in the first adjustment direction of the emitted laser light according to the deviation between the first optical signal and the second optical signal; Repeat the above steps until the first optical signal and the second optical signal are consistent.

18. The method of claim 17, wherein when measuring and adjusting the centering deviation in the second adjustment direction, the method comprises the following steps: Step 4: the third light-transmitting area (13) is light-transmitted, the first light-transmitting area (11), the second light-transmitting area (12) and the fourth light-transmitting area (14) are shielded, and the light detectors (23, 73, 83) detect a third light signal from the third light-transmitting area (13); Step 5: the fourth light-transmitting area (14) is light-transmitted, the first light-transmitting area (11), the second light-transmitting area (12) and the third light-transmitting area (13) are shielded from light, and the light detector detects (23, 73, 83) a fourth light signal from the fourth light-transmitting area (14); Step 6: Compare the third light signal and the fourth light signal. If the two are consistent, it means that the laser radar is well aligned in the second adjustment direction of the laser emission corresponding to the third light-transmitting area (13) and the fourth area (14), and the measurement is completed. If the two are inconsistent, performing centering adjustment in the second adjustment direction of the emitted laser light according to the deviation of the third optical signal (13) and the fourth optical signal (14); Repeat the above steps until the third optical signal and the fourth optical signal are consistent.

19. The method of claim 15, wherein: The first light-transmitting area and the second light-transmitting area are symmetrical about the first coordinate axis x.

20. The method of claim 16, wherein: The third light-transmitting area and the fourth light-transmitting area are symmetrical about the second coordinate axis y.

21. The method of claim 17, wherein: Between step 2 and step 3, the following steps are also included: The first light-transmitting area allows light (11), the second light-transmitting area (12) blocks light, and the light detector (23, 73, 83) measures the first light signal from the first area again; Compare the first optical signals before and after the first optical signal, if they are consistent, proceed to step 3, if not, Return to step 1.

22. The method of claim 18, wherein: Between step 4 and step 5, the following steps are also included: The third light-transmitting area (13) is light-transmitted, the first light-transmitting area (11), the second light-transmitting area (12) and the fourth light-transmitting area (14) are shielded from light, and a third light signal from the third light-transmitting area (13) is measured again; Compare the third optical signals before and after twice. If they are consistent, proceed to step 6. If they are inconsistent, Go back to step 4.

23. The method according to claim 16, wherein the first light-transmitting area (11) and the second light-transmitting area (12) are fan-shaped, and the vertex angle of the fan-shaped area with the coordinate origin as the vertex ranges from 90 degrees to 180 degrees.

24. The method according to claim 23, wherein the third light-transmitting area (13) and the fourth light-transmitting area (14) are fan-shaped, and the vertex angle of the fan-shaped area with the coordinate origin as the vertex ranges from 90 degrees to 180 degrees.

25. The method of claim 24, wherein the fan-shaped vertex angles of the first light-transmitting area (11), the second light-transmitting area (12), the third light-transmitting area (13) and the fourth light-transmitting area (14) are 90 degrees, and the light shielding plate comprises a first unit (W), a second unit (E), a third unit (N) and a fourth unit (S), each unit can be opened and closed independently to allow light to pass through and block light, and when in use, the light shielding plate is fixed on the echo light entrance of the telescope, and the first unit (W), the second unit (E), the third unit (N) and the fourth unit (S) correspond to the first light-transmitting area (11), the second light-transmitting area (12), the third light-transmitting area (13) and the fourth light-transmitting area (14), respectively.

26. The method of claim 24, wherein the fan-shaped vertex angles of the first light-transmitting area (11), the second light-transmitting area (12), the third light-transmitting area (13) and the fourth light-transmitting area (14) are 180 degrees, the shading plate comprises a first unit (A), a second unit (B), a third unit (C) and a fourth unit (D), each unit can be opened and closed independently to allow light to pass through and block light, and when in use, the shading plate is fixed to the echo light entrance of the telescope, the first unit (A) and the third unit (C) can be opened or closed at the same time and correspond to the first light-transmitting area (11), the second unit (B) and the fourth unit (D) can be opened or closed at the same time and correspond to the second light-transmitting area (12), the first unit (A) and the second unit (B) can be opened or closed at the same time and correspond to the third light-transmitting area (13), and the third unit (C) and the fourth unit (D) can be opened or closed at the same time and correspond to the fourth light-transmitting area (14).

27. The method according to claim 24, wherein the light shielding plate comprises a fan-shaped light-transmitting unit (41) corresponding to the shape of the light-transmitting area and capable of transmitting light. The other parts are light-shielded. When in use, the light-transmitting unit (41) is mounted on the echo light entrance and rotates. When the light-transmitting unit (41) coincides with the first light-transmitting area (11), the light detector (23, 73, 83) can detect the echo signal from the first light-transmitting area (11); when the light-transmitting unit (41) coincides with the second light-transmitting area (12), the light detector (23, 73, 83) can detect the echo signal from the second light-transmitting area (12); when the light-transmitting unit (41) coincides with the third light-transmitting area (13), the light detector (23, 73, 83) can detect the echo signal from the third light-transmitting area (13); when the light-transmitting unit (41) coincides with the fourth light-transmitting area (14), the light detector (23, 73, 83) can detect the echo signal from the fourth light-transmitting area (14).

28. The method according to claim 27, wherein the light shielding plate comprises a fan-shaped light-transmitting unit (41) corresponding to the shape of the light-transmitting area and capable of transmitting light, and the vertex angle of the fan-shaped unit is 90 degrees or 180 degrees.

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