An airborne circularly polarized anti-jamming lidar device

Abstract

This application discloses an airborne circularly polarized anti-jamming lidar device, comprising: a transmitting module for transmitting circularly polarized illumination light into a target environment; a receiving module for receiving measurement light corresponding to the circularly polarized illumination light from the target environment; and a separating module for separating circularly polarized reflected light from the measurement light. The separating module includes a first polarization detection unit, which includes a housing, a polarizing plate, a rotating sleeve, and a first waveplate. The housing has a mounting cavity and a light inlet communicating with the mounting cavity. The polarizing plate is disposed within the mounting cavity. The rotating sleeve is rotatably disposed within the housing and located at the light inlet. The first waveplate is positioned within the rotating sleeve. The rotating sleeve is configured to rotate relative to the housing under external force to adjust the fast axis angle of the first waveplate. By applying this application, the first waveplate can be rotated by the rotating sleeve to adjust its fast axis angle, thereby improving the measurement accuracy and precision of the airborne circularly polarized anti-jamming lidar device.

Description

Technical Field

[0001] This application relates to the field of detection instrument technology, specifically to an airborne circular polarization anti-interference lidar device. Background Technology

[0002] The weak underwater laser echo signal of marine lidar is easily interfered with by sunlight background noise and multiple scattering of light from the water, causing the effective echo signal to be submerged in background noise. This greatly limits the effective detection range and accuracy of marine lidar. To address this, a novel airborne circularly polarized anti-interference lidar device capable of emitting and receiving circularly polarized light has been developed. Since natural light does not contain circularly polarized components, and the circularly polarized components degenerate into linearly polarized components in the multiple scattering of light from the water, the observed circularly polarized components theoretically originate entirely from the backscattered laser signal of the target, thus achieving high-precision, high signal-to-noise ratio measurements.

[0003] Currently, there is no mature airborne circularly polarized anti-interference lidar device. Based on the principle of circularly polarized light detection, the system performance places high demands on the installation accuracy of the waveplate, ensuring that the angle between the fast axis of the waveplate and the incident light axis is precisely controllable. If this angle deviates significantly, the measured polarized light will not be ideally circularly polarized, thus weakening or even failing to meet the expected anti-interference performance. Therefore, it is necessary to reserve and design an adjustable structure in the design to fine-tune the waveplate angle, thereby ensuring accurate circularly polarized light detection results. Utility Model Content

[0004] This application aims to address one of the technical problems in related technologies to a certain extent. To this end, this application provides an airborne circularly polarized anti-jamming lidar device.

[0005] To achieve the above objectives, this application adopts the following technical solution: an airborne circular polarization anti-jamming lidar device, comprising:

[0006] The transmitting module is used to emit circularly polarized illumination light into the target environment;

[0007] A receiving module for receiving measurement light corresponding to the circularly polarized illumination light from the target environment; and,

[0008] A separation module for separating circularly polarized reflected light from the measurement light;

[0009] The separation module includes a first polarization detection unit, which includes a housing, a polarizing plate, a rotating sleeve, and a first waveplate. The housing has a mounting cavity and an inlet communicating with the mounting cavity. The polarizing plate is disposed in the mounting cavity. The rotating sleeve is rotatably disposed on the housing and located at the inlet. The first waveplate is positioned inside the rotating sleeve. The rotating sleeve is configured to rotate relative to the housing under external force to adjust the fast axis angle of the first waveplate.

[0010] The application of this application has the following beneficial effects: By setting a first polarization unit, the measurement light corresponding to the circularly polarized illumination light can be separated, separating the required circularly polarized component and part of the linearly polarized light from the other part of the linearly polarized light, thereby enabling the analysis and acquisition of the signal of the required circularly polarized component. A rotating sleeve that can rotate relative to the housing is set in the first polarization unit. Positioning the first waveplate within the rotating sleeve allows the first waveplate to rotate relative to the housing via the rotating sleeve, adjusting the fast axis angle of the first waveplate. Calibration using a polarization measuring instrument from the outside can accurately adjust the fast axis angle of the first waveplate to 45° with the optical axis of the measurement light. This improves the measurement accuracy and precision of the airborne circularly polarized anti-interference lidar device.

[0011] Optionally, the first polarization detection unit further includes a positioning flange fixedly disposed on the housing and located at the light inlet. The positioning flange is provided with a radially extending threaded hole and a set screw screwed into the threaded hole. The rotating sleeve passes through the positioning flange and is positioned on the housing by the set screw.

[0012] Optionally, the first polarization analyzer unit further includes a filter positioned within a rotating sleeve, the filter being parallel to and spaced apart from the first waveplate, and the filter being positioned away from the polarization plate relative to the first waveplate.

[0013] Optionally, the housing is further provided with a first light-emitting port and a second light-emitting port communicating with the mounting cavity. A signal light path is formed between the first light-emitting port and the light-in port, and a noise light path is formed between the second light-emitting port and the light-in port. The separation module further includes a first photomultiplier tube disposed at the first light-emitting port and a second photomultiplier tube disposed at the second light-emitting port.

[0014] Optionally, the airborne circularly polarized anti-interference lidar device further includes a housing, the housing forming a cavity and having a light-emitting hole and a light-receiving hole on one side. The transmitting module emits circularly polarized illumination light outward through the light-emitting hole, and the receiving module receives measurement light through the light-receiving hole. The airborne circularly polarized anti-interference lidar device further includes a mounting frame disposed within the cavity. The mounting frame includes a support portion, an extension portion, and a mounting portion. The mounting frame divides the cavity into a first accommodating space and a second accommodating space. The separating module is disposed in the support portion, the transmitting module is disposed in the first accommodating space and the mounting portion, and the receiving module is disposed in the second accommodating space and extends to engage with the separating module.

[0015] Optionally, the receiving module includes a telescope disposed in the second accommodating space, the light-emitting side of the telescope extending to be in sealed communication with the rotating sleeve.

[0016] Optionally, the mounting part includes a mounting shell with a hollow cavity, and the emitting module includes a laser emitter and a plane mirror assembly. The mounting shell is provided with a first opening aligned with the emission port of the laser emitter and a second opening aligned with the light emission port. The laser emitter is disposed in a first accommodating space, and the plane mirror assembly is disposed in the hollow cavity. The plane mirror assembly is used to emit the laser emitted by the laser emitter to the second opening.

[0017] Optionally, the transmitting module further includes a second polarization detection unit. The second polarization detection unit includes a screw sleeve rotatably disposed on the mounting part and a second wave plate positioned inside the screw sleeve. The screw sleeve is located between the second opening and the light emission hole. The screw sleeve is configured to rotate relative to the outer shell under the action of external force to adjust the fast axis angle of the second wave plate.

[0018] Optionally, the planar mirror assembly includes two planar mirror units. Each planar mirror unit includes a mounting bracket disposed on the mounting portion and a reflective mirror disposed on the mounting bracket. The mounting bracket is configured to move relative to the mounting portion to adjust the pitch angle and yaw angle of the reflective mirror relative to the first opening.

[0019] Optionally, the mounting bracket includes a first connecting plate located outside the mounting portion and a second connecting plate extending into the mounting portion. The reflective lens is disposed on the second connecting plate. The first connecting plate is provided with a plurality of arc-shaped holes distributed circumferentially. The mounting bracket is locked and fixed to the mounting portion by screws passing through the arc-shaped holes.

[0020] These features and advantages of this application will be disclosed in detail in the following specific embodiments and accompanying drawings. The best embodiments or means of this application will be shown in detail in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of this application. In addition, each of these features, elements and components appearing in the following text and drawings is multiple and is labeled with different symbols or numbers for convenience, but all represent parts with the same or similar structure or function. Attached Figure Description

[0021] The following description, in conjunction with the accompanying drawings, further illustrates this application:

[0022] Figure 1 A schematic diagram of the structure of an airborne circular polarization anti-jamming lidar device provided in this application embodiment;

[0023] Figure 2 This is an exploded view of an airborne circular polarization anti-jamming lidar device.

[0024] Figure 3 An exploded view of the separation module;

[0025] Figure 4 A schematic diagram of the mounting frame and the second detection unit;

[0026] Figure 5 Exploded view of the mounting frame and the second detection unit.

[0027] The components include: 1. Transmitting module; 10. Laser emitter; 11. Plane reflector unit; 110. Mounting bracket; 1100. First connecting plate; 1101. Second connecting plate; 1102. Arc-shaped hole; 1103. Mounting hole; 111. Reflecting mirror; 12. Tightening sleeve; 2. Receiving module; 3. Separating module; 30. First polarization analyzer unit; 300. Housing; 3000. Light inlet; 3001. First light outlet; 30. 02. Second light outlet; 301. Polarizing plate; 302. Rotating sleeve; 303. First waveplate; 304. Positioning flange; 3040. Threaded hole; 305. Filter; 31. First photomultiplier tube; 32. Second photomultiplier tube; 4. Housing; 40. Light outlet; 41. Light inlet; 42. Protective lens; 5. Mounting frame; 50. Support; 51. Extension; 52. Mounting part; 520. Second opening. Detailed Implementation

[0028] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described are intended to explain this application and should not be construed as limiting it.

[0029] The terms "an embodiment," "example," or "example" used in this specification refer to a particular feature, structure, or characteristic described in connection with the embodiment itself that may be included in at least one embodiment disclosed in this application. The phrase "in an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0030] In the description of this application, it should be understood that the terms "upper," "lower," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In the description of this application, "a plurality of" means two or more, unless otherwise precisely specified.

[0031] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected," "linked," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a connection through an intermediary, or a connection within two elements or an interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0032] This embodiment provides an airborne circular polarization anti-jamming lidar device, such as... Figure 1 and Figure 2 As shown, the airborne circularly polarized anti-jamming lidar device includes a transmitting module 1, a receiving module 2, and a separating module 3. The transmitting module 1 transmits circularly polarized illumination light into the target environment, the receiving module 2 receives measurement light corresponding to the circularly polarized illumination light from the target environment, and the separating module 3 separates the circularly polarized reflected light from the measurement light.

[0033] The separation module 3 includes a first polarization detection unit 30, which includes a housing 300, a polarizing plate 301, a rotating sleeve 302, and a first wave plate 303. The housing 300 is provided with a mounting cavity and an inlet 3000 communicating with the mounting cavity. The polarizing plate 301 is disposed in the mounting cavity. The rotating sleeve 302 is rotatably disposed in the housing 300 and located at the inlet 300. The first wave plate 303 is positioned in the rotating sleeve 302. The rotating sleeve 302 is configured to be able to rotate relative to the housing 300 under the action of external force to adjust the fast axis angle of the first wave plate 303.

[0034] By setting up a first polarization unit, the measurement light corresponding to the circularly polarized illumination light can be separated, separating the required circularly polarized component and a portion of the linearly polarized light from the other portion of the linearly polarized light, thereby allowing analysis to obtain the signal of the required circularly polarized component. A rotating sleeve 302, rotatable relative to the housing 300, is provided in the first polarization unit. Positioning the first waveplate 303 within the rotating sleeve 302 allows the first waveplate 303 to rotate relative to the housing 300 via the rotating sleeve 302, adjusting the fast axis angle of the first waveplate 303. Calibration using a polarization measuring instrument externally can accurately adjust the fast axis angle of the first waveplate 303 to 45° with the optical axis of the measurement light. This improves the measurement accuracy and precision of the airborne circularly polarized anti-interference lidar device. It should be noted that the polarization measuring instrument is an existing product and can be directly purchased from the market; its working principle will not be elaborated further.

[0035] Specifically, in combination Figure 3 As shown, the first polarization detection unit 30 in this embodiment also includes a positioning flange 304 fixedly disposed on the housing 300 and located at the light inlet 3000. The positioning flange 304 is provided with a radially extending threaded hole 3040 and a set screw (not shown in the figure) screwed into the threaded hole 3040. The rotating sleeve 302 passes through the positioning flange 304 and is positioned on the housing 300 by the set screw. With the above structural design, when it is necessary to adjust the first wave plate 303, the set screw can be loosened, and the first wave plate 303 can be rotated by turning the rotating sleeve 302. After the first wave plate 303 is rotated into position, the rotating sleeve 302 can be locked and fixed on the positioning flange 304 by tightening the set screw, thereby ensuring the stability of the first wave plate 303 relative to the housing 300.

[0036] Furthermore, the first polarization detection unit 30 in this embodiment also includes a filter 305 positioned within the rotating sleeve 302. The filter 305 is parallel to and spaced apart from the first waveplate 303, and the filter 305 is positioned away from the polarization plate 301 relative to the first waveplate 303. For the measurement light corresponding to the circularly polarized illumination light, the filter 305 can eliminate some of the interference from stray light in advance, further improving the measurement accuracy and precision of the airborne circularly polarized anti-interference lidar device.

[0037] Combination Figure 2 and Figure 3As shown, in this embodiment, the housing 300 is further provided with a first light-emitting port 3001 and a second light-emitting port 3002 communicating with the mounting cavity. A signal optical path is formed between the first light-emitting port 3001 and the light-in port 3000, and a noise optical path is formed between the second light-emitting port 3002 and the light-in port 3000. The separation module 3 also includes a first photomultiplier tube 31 disposed at the first light-emitting port 3001 and a second photomultiplier tube 32 disposed at the second light-emitting port 3002. Specifically, by setting the signal optical path and the noise optical path, the required circularly polarized component and part of the linearly polarized light can be guided to the first photomultiplier tube 31 through the signal optical path, while another part of the linearly polarized light is guided to the second photomultiplier tube 32. A photomultiplier tube (PMT) is a high-sensitivity, high-gain photodetector that can convert extremely weak light signals (such as weak light at the level of a single photon) into measurable and amplifiable electrical signals. By setting the first photomultiplier tube 31 and the second photomultiplier tube 32 to receive the optical signal of the measurement light and convert it into an electrical signal, the measurement accuracy and precision of the airborne circular polarization anti-interference lidar device can be further improved.

[0038] Combination Figure 1 and Figure 4 As shown, the airborne circularly polarized anti-interference lidar device provided in this embodiment also includes a housing 4. A cavity is formed within the housing 4, and a light-emitting hole 40 and a light-entry hole 41 are provided on one side wall of the housing 4. The transmitting module 1 emits circularly polarized illumination light outward through the light-emitting hole 40, and the receiving module 2 receives the measurement light through the light-entry hole 41. The airborne circularly polarized anti-interference lidar device also includes a mounting frame 5 disposed within the cavity. The mounting frame 5 includes a support portion 50, an extension portion 51, and a mounting portion 52, and the mounting frame 5 divides the cavity into a first accommodating space and a second accommodating space. The separation module 3 is disposed on the support portion 50, the transmitting module 1 is disposed in the first accommodating space and the mounting portion 52, and the receiving module 2 is disposed in the second accommodating space and extends to engage with the separation module 3. The above structural arrangement allows for a reasonable layout of the transmitting module 1 and the receiving module 2, reducing space occupation.

[0039] The receiving module 2 in this embodiment includes a telescope disposed in the second accommodating space, with the light-emitting side of the telescope extending to be sealed and connected to the rotating sleeve 302. It should be noted that the side of the telescope connected to the light inlet 41 of the outer casing 4 is the light-inlet side of the telescope, and the end of the telescope away from the aforementioned light-inlet side is the aforementioned light-emitting side.

[0040] In addition, in this embodiment, a protective lens 42 is provided at the light outlet 40 and light inlet 41 of the housing 4. The protective lens 42 can improve the sealing of the housing 4 and prevent external dust, moisture and other substances from contaminating the internal optical components.

[0041] Combination Figure 4 and Figure 5 As shown, the mounting part 52 in this embodiment includes a mounting shell with a hollow cavity, and the emitting module 1 includes a laser emitter 10 and a plane mirror assembly. The mounting shell is provided with a first opening (not shown in the figure) aligned with the emission port of the laser emitter 10 and a second opening 520 aligned with the light emission port 40. The laser emitter 10 is disposed in the first accommodating space, and the plane mirror assembly is disposed in the hollow cavity. The plane mirror assembly is used to emit the laser emitted by the laser emitter 10 to the second opening 520.

[0042] Furthermore, the transmitting module 1 in this embodiment also includes a second polarization detection unit, which includes a screw sleeve 12 rotatably disposed on the mounting part 52 and a second waveplate positioned within the screw sleeve 12. It is readily understood that the second polarization detection unit in this embodiment has a structure and function largely the same as the first polarization detection unit 30. Specifically, the second polarization detection unit is used to modulate the illumination light from the transmitting side to ensure that the illumination light is circularly polarized light with an ellipticity of approximately 45°. The first polarization detection unit 30 is used to modulate the received light from the receiving side to ensure that the measured light is circularly polarized light with an ellipticity close to 45°. This improves the measurement accuracy and precision of the airborne circularly polarized anti-interference lidar device.

[0043] By providing a rotating sleeve 12 in the second polarization unit that can rotate relative to the mounting part 52, the second waveplate is positioned inside the rotating sleeve 12. The rotating sleeve 12 then drives the second waveplate to rotate relative to the mounting part 52, thereby adjusting the fast axis angle of the second waveplate. Calibration using a polarization measuring instrument from the outside allows for accurate adjustment of the fast axis angle of the second waveplate to 45° with the optical axis of the irradiated light. Specifically, the rotating sleeve 12 is located between the second opening 520 and the light exit hole 40. The rotating sleeve 12 is configured to rotate relative to the outer casing 4 under external force to adjust the fast axis angle of the second waveplate. It is easy to understand that the rotating sleeve 12 also has a screw hole for screwing the set screw.

[0044] The planar mirror assembly in this embodiment includes two planar mirror units 11. Each planar mirror unit 11 includes a mounting bracket 110 disposed on the mounting portion 52 and a reflecting mirror 111 disposed on the mounting bracket 110. The mounting bracket 110 is configured to move relative to the mounting portion 52 to adjust the pitch and yaw angles of the reflecting mirror 111 relative to the first opening. Specifically, in conjunction with... Figure 5As shown, the mounting bracket 110 in this embodiment includes a first connecting plate 1100 located outside the mounting portion 52 and a second connecting plate 1101 extending into the mounting portion 52. The first connecting plate 1100 has a plurality of circumferentially distributed arc-shaped holes 1102, and the second connecting plate 1101 has mounting holes 1103. The reflective lens 111 is disposed within the mounting holes 1103 on the second connecting plate 1101. The mounting bracket 110 is locked and fixed to the mounting portion 52 by screws passing through the arc-shaped holes 1102.

[0045] When it is necessary to adjust the tilt angle of the reflector 111 relative to the first opening, it can be adjusted by rotating the mounting bracket 110 relative to the mounting part 52. After adjustment, the mounting bracket 110 is locked and fixed to the mounting part 52 by screws passing through the arc-shaped hole 1102. When it is necessary to adjust the pitch angle of the reflector 111 relative to the first opening, it can be adjusted by adding a shim between the first connecting plate 1100 and the top wall of the mounting part 52.

[0046] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Those skilled in the art should understand that this application includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of this application will be included within the scope of the claims.

Claims

1. An airborne circular polarization anti-interference lidar device, characterized in that, include: The transmitting module is used to emit circularly polarized illumination light into the target environment; A receiving module for receiving measurement light corresponding to the circularly polarized illumination light from the target environment; and, A separation module for separating circularly polarized reflected light from the measurement light; The separation module includes a first polarization detection unit, which includes a housing, a polarizing plate, a rotating sleeve, and a first waveplate. The housing has a mounting cavity and an inlet communicating with the mounting cavity. The polarizing plate is disposed in the mounting cavity. The rotating sleeve is rotatably disposed on the housing and located at the inlet. The first waveplate is positioned inside the rotating sleeve. The rotating sleeve is configured to rotate relative to the housing under external force to adjust the fast axis angle of the first waveplate.

2. The airborne circular polarization anti-interference lidar device as described in claim 1, characterized in that, The first polarization detection unit also includes a positioning flange fixedly disposed on the housing and located at the light inlet. The positioning flange is provided with a radially extending threaded hole and a set screw screwed into the threaded hole. The rotating sleeve passes through the positioning flange and is positioned on the housing by the set screw.

3. The airborne circular polarization anti-interference lidar device as described in claim 1, characterized in that, The first polarization analyzer also includes a filter positioned inside a rotating sleeve. The filter is parallel to and spaced apart from the first waveplate, and the filter is positioned away from the polarizing plate relative to the first waveplate.

4. The airborne circular polarization anti-interference lidar device as described in claim 1, characterized in that, The housing is also provided with a first light-emitting port and a second light-emitting port communicating with the mounting cavity. A signal light path is formed between the first light-emitting port and the light-in port, and a noise light path is formed between the second light-emitting port and the light-in port. The separation module also includes a first photomultiplier tube disposed at the first light-emitting port and a second photomultiplier tube disposed at the second light-emitting port.

5. The airborne circular polarization anti-jamming lidar device as described in any one of claims 1 to 4, characterized in that, The airborne circularly polarized anti-interference lidar device also includes a housing, which forms a cavity and has a light-emitting hole and a light-inlet hole on one side. The transmitting module emits circularly polarized illumination light outward through the light-emitting hole, and the receiving module receives measurement light through the light-inlet hole. The airborne circular polarization anti-jamming lidar device further includes a mounting frame disposed within a cavity. The mounting frame includes a support portion, an extension portion, and a mounting portion. The mounting frame divides the cavity into a first accommodating space and a second accommodating space. The separation module is disposed in the support portion, the transmitting module is disposed in the first accommodating space and the mounting portion, and the receiving module is disposed in the second accommodating space and extends to engage with the separation module.

6. The airborne circular polarization anti-interference lidar device as described in claim 5, characterized in that, The receiving module includes a telescope disposed in the second accommodating space, the light-emitting side of the telescope extending to be in sealed communication with the rotating sleeve.

7. The airborne circular polarization anti-interference lidar device as described in claim 5, characterized in that, The mounting part includes a mounting shell with a hollow cavity, and the emitting module includes a laser emitter and a plane mirror assembly. The mounting shell is provided with a first opening aligned with the emitting hole of the laser emitter and a second opening aligned with the light output hole. The laser emitter is disposed in the first accommodating space, and the planar reflector group is disposed in the hollow cavity. The planar reflector group is used to reflect the laser emitted by the laser emitter to the second opening.

8. The airborne circular polarization anti-jamming lidar device as described in claim 7, characterized in that, The transmitting module further includes a second polarization detection unit, which includes a screw sleeve rotatably disposed on the mounting part and a second wave plate positioned inside the screw sleeve. The screw sleeve is located between the second opening and the light emission hole. The screw sleeve is configured to rotate relative to the outer shell under the action of external force to adjust the fast axis angle of the second wave plate.

9. The airborne circular polarization anti-interference lidar device as described in claim 7, characterized in that, The planar mirror assembly includes two planar mirror units. Each planar mirror unit includes a mounting bracket disposed on the mounting part and a reflective mirror disposed on the mounting bracket. The mounting bracket is configured to move relative to the mounting part to adjust the pitch angle and yaw angle of the reflective mirror relative to the first opening.

10. The airborne circular polarization anti-interference lidar device as described in claim 9, characterized in that, The mounting bracket includes a first connecting plate located outside the mounting part and a second connecting plate extending into the mounting part. The reflective lens is disposed on the second connecting plate. The first connecting plate is provided with a plurality of arc-shaped holes distributed circumferentially. The mounting bracket is locked and fixed to the mounting part by screws passing through the arc-shaped holes.

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