Transmit-receive integrated shipborne ocean laser radar optical system

Abstract

The invention relates to the technical field of laser radars, in particular to a transmitting-receiving integrated shipborne ocean laser radar optical system, which comprises a laser transmitter, a receiving-transmitting integrated shipborne ocean laser radar optical system and a transmitting-receiving integrated shipborne ocean laser radar optical system, the detection laser is reflected by the reflecting mirror, is expanded by the beam expanding optical assembly, then enters a water body to be detected, and is scattered by the water body to be detected to form echo signal light; the receiving telescope receives the echo signal light and outputs detection signal light; a light path limiting mirror group, a collimation optical assembly, a convergent lens group and a detector, wherein the detection signal light is imaged on the detector after being subjected to condensation processing of the light path limiting mirror, collimation processing of the collimation optical assembly and convergence of the convergent lens group in sequence; wherein the detection laser emitted after being reflected by the reflector is coaxial with the echo signal light. According to the invention, the energy loss in the laser detection process can be reduced and the signal-to-noise ratio of laser detection can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser radars, and in particular relates to a transceiver-integrated shipborne ocean laser radar optical system. Background Art

[0002] Marine LIDAR is an advanced technology that uses laser technology for ocean exploration. It mainly obtains information on the ocean surface and shallow ocean structure by emitting laser pulses and measuring their return time. This technology has wide applications in marine science, environmental monitoring, navigation safety and other fields.

[0003] The specific working principle of ocean LiDAR is to emit high-frequency laser pulses through the LiDAR system. After these laser pulses reach the ocean surface through the air, part of the light is reflected back by the sea surface or underwater objects. The LiDAR system receives the returned light signal and measures the time difference from the emission to the reception of the laser pulse. According to the round-trip time of the laser pulse and the intensity of the laser pulse, the distance, depth and other parameters of the sea surface or underwater objects are calculated. Through data processing, images or three-dimensional models of the ocean surface and underwater structures are generated. However, due to the limited penetration depth of laser pulses, it can usually only be used in shallow sea areas; in addition, turbid water and bubbles will scatter laser pulses, affecting data quality; severe weather conditions (such as haze and strong winds) may affect the performance of LiDAR; in addition, traditional ocean LiDAR adopts a non-coaxial design of the transmitting system and the receiving system, resulting in the echo signal cannot be fully received by the receiving system; or, in the past, a beam splitter was used to separate the transmitting signal and the receiving signal, resulting in energy loss. Summary of the invention

[0004] In view of this, the present invention aims to provide a shipborne ocean laser radar optical system with an integrated transmitter and receiver, which is at least beneficial to reducing the energy loss of laser detection and improving the signal-to-noise ratio of laser detection.

[0005] To achieve the above object, the technical solution created by the present invention is implemented as follows: The invention provides a transceiver-integrated shipborne ocean laser radar optical system, comprising: a laser transmitter, the laser transmitter is used to emit a detection laser; a reflector and a beam expander optical component, the detection laser is reflected by the reflector, and after being expanded by the beam expander optical component, it enters a water body to be measured, and is scattered by the water body to be measured to form an echo signal light; a receiving telescope, the receiving telescope receives the echo signal light and outputs the detection signal light; an optical path limiting mirror group, a collimating optical component, a converging lens group and a detector, the detection signal light is sequentially subjected to the focusing processing of the optical path limiting mirror, the collimating processing of the collimating optical component and the convergence of the converging lens group, and then imaged on the detector; wherein the detection laser emitted after being reflected by the reflector is coaxial with the echo signal light.

[0006] Furthermore, the transceiver-integrated shipborne ocean lidar optical system also includes a filter, which is arranged between the collimating optical component and the converging lens group.

[0007] Furthermore, the center wavelength of the filter is 532 nm.

[0008] Furthermore, the receiving telescope is a reflective RC telescope, which includes a primary mirror and a secondary mirror. The secondary mirror is arranged between the primary mirror and the beam expansion optical component. The surface of the secondary mirror facing the primary mirror is a beam receiving surface. The primary mirror receives the echo signal light and projects the echo signal light onto the beam receiving surface of the secondary mirror. The echo signal light is reflected by the beam receiving surface and then emitted from the reflective RC telescope.

[0009] Furthermore, the reflector is arranged on a side of the secondary mirror away from the primary mirror.

[0010] Furthermore, the laser emitter is a solid pulse laser, the beam waist diameter of the detection laser emitted by the solid pulse laser is 8 mm, and the divergence angle of the detection laser emitted by the solid pulse laser is 3 mrad.

[0011] Furthermore, the beam radius of the detection laser after being expanded by the beam expanding optical component is within the range of 30 mm to 40 mm at a distance of 2 meters from the beam expanding optical component.

[0012] Further, the aperture of the reflecting RC telescope is 50 mm, the field angle of the reflecting RC telescope is 20 mrad, and the F number of the reflecting RC telescope is 6.5.

[0013] Furthermore, the distance between the secondary mirror and the primary mirror is 43.779 mm.

[0014] Furthermore, the aperture of the primary mirror is 50 mm, the cone coefficient of the primary mirror is -1.052, the radius of curvature of the primary mirror is -109.400 mm, the aperture of the secondary mirror is 11.060 mm, the cone coefficient of the secondary mirror is -2.414, and the radius of curvature of the secondary mirror is 45.301 mm.

[0015] Compared with the prior art, the invention can achieve the following beneficial effects: the transceiver-integrated shipborne ocean laser radar optical system provided by the invention can perform laser radar detection of the ocean on a ship close to the sea surface, which is beneficial to increasing the detection depth and detection accuracy. Specifically, in the transceiver-integrated shipborne ocean laser radar optical system, a reflector is used to achieve the coaxiality of the detection laser and the echo signal light, which is beneficial to reduce the energy loss in the detection process, improve the signal-to-noise ratio of the detection, and realize high-precision measurement of the optical characteristic parameters of the seawater profile. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 A schematic diagram of the structure of a transceiver-integrated shipborne ocean laser radar optical system provided by an embodiment of the present invention; Figure 2 The output point array diagram of the beam expansion optical component described in the embodiment of the present invention is created; Figure 3 A schematic diagram of the energy concentration of the detector according to an embodiment of the present invention; Figure 4 A schematic diagram of the transmission path of the detection signal light according to an embodiment of the present invention; Figure 5 A schematic structural diagram of another transceiver-integrated shipborne ocean laser radar optical system provided for an embodiment of the present invention.

[0017] Explanation of the reference numerals: 10, laser transmitter; 11, transmitting mirror; 12, beam expansion optical component; 13, collimating optical component; 14, converging lens group; 15, detector; 20, receiving telescope; 21, secondary mirror; 22, primary mirror. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0019] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0020] In the description of the invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0021] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0022] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0023] refer to Figure 1 The present invention provides a transceiver-integrated shipborne ocean laser radar optical system, comprising: a laser transmitter 10, the laser transmitter 10 is used to emit a detection laser; a reflector 11 and a beam expander optical component 12, the detection laser is reflected by the reflector 11, and is incident on a water body to be measured after being expanded by the beam expander optical component 12, and is scattered by the water body to be measured to form an echo signal light; a receiving telescope 20, the receiving telescope 20 receives the echo signal light and outputs the detection signal light; an optical path limiting mirror group (not marked), a collimating optical component 13, a converging lens group 14 and a detector 15, the detection signal light is sequentially subjected to the focusing processing of the optical path limiting mirror, the collimating processing of the collimating optical component 13 and the convergence of the converging lens group 14, and then imaged on the detector 15; wherein the detection laser emitted after being reflected by the reflector 11 is coaxial with the echo signal light.

[0024] The design of the transmitting part and the receiving part of the transceiver-integrated shipborne ocean laser radar optical system provided in the embodiment of the present invention is conducive to ensuring efficient signal transmission and improving the accuracy of the measurement results. Specifically, the reflection effect of the reflector 11 is used to realize the coaxiality of the detection laser and the echo signal light, so as to achieve the effect of transceiver-integration. Compared with the beam splitter used in the traditional transceiver-integration, the energy loss is smaller, and the emission light path of the detection laser will not affect the receiving light path of the echo signal light. Specifically, the beam expansion optical component 12 is arranged between the reflector 11 and the water body to be measured, and the water body to be measured is seawater. The optical component 12 expands the detection laser reflected by the reflector 11 to increase the beam diameter of the detection laser and improve the beam quality and measurement accuracy of the detection laser. In addition, the beam diameter of the detection laser before expansion is small. Therefore, the reflection of the detection laser can be achieved by using a smaller reflector 11. If a beam expanding optical component 12 is set between the reflector 11 and the laser transmitter 10, a larger reflector 11 is required to reflect the detection laser. The larger reflector 11 is easy to block the echo signal light, so that the receiving telescope 20 cannot receive effective echo signal light.

[0025] Furthermore, the transceiver-integrated shipborne ocean laser radar optical system further includes a filter, which is arranged between the collimating optical component 13 and the converging lens group 14. The filter can effectively isolate stray light and improve the signal-to-noise ratio.

[0026] The detection signal light output by the receiving telescope 20 is processed by the lens group in the optical path limiting mirror group and is converged on the focal plane of the optical path limiting mirror group to shorten the length of the transmission optical path of the detection signal light. Then, it is collimated into parallel light by the collimating optical component 13. The detection signal light collimated into parallel light passes through the filter to filter out the background stray light, and is further concentrated by the converging lens group 14 and received by the detector 15, which is conducive to improving the receiving ability and resolution of the detector 15. The detector 15 converts the detection signal light into an electrical signal, performs data analysis and processing, and thus realizes the measurement of the optical properties of seawater. The optical properties can be the scattering properties and absorption properties of the detection laser.

[0027] That is to say, the transceiver-integrated shipborne ocean lidar optical system provided by the embodiment of the present invention improves the emission quality of the detection laser and the reception accuracy of the echo signal light, and has high-precision and high-reliability measurement capabilities in complex marine environments.

[0028] Furthermore, the center wavelength of the filter is 532 nm, and the bandwidth of the filter is 10 nm.

[0029] Furthermore, the receiving telescope 20 is a reflective RC (Ritchey-Chrétien) telescope, which includes a primary mirror 22 and a secondary mirror 21. The secondary mirror 21 is arranged between the primary mirror 22 and the beam expanding optical component 12. The surface of the secondary mirror 21 facing the primary mirror 22 is a beam receiving surface. The primary mirror 22 receives the echo signal light and projects the echo signal light onto the beam receiving surface of the secondary mirror 21. The echo signal light is reflected by the beam receiving surface and then emitted from the reflective RC telescope. In summary, the reflective RC telescope is used to capture and focus the echo signal light.

[0030] Furthermore, the reflector 11 is disposed on a side of the secondary mirror 21 away from the primary mirror 22 .

[0031] In some embodiments of the present invention, along the direction perpendicular to the optical axis of the echo signal light, the size of the reflector 11 is less than or equal to the size of the secondary mirror 21, so that the reflector 11 can minimize the impact on the optical path of the echo signal light entering the primary mirror 22.

[0032] Furthermore, the laser transmitter 10 is a solid pulse laser. In some examples, the beam waist diameter of the detection laser emitted by the solid pulse laser is 8 mm, and the divergence angle of the detection laser emitted by the solid pulse laser is 3 mrad. The transceiver-integrated shipborne ocean laser radar optical system provided in the embodiment of the present invention uses a solid pulse laser as a light source to emit a high-energy short-pulse detection laser, ensuring that the detection laser has a high output energy and generating a high-energy echo signal light after scattering and reflecting with the water body to be measured.

[0033] refer to Figure 5 In some embodiments of the present invention, the beam expansion optical component 12 may be a double lens group beam expansion structure. The purpose of the beam expansion optical component 12 is to increase the beam radius when the detection laser enters the water body to be measured, and also to prevent the echo signal light from being completely blocked by the secondary mirror 21.

[0034] Furthermore, the beam radius of the detection laser after being expanded by the beam expanding optical component 12 is within the range of 30 mm to 40 mm at a distance of two meters from the beam expanding optical component 12 .

[0035] refer to Figure 2 It can be seen that the divergence angle of the detection laser after being expanded by the beam expanding optical component 12 is increased, so that the spot radius of the detection laser when it enters the water surface can be increased.

[0036] Further, the aperture of the reflecting RC telescope is 50 mm, the field angle of the reflecting RC telescope is 20 mrad, and the F number of the reflecting RC telescope is 6.5.

[0037] In some examples, after the detection laser is expanded, the beam radius of the detection laser at a distance of two meters from the expansion optical component 12 is 35 mm. In this way, in combination with the field of view and aperture of the reflective RC telescope, the echo signal light can be received without losing most of the energy of the echo signal light due to the influence of the secondary mirror 21.

[0038] It can be understood that the beam diameter of the detection laser after being expanded by the beam expanding optical component 12 is in the range of 60mm~80mm at a distance of two meters from the beam expanding optical component 12. If the beam expanding optical component 12 is set between the reflector 11 and the laser transmitter 10, then the reflector 11 is likely to exceed the aperture of the reflective RC telescope, that is, it will affect the reflective RC telescope from receiving the echo signal light. The embodiment of the present invention adopts the method of first reflecting and then expanding the beam to solve the above problem.

[0039] Further, the distance between the secondary mirror 21 and the primary mirror 22 is 43.779 mm. The distance between the secondary mirror 21 and the primary mirror 22 referred to herein refers to the distance between the center of the secondary mirror 21 and the center of the primary mirror 22.

[0040] Furthermore, the aperture of the primary mirror 22 is 50 mm, the cone coefficient of the primary mirror 22 is -1.052, the curvature radius of the primary mirror 22 is -109.400 mm, the aperture of the secondary mirror 21 is 11.060 mm, the cone coefficient of the secondary mirror 21 is -2.414, and the curvature radius of the secondary mirror 21 is 45.301 mm.

[0041] In some embodiments of the present invention, the primary mirror 22 adopts an aspherical design; the secondary mirror 21 also adopts an aspherical design.

[0042] In some embodiments of the present invention, reference Figure 5 , the beam expanding optical component 12 includes two lenses.

[0043] In some embodiments of the present invention, the optical path limiting mirror group includes three lenses, and the optical path limiting mirror group is used to limit the length of the entire optical system and the size of the receiving surface of the detector 15. The beam radius of the detection signal light converged by the optical path limiting mirror group at the focal plane of the optical path limiting mirror group is 3.662 mm.

[0044] In some embodiments of the present invention, reference Figure 4 and Figure 5 The collimating optical component 13 may include two lenses. After the detection signal light emitted from the optical path limiting lens group is collimated by the lens of the collimating optical component 13, the inclination angle of its edge light may be 0.668°.

[0045] In some embodiments of the present invention, the converging lens group 14 may include a lens. The purpose of the converging lens group 14 is to image the detection signal light within the target surface range of the detector 15 .

[0046] In some examples, the detection signal light converged by the converging lens group 14 can be focused on a target surface with a radius of 1.733 mm.

[0047] The above parameters can be used to collect echo signal light at a height of 2m from the water body to be measured. Figure 3 , it can be seen that the energy of the received detection signal light in each field of view of the detector is large, and the detection signal light collection ability is strong.

[0048] It should be noted that the integrated transceiver shipborne ocean laser radar optical system provided in the embodiment of the present invention adopts an integrated transceiver design, and the advantages of the integrated transceiver design are more significant than those of the non-integrated transceiver. Specifically, the integrated transceiver design makes the integrated transceiver shipborne ocean laser radar optical system more compact, easy to install and integrate into various application scenarios, especially in environments with limited space; the integrated design reduces the manufacturing, testing and maintenance costs, helps to reduce the number of components and the complex docking process of components, thereby reducing the optical path alignment error, which is conducive to improving measurement accuracy and reliability, and reducing wear and failure caused by connection and docking between components, and improving the overall durability and stability of the system. The system design is more concise, reduces complexity, and is easy to debug and operate; the integrated design is an integrated design, which can reduce signal transmission delay and improve the real-time performance and response speed of the system.

[0049] It should be noted that the concentration of organic matter in the water body to be tested can be inferred based on the received detection signal light, because the presence of organic matter will affect the scattering characteristics and absorption characteristics of the detection laser in the water body to be tested; it can also be used to monitor the quality of seawater, that is, by analyzing the scattering characteristics and absorption characteristics of seawater, the quality of seawater can be evaluated, and the evaluation of the quality of seawater can include evaluating the degree of pollution of seawater; it can also be used to study marine ecology. Specifically, understanding the optical properties of seawater will help study the distribution and behavior of organisms in marine ecosystems, because the distribution and activities of many marine organisms will also affect the scattering characteristics and absorption characteristics of seawater.

[0050] The present invention adopts an integrated transceiver shipborne ocean laser radar optical system to realize ocean detection, which overcomes the problem that traditional non-coaxial laser radar transmitting and receiving systems cannot fully receive signals, and also overcomes the energy loss problem caused by the beam splitter in the previous integrated transceiver.

[0051] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0052] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A shipborne marine laser radar optical system with integrated transceiver, characterized in that: include: A laser transmitter, the laser transmitter is used to emit a detection laser; A reflector and a beam expansion optical component, wherein the detection laser is reflected by the reflector and then expanded by the beam expansion optical component before entering a water body to be measured, and is scattered by the water body to be measured to form an echo signal light; a receiving telescope, the receiving telescope receiving the echo signal light and outputting a detection signal light; An optical path limiting mirror group, a collimating optical component, a converging lens group and a detector, wherein the detection signal light is sequentially subjected to the converging processing of the optical path limiting mirror, the collimating processing of the collimating optical component and the converging processing of the converging lens group and then imaged on the detector; The detection laser emitted after being reflected by the reflector is coaxial with the echo signal light.

2. The transceiver-integrated shipborne ocean laser radar optical system according to claim 1, characterized in that: The transceiver-integrated shipborne ocean laser radar optical system also includes a filter, which is arranged between the collimating optical component and the converging lens group.

3. The transceiver-integrated shipborne ocean laser radar optical system according to claim 2, characterized in that: The central wavelength of the filter is 532 nm.

4. The transceiver-integrated shipborne ocean laser radar optical system according to claim 1, characterized in that: The receiving telescope is a reflecting RC telescope, which includes a primary mirror and a secondary mirror. The secondary mirror is arranged between the primary mirror and the beam expanding optical component. The surface of the secondary mirror facing the primary mirror is a beam receiving surface. The primary mirror receives the echo signal light and projects the echo signal light onto the beam receiving surface of the secondary mirror. The echo signal light is reflected by the beam receiving surface and then emitted from the reflecting RC telescope.

5. The transceiver-integrated shipborne ocean laser radar optical system according to claim 4, characterized in that: The reflector is arranged on a side of the secondary mirror away from the primary mirror.

6. The transceiver-integrated shipborne ocean laser radar optical system according to claim 5, characterized in that: The laser emitter is a solid pulse laser, the beam waist diameter of the detection laser emitted by the solid pulse laser is 8 mm, and the divergence angle of the detection laser emitted by the solid pulse laser is 3 mrad.

7. The transceiver-integrated shipborne ocean laser radar optical system according to claim 5, characterized in that: The beam radius of the detection laser after being expanded by the beam expanding optical component is within the range of 30 mm to 40 mm at a distance of 2 meters from the beam expanding optical component.

8. The transceiver-integrated shipborne ocean laser radar optical system according to claim 4, characterized in that: The aperture of the reflecting RC telescope is 50 mm, the field of view of the reflecting RC telescope is 20 mrad, and the F number of the reflecting RC telescope is 6.

5.

9. The transceiver-integrated shipborne ocean laser radar optical system according to claim 8, characterized in that: The distance between the secondary mirror and the primary mirror is 43.779 mm.

10. The transceiver-integrated shipborne ocean laser radar optical system according to claim 8, characterized in that: The aperture of the primary mirror is 50 mm, the cone coefficient of the primary mirror is -1.052, the curvature radius of the primary mirror is -109.400 mm, the aperture of the secondary mirror is 11.060 mm, the cone coefficient of the secondary mirror is -2.414, and the curvature radius of the secondary mirror is 45.301 mm.

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