An airborne laser detection device for integrated underwater and overwater terrain surveying

Abstract

This invention relates to the field of radar detection technology, specifically to an airborne laser detection device for integrated surface and underwater topographic surveying. The device includes an aircraft with a radar housing mounted on it, and heat dissipation holes on the radar housing. This invention integrates a green laser depth sounding module within the radar housing. Utilizing the low absorption and high transmission characteristics of green laser light in water, it penetrates the water layer to acquire underwater three-dimensional point clouds. Simultaneously, it coordinates with an optical camera and a POS module to acquire images and attitude / position information. This allows for the simultaneous acquisition of complete spatial data on the surface, land-water boundary, and underwater topography in shallow water areas along the shoreline, overcoming the technical limitations of traditional infrared devices in water measurement. Furthermore, a data transmission terminal (DTU) serves as a central hub connecting all modules, enabling real-time, low-latency fusion of point cloud, attitude, and image data. This also simplifies cable layout and reduces system power consumption and weight.

Description

Technical Field

[0001] This invention relates to the field of radar detection technology, specifically to an airborne laser detection device for integrated underwater and surface topographic surveying. Background Technology

[0002] Current mainstream airborne terrain surveying devices generally adopt a hardware architecture that combines an infrared laser ranging module with an optical camera. This approach typically uses a drone as the aerial platform, with the optical camera and infrared laser rangefinder mounted side-by-side beneath the aircraft. In actual operation, the optical camera is responsible for acquiring multispectral image data of the land surface or water surface, while the infrared laser rangefinder utilizes the reflection characteristics of near-infrared laser light to obtain three-dimensional spatial elevation point clouds of the land surface, thereby achieving digital modeling of the landform.

[0003] While the structure of the aforementioned traditional topographic surveying device can provide a reliable measurement benchmark in terrestrial environments, it faces challenges when dealing with integrated surveying operations in water-land interface areas such as coastal intertidal zones, river and lake rise and fall zones. Near-infrared lasers have extremely high absorption rates and very weak penetration in water. When the laser beam strikes the water surface, most of the energy is directly absorbed by the water or forms specular scattering on the surface. This prevents the receiving module from capturing effective reflected echoes from the bottom, creating a data blind zone in water-bound areas and making it impossible to directly acquire underwater topographic data. Furthermore, because airborne operations require frequent traversal of near-water environments, the airflow generated by the aircraft rotor blows water mist, salt spray, and floating dust particles at high speed towards the optical window at the bottom of the infrared laser rangefinder. During continuous operation, fine droplets easily condense or salt deposits adhere to the window surface. Since lasers undergo uncontrollable refraction and scattering when penetrating different media, this not only leads to a significant attenuation of laser energy and a shortened detection depth but also causes significant ranging errors in underwater topographic modeling due to waveform distortion.

[0004] Therefore, there is an urgent need for an airborne laser detection device for integrated topographic surveying both above and below water to solve the problem that traditional surveying devices can only measure land and not water, so as to achieve seamless, high-precision integrated collaborative surveying that can measure water depth and land topography simultaneously near the shoreline. Summary of the Invention

[0005] The purpose of this invention is to provide an airborne laser detection device for integrated underwater and surface topographic surveying, in order to solve the problem that traditional topographic surveying devices cannot penetrate water when surveying the topography near the shoreline, resulting in data blind spots in water-related areas and inaccurate survey data.

[0006] To achieve the above objectives, the present invention provides the following technical solution: An airborne laser detection device for integrated surface and underwater topographic surveying includes an aircraft and a radar housing. The radar housing is fixedly installed at the lower end of the aircraft. A green laser depth sounding module and a data transmission terminal (DTU) are fixedly installed inside the radar housing. A POS module is fixedly installed at the lower end of the aircraft. An optical camera is located on the lower front side of the aircraft. The green laser depth sounding module, POS module, and optical camera are all electrically connected to the data transmission terminal (DTU). The radar housing has heat dissipation holes. A fairing is located at the bottom of the radar housing. The fairing includes a rotating part and a light-transmitting part. The rotating part is rotatably connected to the bottom of the radar housing. A rotating device is provided between the rotating part and the radar housing. The light-transmitting part is fixedly connected to the bottom of the rotating part. Multiple blades are evenly arranged on the circumference of the rotating part.

[0007] This invention integrates a green laser depth sounding module within a radar housing. Utilizing the low absorption and high transmission characteristics of the green laser band in water, it effectively penetrates the water layer and reaches underwater targets, accurately acquiring three-dimensional point cloud data of the underwater topography. Simultaneously, the device synchronously acquires high-resolution images of the land and water areas via an airborne optical camera, and uses a POS module to assign precise spatial position and attitude information to each frame of detection data. Thus, this invention can simultaneously acquire complete spatial information on the land and water topography, the land-water boundary, and the underwater topography in the shoreline and shallow water areas. This overcomes the technical limitation of traditional infrared laser devices, which can only measure land and not water, achieving seamless and high-precision collaborative operation of water depth measurement and land topography measurement along the shoreline. Furthermore, by setting a data transmission terminal (DTU) as the core data hub, this invention provides unified electrical connection and data synchronization between the green laser depth sounding module, the POS module, and the optical camera. This not only achieves real-time, low-latency fusion of water depth point cloud data, high-precision attitude and position data, and optical image data, but also simplifies the airborne cable layout and reduces system power consumption and weight.

[0008] Furthermore, by designing a light-transmitting section that rotates integrally with the rotating part at the bottom of the radar housing, and evenly distributing blades around the circumference of the cylindrical rotating part, the downdraft generated by the aircraft rotor can directly drive the rotating part to rotate the light-transmitting section at high speed. Water mist, salt spray, and dust particles adhering to the surface of the light-transmitting section are promptly thrown off under centrifugal force, thus achieving continuous self-cleaning of the optical window in a completely non-contact manner. This completely avoids the measurement blind spots and data interruptions caused by the periodic obstruction of the laser light path by the cleaning components in mechanical scraping schemes. It ensures that the green laser depth sounding radar can continuously acquire complete topographic echo signals in highly polluted environments near the water surface, significantly improving point cloud density and underwater topographic measurement accuracy. At the same time, the fairing structure formed by the blades and the rotating part cleverly transforms harmful downdraft disturbances into power to maintain window cleanliness without the need for additional independent motors and transmission mechanisms. This reduces system complexity and energy consumption, and has the advantages of compact structure, reliable operation, and maintenance-free operation. It is especially suitable for long-term, high-frequency integrated surface and underwater survey missions.

[0009] Preferably, the rotating device includes a connecting part, which is annular and fixedly connected to the rotating part. Multiple balls are evenly distributed around the circumference of the connecting part. A sliding groove is provided on the radar housing, and the multiple balls cooperate with the sliding groove. An exhaust gap is provided between the inner wall of the rotating part and the radar housing, and the width of the exhaust gap is A, where A≤2mm.

[0010] This design, by controlling the exhaust gap width between the inner wall of the rotating part and the radar housing to within 2 millimeters, creates a tiny gap while ensuring the normal rotation of the rotating part. This allows the positive pressure airflow generated by the internal cooling fan of the radar to be discharged at high speed outward along this annular exhaust gap, thus establishing a continuously ejected air curtain barrier between the rotating part and the housing. This air curtain effectively prevents external humid airflow containing water mist and salt spray from entering the radar interior through the gap due to airflow disturbance, avoiding the rotating mechanism between the rotating part and the radar housing from being affected by moisture or salt spray corrosion, which would affect the smooth operation of the rotating part. At the same time, the tiny gap width ensures unobstructed airflow between the rotating part and the radar housing, allowing the rotating mechanism to maintain its smooth operation. To maintain dryness and prevent the rotating device from becoming damp and corroded during prolonged operation in high-humidity areas, this design employs a rotating support structure with multiple circumferentially distributed ball bearings in a circular connection part that engages with the outer casing's sliding grooves. This point-contact rolling replaces the continuous surface contact of traditional bearings or bushings, ensuring smooth rotation of the rotating part while minimizing physical obstruction of the annular exhaust gap. This allows the airflow exiting the gap to be ejected outward in a complete and continuous annular air curtain shape, without breaks or turbulent dead zones, thus improving the service life of the rotating device. This design enables the rotating device to maintain a clean and dry internal air passage even in harsh near-water operating environments with high humidity and high salinity, thereby significantly improving the reliability and service life of the equipment.

[0011] Preferably, the rotating part is provided with a plurality of centrifugal sliding grooves evenly distributed around its circumference. The end of the centrifugal sliding groove near the radar housing is inclined toward the axis of the rotating part. A slider is slidably connected inside the centrifugal sliding groove. A spring is provided between the slider and the inner wall of the centrifugal sliding groove. An annular sealing strip is slidably connected to the rotating part. The annular sealing strip is fixedly connected to the plurality of sliders. One side of the annular sealing strip is in contact with the radar housing. A sealing inclined surface is provided on the annular sealing strip. The sealing inclined surface is in contact with the radar housing.

[0012] This design incorporates an annular sealing strip, fixedly connected to multiple sliders and with a width no less than the exhaust gap, which is then connected to the centrifugal sliders. When the device is not in operation, the pre-tightening force of the elastic element on the sliders tightly presses the sealing bevel on the annular sealing strip against the radar housing surface, thus reliably sealing the exhaust gap. This prevents external high-humidity, salty air and dust from flowing back into the radar housing through the gap during equipment shutdown or take-off and landing. It also prevents dust from entering the radar housing through the exhaust gap when the device is stored and not in use. Under normal operating speed, the sliders move downward along the inclined centrifugal sliding groove under centrifugal force, simultaneously dragging the annular sealing strip axially away from the housing surface, opening the exhaust gap. This allows for unobstructed release of internal heat dissipation airflow, forming a complete air curtain barrier. This achieves intelligent adaptive switching between static sealing and dynamic opening of the exhaust gap, without interfering with the air curtain protection performance during high-speed rotation, and providing additional physical isolation during non-working periods. It effectively avoids gap condensation and salt corrosion caused by frequent equipment start-ups and shutdowns or speed fluctuations, enhancing the equipment's long-term storage tolerance and operational reliability in marine salt spray and high-humidity environments.

[0013] Preferably, a thermal spring is provided inside the centrifugal sliding groove. The thermal spring is located on the side of the slider near the inside of the rectifier. One end of the thermal spring is fixedly connected to the inner wall of the centrifugal sliding groove, and the other end is in contact with the slider.

[0014] When the aircraft is operating, water mist can easily splash onto the annular sealing strip with the airflow, keeping the sealing strip constantly damp. When the aircraft stops operating, the sealing strip, before it has had time to dry, is moved back to its original position by the slider. At this point, the damp sealing strip, still carrying moisture, seals the exhaust gap, potentially contaminating the internal rotating mechanism. This design addresses this by incorporating a thermal spring inside the centrifugal sliding groove. When the aircraft starts operating and the radar begins to function, the internal temperature of the radar housing rises, causing the thermal spring to extend. When the aircraft lands and the radar stops operating, the slider, under the elastic restoring force of the spring, slides upwards along the centrifugal sliding groove to reset, simultaneously moving the annular sealing strip axially upwards. Since the radar has just stopped operating and the internal temperature has not yet decreased, the thermal spring maintains its position. In the extended state, the slider is held in place by the thermal spring during reset, preventing it from fully resetting and keeping the exhaust gap open for ventilation. Once the moisture remaining on the annular sealing strip is completely dried and the internal temperature of the radar housing decreases, the thermal spring contracts, allowing the slider to fully reset. The sealing bevel on the annular sealing strip then presses firmly against the radar housing surface, sealing the exhaust gap again. This design, through the linkage between the thermal spring and internal temperature changes, achieves a thermally controlled delay in the reset timing of the annular sealing strip. This ensures that the annular sealing strip only seals the exhaust gap after being fully dried by the internal hot airflow, preventing the damp annular sealing strip from bringing moisture into the rotating parts area and causing corrosion or salt buildup. This further enhances the durability and reliability of the equipment during long-term operation in high-humidity near-water environments.

[0015] Preferably, a wind-facing plate is provided on the outer side of the radar housing, and multiple compression blocks are provided inside the radar housing. A spring is provided between the compression block and the inner wall of the radar housing. The compression block and the corresponding wind-facing plate are fixedly connected to each other, and the compression block is in contact with the connecting part.

[0016] This design utilizes multiple interconnected wind-facing plates on the outside of the radar housing, fixedly connected to internal compression blocks. This converts the excessive downward airflow pressure generated by the aircraft propeller into mechanical compression force on the connection. During takeoff, once the propeller wind has driven the fairing to its ideal operating speed, if the wind force continues to increase, the wind-facing plates, under the influence of wind pressure, synchronously drive multiple compression blocks through connecting rods to apply radial clamping force to the connection. This creates an adaptive friction speed limiter for the rotating part, maintaining the fairing's speed within a stable and reasonable operating range across a wide range of wind variations. This prevents the rotating part from rotating too fast under strong wind conditions, causing severe vibration and operational instability. It ensures smooth rotation of the light-transmitting part and maintains a uniform and stable exhaust gap. Simultaneously, it suppresses the transmission of vibration to the inside of the radar housing, effectively preventing pointing deviations or measurement noise in the laser transmitting and receiving components due to vibration interference. This improves the detection accuracy and long-term operational reliability of the device under complex airflow conditions. Furthermore, this speed-limiting structure is entirely self-driven by wind power, requiring no additional active control components, and has the advantages of simple structure, instantaneous response, and high reliability.

[0017] Preferably, the edge of the connecting part is provided with an extrusion slope, the extrusion slope faces the top of the radar housing, an arc-shaped rod is fixedly connected to the extrusion block, and the arc center of the arc-shaped rod coincides with the arc center of the extrusion slope, and the arc-shaped rod is in contact with the extrusion slope.

[0018] By designing an arc-shaped rod on the extrusion block that aligns with the center of the arc of the extrusion ramp, and having the arc-shaped rod contact the extrusion ramp axially from above, when the windward plate is driven by strong winds to move the extrusion block downwards, the arc-shaped rod applies force evenly along the arc surface of the extrusion ramp. After the extrusion force is decomposed by the ramp, it simultaneously generates a radial friction component and a downward axial pressing component. This not only limits the rotational speed of the rotating part and prevents it from vibrating violently due to excessive speed, but also continuously applies downward pressure to the rotating part, firmly pressing it against the radar housing. This avoids axial movement that may occur during speed limiting and ensures that the exhaust gap remains uniform and stable under dynamic speed limiting conditions, further improving the stability of the fairing during high-speed operation and the reliability of the annular air curtain protection.

[0019] Preferably, the windward plate includes multiple sets of baffles, each set of baffles is symmetrical about the center of the rotating part, the area of ​​the multiple sets of baffles decreases sequentially, each baffle is connected to a corresponding extrusion block, and a limit block is provided at the bottom of the extrusion block.

[0020] This design incorporates multiple sets of baffles as the windward plates, with the windward area of ​​each set decreasing sequentially. When the aircraft blows downward airflow, all baffles are activated. However, because the spring force on each set of baffles is consistent and the windward area decreases sequentially, their displacement distance also decreases sequentially when subjected to the same airflow pressure. At this point, the compression block on the baffle with the larger windward area contacts the compression ramp first, and the displacement of the baffle is limited by the limiting block, while the pressure exerted by the compression block on the compression ramp remains constant. As the airflow gradually increases, subsequent sets of baffles sequentially contact the compression ramp and are limited, each superimposed with a constant compression force, forming a multi-stage stepped pressure output. In this way, the structure converts continuously changing airflow pressure into multi-stage and constant compression. Pressure: When the aircraft maintains a constant speed, the airflow blown out by the aircraft remains at a constant value, but there will be slight fluctuations. Coupled with the interference of the external environment, the airflow received by the wind vane will fluctuate back and forth within a certain value. Therefore, this design avoids the pressure fluctuations caused by the slight airflow fluctuations, thereby eliminating the rotational speed oscillation and braking torque pulsation caused by pressure fluctuations. This allows the fairing to maintain a stable rotational speed under different wind conditions, further suppressing the vibration and exhaust gap changes that may be caused by unstable rotational speed. This improves the operational stability and detection data consistency of the laser detection device under complex airflow conditions. Each set of baffles is symmetrical around the center of the rotating part. When the arc rod is pressed down, it can squeeze the connecting part towards the center, thereby improving the stability of the rotating part during rotation.

[0021] Preferably, a light-transmitting disk is mounted on the light-transmitting part, and the light-transmitting disk is made of quartz glass.

[0022] By installing a light-transmitting disk made of quartz glass on the light-transmitting part, the extremely high light transmittance and excellent optical uniformity of quartz glass can minimize energy loss and wavefront distortion during laser emission and reception, ensuring that the laser maintains a high-quality beam shape when penetrating the window. At the same time, due to the dense and uniform material of quartz glass, the light-transmitting disk will not produce dynamic scattering or refraction fluctuations caused by optical inhomogeneity when rotating at high speed with the rotating part. This ensures that the rotating optical window presents consistent light transmission characteristics at every moment when the laser passes through, thereby ensuring that the green laser depth sounding radar can still stably acquire distortion-free underwater echo signals while the fairing continues to rotate and centrifuge for self-cleaning, significantly improving the ranging accuracy of underwater topographic detection.

[0023] Preferably, the green laser depth measurement module is equipped with a flow guide shroud, and the flow guide shroud has an opening on the side near the light-transmitting disk.

[0024] This design, by installing a flow guide on the green laser depth sounding module and setting the side of the flow guide near the light-transmitting disk as an open structure, can directionally concentrate and guide the heat generated by the green laser depth sounding module during continuous operation. This allows the internal airflow carrying heat to be blown directly onto the inner surface of the light-transmitting disk through the opening of the flow guide, continuously heating the light-transmitting disk. As a result, the surface temperature of the light-transmitting disk is always higher than the dew point temperature of the external environment. This effectively suppresses the condensation of water vapor into fog or frost on the surface of the light-transmitting disk in high humidity environments near the water surface, ensuring that both the inner and outer sides of the light-transmitting disk remain optically dry and clean. This further guarantees the transmittance and beam quality during laser penetration and improves the detection stability and all-weather adaptability of the device under low temperature, high humidity, or drastic temperature change conditions.

[0025] Preferably, the limiting block is provided with a magnet, and the pressing block is provided with a metal sheet.

[0026] This design utilizes a magnet on the limiting block and a metal plate at the corresponding position on the extrusion block to construct a hysteresis locking mechanism with a defined threshold range by employing the force difference between the magnetic attraction and the elastic restoring force of the second spring. When the airflow is just enough to allow the extrusion block on one of the baffles to overcome the resistance of the second spring and move towards the extrusion slope, the metal plate contacts the magnet and is magnetically attracted and locked. At this point, even if the airflow changes slightly, the magnetic attraction of the magnet to the metal plate is always greater than the restoring force of the second spring, and the extrusion block remains in an attracted and locked state without rebounding. Only when the airflow weakens significantly is the spring force of the second spring sufficient to overcome the magnetic attraction and pull the extrusion block back, causing the metal plate to retract. The iron and stone separate, and to attract airflow again, the size must be increased back to the initial size. The magnets and metal sheets corresponding to the other baffles follow the same hysteresis logic. This design eliminates the vibration phenomenon caused by the squeezing blocks repeatedly contacting and separating from the squeezing slope due to the instantaneous small fluctuations in airflow under critical wind pressure. It makes the braking force output of each squeezing block to the connection part have a clear engagement and separation threshold, avoids the interference of high-frequency oscillation of the squeezing blocks near the engagement critical point on the rotational speed stability of the rotating part, and further suppresses the fairing vibration and exhaust gap fluctuation caused by the intermittent braking force. It improves the operational stability and speed limiting reliability of the laser detection device of the aircraft under turbulent or wind-changing conditions.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention integrates a green laser depth sounding module within the radar housing. Utilizing the low absorption and high transmission characteristics of green laser light in water, it penetrates the water layer to acquire underwater three-dimensional point clouds. Simultaneously, it coordinates with an optical camera and POS module to acquire images and attitude / position information. This allows for the acquisition of complete spatial data on the surface, land-water boundary, and underwater topography in shallow water areas along the shoreline, overcoming the technical blind spot of traditional infrared devices' inability to measure water. Furthermore, the data transmission terminal (DTU) serves as a hub to uniformly connect all modules, enabling real-time, low-latency fusion of point cloud, attitude, and image data. It also simplifies cable layout and reduces system power consumption and weight.

[0028] 2. This invention designs a light-transmitting part at the bottom of the radar housing that rotates integrally with the rotating part, and evenly distributes blades on the circumference of the cylindrical rotating part. This allows the downward airflow generated by the aircraft rotor to directly drive the rotating part to rotate at high speed. Water mist, salt mist, and dust particles adhering to the surface of the light-transmitting part can be promptly thrown off under centrifugal force, avoiding the problem of mechanically scraping and cleaning parts blocking the laser light path. While maintaining the cleanliness of the window, it ensures the accuracy of underwater topography measurement by the green laser depth sounding radar.

[0029] 3. By setting an exhaust gap between the inner wall of the rotating part and the radar housing, the positive pressure airflow generated by the internal cooling fan can be discharged along the annular exhaust gap, establishing a continuously outward spraying air curtain barrier. This effectively prevents the external humid airflow containing water mist and salt mist from entering the radar interior through the gap under airflow disturbance. At the same time, the exhaust gap can ensure smooth airflow and dryness of the rotating device, avoiding moisture and corrosion of the rotating device during long-term operation, and improving the service life of the rotating device. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the airborne laser detection device for integrated underwater and surface topographic surveying according to the present invention. Figure 2 This is a schematic diagram of the structure of the radar housing of the present invention; Figure 3 for Figure 2 A schematic diagram of the structure after the POS module and data transmission terminal DTU have been removed. Figure 4 This is a cross-sectional view of the radar housing of the present invention; Figure 5 for Figure 4 Enlarged view of point A in the middle; Figure 6 This is a partial cross-sectional view of the radar housing of the present invention; Figure 7 for Figure 6 A schematic diagram of the structure after further disassembly; Figure 8 for Figure 6 Enlarged view at point B in the middle; Figure 9 for Figure 7 Enlarged view of point C in the middle.

[0031] In the diagram: 1. Aircraft; 2. Radar housing; 3. Green laser depth sounding module; 4. Heat dissipation hole; 5. Fairing; 6. Rotating part; 7. Light-transmitting part; 8. Blade; 9. Exhaust gap; 10. Connecting part; 11. Ball bearing; 12. Slide groove; 13. Centrifugal sliding groove; 14. Slider; 15. Spring 1; 16. Annular sealing strip; 17. Sealing slope; 18. Windward plate; 19. Extrusion block; 20. Spring 2; 21. Baffle; 22. Arc rod; 23. Extrusion slope; 24. Light-transmitting disk; 25. Thermal spring; 26. Fairing; 27. Opening; 28. Limiting block; 29. ​​Magnet; 30. Metal sheet; 31. POS module; 32. Optical camera; 33. Data transmission terminal (DTU). Detailed Implementation

[0032] This invention provides an airborne laser detection device for integrated above-water and underwater topographic surveying, the technical solution of which is as follows: Please see Figures 1 to 9 An airborne laser detection device for integrated surface and underwater topographic surveying includes an aircraft 1 and a radar housing 2. The radar housing 2 is fixedly installed at the lower end of the aircraft 1. A green laser depth sounding module 3 and a data transmission terminal DTU 33 are fixedly installed inside the radar housing 2. A POS module 31 is fixedly installed at the lower end of the aircraft 1. An optical camera 32 is located on the lower front side of the aircraft 1. The green laser depth sounding module 3, POS module 31, and optical camera 32 are all electrically connected to the data transmission terminal DTU 33. The radar housing 2 has heat dissipation holes 4. A fairing 5 is located at the bottom of the radar housing 2. The fairing 5 includes a rotating part 6 and a light-transmitting part 7. The rotating part 6 is rotatably connected to the bottom of the radar housing 2. A rotating device is provided between the rotating part 6 and the radar housing 2. The light-transmitting part 7 is fixedly connected to the bottom of the rotating part 6. Multiple blades 8 are evenly arranged on the circumference of the side of the moving part 6. A light-transmitting disk 24 is installed on the light-transmitting part 7. The light-transmitting disk 24 is made of quartz glass. A rotating device is provided between the rotating part 6 and the radar housing 2. An exhaust gap 9 is provided between the inner wall of the rotating part 6 and the radar housing 2. The exhaust gap 9 is 2mm wide. The rotating device includes a connecting part 10. The connecting part 10 is annular and fixedly connected to the rotating part 6. Multiple balls 11 are evenly distributed on the circumference of the connecting part 10. A sliding groove 12 is provided on the radar housing 2. The multiple balls 11 cooperate with the sliding groove 12. A thermal spring 25 is provided inside the centrifugal sliding groove 13. The thermal spring 25 is located on the side of the slider 14 near the inside of the fairing 5. One end of the thermal spring 25 is fixedly connected to the inner wall of the centrifugal sliding groove 13, and the other end is in contact with the slider 14.

[0033] Please see Figures 1 to 9Multiple centrifugal sliding grooves 13 are evenly distributed around the circumference of the rotating part 6. The end of the centrifugal sliding groove 13 near the radar housing 2 is inclined toward the axis of the rotating part 6. A slider 14 is slidably connected inside the centrifugal sliding groove 13. A spring 15 is provided between the slider 14 and the inner wall of the centrifugal sliding groove 13. An annular sealing strip 16 is slidably connected to the rotating part 6. The annular sealing strip 16 is fixedly connected to the multiple sliders 14. One side of the annular sealing strip 16 is in contact with the radar housing 2. A sealing inclined surface 17 is provided on the annular sealing strip 16. The sealing inclined surface 17 is in contact with the radar housing 2.

[0034] Please see Figures 1 to 8 The radar housing 2 has a wind-facing plate 18 on its outer side and multiple extrusion blocks 19 inside. A spring 20 is installed between each extrusion block 19 and the inner wall of the radar housing 2. The extrusion blocks 19 are fixedly connected to their corresponding wind-facing plates 18. The extrusion blocks 19 contact the connecting part 10, and the edge of the connecting part 10 has an extrusion slope 23 facing the top of the radar housing 2. An arc-shaped rod 22 is fixedly connected to each extrusion block 19, and the center of the arc of the arc-shaped rod 22 coincides with the center of the arc of the extrusion slope 23. The arc-shaped rod 22 contacts the extrusion inclined surface 23. A flow guide 26 is installed on the green laser depth measurement module 3. An opening 27 is provided on the side of the flow guide 26 near the light-transmitting disk 24. The windward plate 18 includes 4 sets of baffles 21. The 4 sets of baffles 21 are symmetrical around the center of the rotating part 6. The area of ​​the 4 sets of baffles 21 decreases sequentially. Each baffle 21 is connected to the extrusion block 19 at the corresponding position. A limit block 28 is provided at the bottom of the extrusion block 19. A magnet 29 is provided on the limit block 28. A metal sheet 30 is provided on the extrusion block 19.

[0035] Please see Figures 1 to 9 Operational process of an airborne laser detection device for integrated above-water and underwater topographic surveying: I. Stopped and stationary state When the device is not in operation, the aircraft 1 is parked on the ground or platform, the propeller does not generate downdraft, and the fairing 5 is stationary. At this time, the slider 14 is located at the upper end of the centrifugal sliding groove 13 under the preload of the spring 15. The annular sealing strip 16, which is fixedly connected to the slider 14, is pressed against the surface of the radar housing 2 by the spring 15. The sealing slope 17 on the annular sealing strip 16 is tightly fitted to the radar housing 2, and the exhaust gap 9 is completely blocked. External dust, water vapor and salt spray cannot enter the interior of the radar housing 2 through the exhaust gap 9. At the same time, the wind vane 18 is not affected by the wind, and the compression block 19 is kept in a state of being detached from the connecting part 10 under the support of the spring 20, and does not exert pressure on the rotating part 6.

[0036] II. Equipment Start-up and Take-off Phase After the aircraft 1 is started, the green laser depth sounding module 3 inside the radar shell 2 is powered on and works. At the same time, the device synchronously acquires high-resolution images of the land and water areas through the airborne optical camera 32, and uses the POS module 31 to give each frame of detection data precise spatial position and attitude information. The cooling fan starts to run, forming a positive pressure airflow inside the radar shell 2. When the aircraft 1 takes off, the propeller rotates and generates a downward airflow. The airflow blows towards the blades 8 evenly distributed on the side of the rotating part 6, driving the rotating part 6 to start rotating. The rotating part 6 rotates smoothly along the slide groove 12 on the radar shell 2 through multiple balls 11 on the connecting part 10. The balls 11 achieve rotational support in a point contact manner and do not obstruct the annular exhaust gap 9.

[0037] After the rotating part 6 rotates, the light-transmitting part 7, which is fixedly connected to the bottom of the rotating part 6, rotates synchronously. The quartz glass light-transmitting disk 24 installed on the light-transmitting part 7 rotates at high speed. Water mist, salt mist and dust particles attached to the surface of the light-transmitting disk 24 are thrown off the surface under the action of centrifugal force, realizing the self-cleaning of the optical window. At the same time, the laser is emitted by the green laser depth sounding module 3, which penetrates the rotating quartz glass light-transmitting disk 24 and is directed towards the water surface. Because the quartz glass has high light transmittance and uniform material, it will not cause dynamic scattering or refraction fluctuations to the laser during the rotation. The laser maintains a high-quality beam shape to penetrate the window. The echo signal returned after being reflected by the bottom of the water also stably penetrates the light-transmitting disk 24 and is captured by the receiving component.

[0038] III. Normal Operating Status After the aircraft 1 enters a stable cruise state, the downward airflow generated by the propeller drives the rotating part 6 to rotate continuously at high speed. Under the action of centrifugal force, the slider 14 overcomes the elastic force of the spring 15 and slides downward along the centrifugal sliding groove 13. At the same time as the slider 14 slides downward, the annular sealing strip 16, which is fixedly connected to the slider 14, is synchronously dragged downward axially. The sealing slope 17 on the annular sealing strip 16 detaches from the surface of the radar housing 2, the exhaust gap 9 is opened, and the internal components of the radar housing 2 begin to work. The internal temperature of the radar housing 2 gradually rises. At this time, the thermal spring 25 extends after sensing the internal temperature of the radar housing 2, and the radar... The positive pressure airflow generated by the cooling fan inside the outer casing 2 is discharged outward at high speed along the annular exhaust gap 9, forming a complete annular air curtain barrier between the rotating part 6 and the radar outer casing 2. Since the ball bearings 11 on the connecting part 10 adopt point contact rolling support, there is no physical obstruction to the annular exhaust gap 9. The airflow can be sprayed outward in a continuous and uniform ring shape, effectively preventing the humid airflow containing water mist and salt mist from entering the radar outer casing 2 through the gap. At the same time, the dry airflow discharged outward continuously blows the connecting part 10 and the rotating device such as the ball bearings 11, keeping the rotating device in a dry state and avoiding moisture corrosion in a high humidity environment.

[0039] IV. Adaptive speed limiting under strong wind conditions When the aircraft 1 encounters strong winds or its flight speed increases, causing a significant increase in the downward wind pressure generated by the propeller, if the wind force continues to increase, the rotating part 6 may rotate too fast and produce violent vibrations. At this time, the windward plate 18 located on the outside of the radar housing 2 is subjected to the increased wind pressure, which drives the fixedly connected compression block 19 to move downward against the elastic force of the spring 20. The arc-shaped rod 22 on the compression block 19 applies force evenly along the arc-shaped surface of the compression slope 23 at the edge of the connecting part 10. Since the center of the arc of the arc rod 22 coincides with the center of the arc of the compression slope 23, the compression force is decomposed into radial friction through the compression slope 23. The friction force, downward axial pressing force, and radial friction force act as a brake on the connecting part 10, limiting the rotational speed of the rotating part 6 from further increasing and preventing severe vibration and operational instability caused by excessive speed. The downward axial pressing force continuously presses the rotating part 6 downward against the radar housing 2, preventing axial movement during speed limiting and ensuring that the exhaust gap 9 remains uniform and stable under dynamic speed limiting conditions. When the wind force weakens, the compression block 19 resets under the elastic restoring force of the second spring 20, the pressure of the arc rod 22 on the compression slope 23 decreases or is released, and the rotating part 6 returns to its normal speed range. The entire process relies entirely on wind power for self-adaptive adjustment, without the intervention of any active control components.

[0040] V. Landing and Parking Phase When aircraft 1 prepares to land, the propeller speed decreases, the airflow gradually weakens, the wind drive on blade 8 decreases, and the speed of rotating part 6 decreases accordingly. When the speed drops below the critical value where centrifugal force and spring-15 elastic force are balanced, slider 14 slides upward and resets along centrifugal sliding groove 13 under the action of spring-15 elastic restoring force, simultaneously driving the annular sealing strip 16 to move upward axially. At this time, since the internal components of radar housing 2 have just stopped working, the internal temperature has not yet dropped, and thermal spring 25 remains extended. When slider 14 resets, it will be blocked by thermal spring 25, preventing slider 14 from fully resetting. The exhaust gap 9 is still open to maintain ventilation. When the annular sealing strip 16... After the remaining moisture is completely dried and the internal temperature of the radar housing 2 decreases, the thermal spring 25 contracts, allowing the slider 14 to fully reset. The sealing slope 17 on the annular sealing strip 16 is then pressed tightly against the surface of the radar housing 2, and the exhaust gap 9 is sealed again. At the same time, the wind pressure on the wind vane 18 disappears, the compression block 19 resets under the action of the second spring 20, and the pressure of the arc rod 22 on the compression slope 23 is completely released. After the aircraft 1 lands, the propeller stops running, the rotating part 6 is completely stationary, and the annular sealing strip 16 maintains a static seal on the exhaust gap 9 to prevent external dust, moisture, and salt spray from entering the radar housing 2. The device returns to a stopped and stationary state, waiting for the next mission to start.

[0041] The specific embodiment of the present invention has been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the embodiments described above. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and ideas of the present invention should still fall within the protection scope of the present invention.

Claims

1. An airborne laser detection device for integrated surface and underwater topographic surveying, comprising an aircraft (1) and a radar housing (2), wherein the radar housing (2) is fixedly installed at the lower end of the aircraft (1), characterized in that, A green laser depth sounding module (3) and a data transmission terminal DTU (33) are fixedly installed inside the radar housing (2). A POS module (31) is fixedly installed at the lower end of the aircraft (1). An optical camera (32) is provided on the lower front side of the aircraft (1). The green laser depth sounding module (3), the POS module (31), and the optical camera (32) are all electrically connected to the data transmission terminal DTU (33). A heat dissipation hole (4) is provided on the radar housing (2). A fairing (5) is provided at the bottom of the radar housing (2). The fairing (5) includes a rotating part (6) and a light-transmitting part (7). The rotating part (6) is rotatably connected to the bottom of the radar housing (2). A rotating device is provided between the rotating part (6) and the radar housing (2). The light-transmitting part (7) is fixedly connected to the bottom of the rotating part (6). Multiple blades (8) are evenly arranged on the circumference of the rotating part (6).

2. The airborne laser detection device for integrated surface and underwater topographic surveying according to claim 1, characterized in that, The rotating device includes a connecting part (10), which is annular and fixedly connected to the rotating part (6). Multiple balls (11) are evenly distributed around the circumference of the connecting part (10). A sliding groove (12) is provided on the radar housing (2). The multiple balls (11) cooperate with each other with the sliding groove (12). An exhaust gap (9) is provided between the inner wall of the rotating part (6) and the radar housing (2). The width of the exhaust gap (9) is A, where A≤2mm.

3. The airborne laser detection device for integrated surface and underwater topographic surveying according to claim 2, characterized in that, Multiple centrifugal sliding grooves (13) are evenly distributed around the circumference of the rotating part (6). The end of the centrifugal sliding groove (13) near the radar housing (2) is inclined toward the axis of the rotating part (6). A slider (14) is slidably connected inside the centrifugal sliding groove (13). A spring (15) is provided between the slider (14) and the inner wall of the centrifugal sliding groove (13). An annular sealing strip (16) is slidably connected on the rotating part (6). The annular sealing strip (16) is fixedly connected to multiple sliders (14). One side of the annular sealing strip (16) is in contact with the radar housing (2). A sealing inclined surface (17) is provided on the annular sealing strip (16). The sealing inclined surface (17) is in contact with the radar housing (2).

4. The airborne laser detection device for integrated surface and underwater topographic surveying according to claim 3, characterized in that, A thermal spring (25) is provided inside the centrifugal sliding groove (13). The thermal spring (25) is located on the side of the slider (14) near the inside of the shroud (5). One end of the thermal spring (25) is fixedly connected to the inner wall of the centrifugal sliding groove (13), and the other end is in contact with the slider (14).

5. The airborne laser detection device for integrated surface and underwater topographic surveying according to claim 4, characterized in that, The radar housing (2) is provided with a wind-facing plate (18) on the outside and multiple extrusion blocks (19) are provided inside the radar housing (2). A spring (20) is provided between the extrusion block (19) and the inner wall of the radar housing (2). The extrusion block (19) is fixedly connected to the corresponding wind-facing plate (18) and the extrusion block (19) is in contact with the connecting part (10).

6. The airborne laser detection device for integrated surface and underwater topographic surveying according to claim 5, characterized in that, The edge of the connecting part (10) is provided with an extrusion slope (23), the extrusion slope (23) faces the top of the radar housing (2), an arc rod (22) is fixedly connected to the extrusion block (19), and the arc center of the arc rod (22) is consistent with the arc center of the extrusion slope (23), and the arc rod (22) is in contact with the extrusion slope (23).

7. The airborne laser detection device for integrated surface and underwater topographic surveying according to claim 6, characterized in that, The windward plate (18) includes multiple sets of baffles (21). Each set of baffles (21) is symmetrical about the center of the rotating part (6). The area of ​​the multiple sets of baffles (21) decreases sequentially. Each baffle (21) is connected to a corresponding extrusion block (19). A limit block (28) is provided at the bottom of the extrusion block (19).

8. The airborne laser detection device for integrated surface and underwater topographic surveying according to claim 7, characterized in that, A light-transmitting disc (24) is installed on the light-transmitting part (7), and the light-transmitting disc (24) is made of quartz glass.

9. The airborne laser detection device for integrated surface and underwater topographic surveying according to claim 8, characterized in that, The green laser depth measurement module (3) is equipped with a flow guide (26), and the flow guide (26) has an opening (27) on the side near the light-transmitting disk (24).

10. The airborne laser detection device for integrated surface and underwater topographic surveying according to claim 7, characterized in that, The limiting block (28) is provided with a magnet (29), and the pressing block (19) is provided with a metal sheet (30).

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