An interchangeable optical path fiber optic transmission photon ranging system and method

Abstract

The application provides an optical fiber transmission photon ranging system with interchangeable optical paths, which comprises a photon ranging machine, a first transmitting and receiving channel, a second transmitting and receiving channel, a laser emission module, a single-photon detector and a ranging processing board, wherein the optical path of the first transmitting and receiving channel / second transmitting and receiving channel is connected with the laser emission module, and the optical path of the second transmitting and receiving channel / first transmitting and receiving channel is connected with the single-photon detector; and an adjusting mechanism connected with the photon ranging machine, which is used for adjusting the photon ranging machine to a target posture. The technical scheme provided by the application can improve the teaching efficiency of the ranging system and improve the ranging precision.

Description

Technical Field

[0001] This application relates to the field of photoelectric measurement technology, specifically to an optical fiber transmission photonic ranging system and method with interchangeable optical paths. Background Technology

[0002] In modern military equipment, accurate distance measurement is crucial for efficient combat, target location, and fire control. Equipment such as vehicle commander's sights and fire control systems rely on high-precision ranging technology to ensure the rapid and accurate acquisition of target distance data in complex and dynamic battlefield environments, thereby supporting tactical decision-making and precision strikes by weapon systems. Traditional laser ranging systems typically transmit laser signals through free-space optical paths and rely on optical systems to focus the reflected laser signals, which are then fixedly received by an avalanche photodiode (APD). APDs possess high sensitivity and high-speed response, enabling them to effectively detect weak reflected signals, thus achieving high-precision distance measurement.

[0003] However, the inventors discovered that in practical applications, free-space optical paths are easily affected by external environmental interference, such as dust, smoke, and weather changes in the air, which can cause scattering and attenuation of the laser signal, thus affecting measurement accuracy. Secondly, the fixed structure of traditional optical systems and APDs makes the device calibration process relatively complex, especially in military applications where the variable and harsh combat environment requires frequent calibration and adjustment, increasing operational difficulty and time costs. Furthermore, the transmitting and receiving optical axes in traditional ranging systems are usually fixed and non-interchangeable. This not only limits the flexibility of the device but also increases the difficulty of system calibration, especially during installation, maintenance, and use, easily leading to optical axis deviation and affecting measurement accuracy. Summary of the Invention

[0004] In view of this, this application provides an optical fiber transmission photonic ranging system and method with interchangeable optical paths to solve the technical problems of low adjustment efficiency and limited ranging accuracy in the prior art.

[0005] In a first aspect, this application provides an optical fiber transmission photonic ranging system with interchangeable optical paths, the system comprising:

[0006] A photonic rangefinder, comprising a first transmit / receive channel, a second transmit / receive channel, a laser emitting module, a single-photon detector, and a ranging processing board, wherein the optical paths of the first transmit / receive channel / second transmit / receive channel are connected to the laser emitting module, and the optical paths of the second transmit / receive channel / first transmit / receive channel are connected to the single-photon detector;

[0007] An adjustment mechanism is connected to the photon rangefinder and is used to adjust the photon rangefinder to the target attitude.

[0008] Preferably, the inner end of the first transmit / receive channel is connected to a first optical splitter, the inner end of the second transmit / receive channel is connected to a second optical splitter, the laser emitting module is connected to a third optical splitter, the single-photon detector is connected to a fourth optical splitter, the first optical path of the first optical splitter is connected to the first optical path of the third optical splitter via a first optical fiber, the second optical path of the first optical splitter is connected to the first optical path of the fourth optical splitter via a second optical fiber, the first optical path of the second optical splitter is connected to the second optical path of the third optical splitter via a third optical fiber, and the second optical path of the second optical splitter is connected to the second optical path of the fourth optical splitter via a fourth optical fiber.

[0009] Preferably, a first optical path switch, a second optical path switch, a third optical path switch, and a fourth optical path switch are respectively provided on the first optical fiber, the second optical fiber, the third optical fiber, and the fourth optical fiber.

[0010] Preferably, the adjustment mechanism includes:

[0011] A fixed platform, wherein a rotating shaft is provided on the fixed platform;

[0012] A translational sliding assembly is rotatably connected to the fixed platform via the rotating shaft, and a translational sliding block is provided on the translational sliding assembly.

[0013] The rotation pitch assembly is fixedly connected at one end to the translation sliding block and at the other end to the photon rangefinder.

[0014] Preferably, the fiber optic transmission photonic ranging system with interchangeable optical paths further includes:

[0015] Temperature and humidity sensor;

[0016] The white light sight is fixedly connected to the photon rangefinder.

[0017] Secondly, this application provides an optical fiber transmission photonic ranging method with interchangeable optical paths, comprising:

[0018] The ranging mode and the target working status of the first and second transmit / receive channels are determined based on the ranging requirements.

[0019] Based on the target operating states of the first and second transceiver channels, the optical path connection / disconnection between the first and second transceiver channels and the laser emitting module, the optical path connection / disconnection between the second and second transceiver channels and the laser emitting module, the optical path connection / disconnection between the first and second transceiver channels and the single-photon detector, and the optical path connection / disconnection between the second and second transceiver channels and the single-photon detector are set.

[0020] Based on the acquired current environmental data, the laser emission intensity and detection gain parameters are adjusted to control the laser emission module to emit laser and the single-photon detector to detect laser. By combining the laser emission information and the detection information, the ranging data is calculated.

[0021] Preferably, the ranging modes include single-channel mode, single-transmit single-receive mode, single-transmit dual-receive mode, and dual-transmit single-receive mode.

[0022] Preferably, if the determined ranging mode is a single-channel mode, and if the target working state of the first transceiver channel is determined to be a dual working state, and the target working state of the second transceiver channel is a non-working state, then the optical path between the first transceiver channel and the laser emitting module is set to be connected, the optical path between the second transceiver channel and the laser emitting module is set to be disconnected, the optical path between the first transceiver channel and the single-photon detector is set to be connected, and the optical path between the second transceiver channel and the single-photon detector is set to be disconnected.

[0023] If the determined ranging mode is single-channel mode, and if the target working state of the first transmit / receive channel is determined to be non-working, and the target working state of the second transmit / receive channel is determined to be dual-working, then the optical path between the first transmit / receive channel and the laser emitting module is set to be disconnected, the optical path between the second transmit / receive channel and the laser emitting module is set to be connected, the optical path between the first transmit / receive channel and the single-photon detector is set to be disconnected, and the optical path between the second transmit / receive channel and the single-photon detector is set to be connected.

[0024] If the determined ranging mode is single transmit single receive mode, and if the target working state of the first transmit and receive channel is determined to be the transmit state and the target working state of the second transmit and receive channel is determined to be the receive state, then the optical path of the first transmit and receive channel to the laser emitter module is set to be connected, the optical path of the second transmit and receive channel to the laser emitter module is set to be disconnected, the optical path of the first transmit and receive channel to the single photon detector is set to be disconnected, and the optical path of the second transmit and receive channel to the single photon detector is set to be connected.

[0025] If the determined ranging mode is single transmit single receive mode, and if the target working state of the first transmit / receive channel is determined to be receiving state and the target working state of the second transmit / receive channel is determined to be transmitting state, then the optical path between the first transmit / receive channel and the laser emitting module is set to be disconnected, the optical path between the second transmit / receive channel and the laser emitting module is set to be connected, the optical path between the first transmit / receive channel and the single photon detector is set to be connected, and the optical path between the second transmit / receive channel and the single photon detector is set to be disconnected.

[0026] Preferably, if the determined ranging mode is a single-transmit dual-receive mode, and if the target working state of the first transmit-receive channel is determined to be a dual working state and the target working state of the second transmit-receive channel is a receiving state, then the optical path of the first transmit-receive channel to the laser emitting module is set to be connected, the optical path of the second transmit-receive channel to the laser emitting module is set to be disconnected, the optical path of the first transmit-receive channel to the single-photon detector is set to be connected, and the optical path of the second transmit-receive channel to the single-photon detector is set to be connected.

[0027] If the determined ranging mode is single-transmit dual-receive mode, and if the target working state of the first transmit-receive channel is determined to be receiving state, and the target working state of the second transmit-receive channel is determined to be dual working state, then the optical path of the first transmit-receive channel is set to be disconnected from the laser emitting module, the optical path of the second transmit-receive channel is set to be connected to the laser emitting module, the optical path of the first transmit-receive channel is set to be connected to the single-photon detector, and the optical path of the second transmit-receive channel is set to be connected to the single-photon detector.

[0028] If the determined ranging mode is dual-transmit single-receive mode, and if the target working state of the first transmit and receive channel is determined to be dual working state, and the target working state of the second transmit and receive channel is transmit state, then the optical path between the first transmit and receive channel and the laser emitter module is set to be connected, the optical path between the second transmit and receive channel and the laser emitter module is set to be connected, the optical path between the first transmit and receive channel and the single-photon detector is set to be connected, and the optical path between the second transmit and receive channel and the single-photon detector is set to be disconnected.

[0029] If the determined ranging mode is dual-transmit single-receive mode, and if the target working state of the first transmit / receive channel is determined to be the transmit state, and the target working state of the second transmit / receive channel is determined to be the dual working state, then the optical paths of the first transmit / receive channel and the laser emitter module are set to be connected, the optical paths of the second transmit / receive channel and the laser emitter module are set to be connected, the optical paths of the first transmit / receive channel and the single-photon detector are set to be disconnected, and the optical paths of the second transmit / receive channel and the single-photon detector are set to be connected.

[0030] Preferably, the process includes distance measurement axis calibration and distance measurement adjustment before distance measurement.

[0031] The ranging and axis alignment includes fixing the photon rangefinder to the axis alignment fixture, setting the optical path of the first transmitting and receiving channel to be connected with the optical path of the laser emitting module, setting the optical path of the second transmitting and receiving channel to be connected with the optical path of the laser emitting module, controlling the laser emitting module to emit laser, and adjusting the axis adjustment screw so that the laser spot emitted from the first transmitting and receiving channel and the second transmitting and receiving channel are respectively aligned with the corresponding cross-shaped center of the calibration reference.

[0032] The ranging calibration includes: presetting multiple different target distances; conducting ranging tests on all ranging modes under different environments; and determining the target threshold of laser emission intensity under different environments and the gain correction parameters for different environmental data under each test mode based on the ranging test database and a pre-trained neural network model.

[0033] The distance measurement calibration formula is:

[0034]

[0035] Where, d final The distance is calibrated, c is the speed of light, t is the round-trip time of the laser, and P is the distance. t G represents the laser intensity. r For receiver gain, I ambFor environmental noise, α represents environmental attenuation (including scattering and absorption), and d represents environmental noise. raw denoted as , where ∈ is the random error compensation value, k1 is the calibrated nonlinear error coefficient, and k2 and k3 are environmental interference compensation coefficients. k1, k2, and k3 are determined by measuring a known distance in a controllable environment and through regression fitting.

[0036] The fiber optic transmission photonic ranging technology solution with interchangeable optical paths provided in this application can effectively improve the adjustment efficiency of the ranging system and improve the ranging accuracy. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort. It should be noted that the drawings described below are illustrative and should not be construed as imposing any limitations on this application. In the drawings:

[0038] Figure 1 A schematic diagram of the structure of an optical fiber transmission photonic ranging system with interchangeable optical paths according to one embodiment of this application is shown.

[0039] Figure 2 A schematic diagram of the structure of an optical fiber transmission photonic rangefinder with interchangeable optical paths according to one embodiment of this application is shown.

[0040] Figure 3 A partial cross-sectional schematic diagram of a photonic rangefinder according to one embodiment of this application is shown;

[0041] Figure 4 A schematic diagram of a distance measurement axis alignment method according to one embodiment of this application is shown.

[0042] 1. Photon rangefinder; 11. First transmit / receive channel; 12. Second transmit / receive channel; 13. Laser emission module; 14. Single-photon detector; 15. Rangefinder processing board; 16. Temperature and humidity sensor; 17. Optical fiber; 18. FC interface; 21. Fixed platform; 22. Rotation axis; 23. Translation slider; 3. White light sight; 41. Laser spot; 42. Calibration reference; 43. Crosshair. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them.

[0044] See Figure 1 and Figure 2 This application provides an optical fiber transmission photonic ranging system with interchangeable optical paths, the system comprising:

[0045] The photon rangefinder 1 includes a first transmit / receive channel 11, a second transmit / receive channel 12, a laser emitting module 13, a single-photon detector 14, and a range processing board 15. The optical paths of the first transmit / receive channel / second transmit / receive channel are connected to the laser emitting module, and the optical paths of the second transmit / receive channel / first transmit / receive channel are connected to the single-photon detector.

[0046] The adjustment mechanism is connected to the photon rangefinder and is used to adjust the photon rangefinder to the target attitude.

[0047] Also includes: temperature and humidity sensor 16;

[0048] White light sight 3, the white light sight is fixedly connected to the photon rangefinder.

[0049] Specifically, the transmit / receive channel is connected to the laser emission module or single-photon detector via optical fiber 17, and the transmit / receive channel is connected to the optical fiber via FC interface 18.

[0050] The adjustment mechanism includes: a fixed platform 21, on which a rotating shaft 22 is provided;

[0051] The translational sliding component is rotatably connected to the fixed platform via a rotating shaft, and a translational sliding block 23 is provided on the translational sliding component; the translational sliding block can slide freely within the sliding range;

[0052] The rotation pitch component is fixedly connected at one end to the translation slider and at the other end to the photon rangefinder.

[0053] In this embodiment, the photon rangefinder can control the optical path connection between the first and second transmit / receive channels and the laser emitting module, as well as the optical path connection between the first and second transmit / receive channels and the single-photon detector, thereby enabling interchangeable transmit and receive optical axes.

[0054] It should be noted that, Figure 2The example shown depicts a method where the laser emitting module, single-photon detector, and other components are all integrated into a single housing. This application includes a configuration where the transmit and receive channels are assembled together, while the laser emitting module, single-photon detector, and other components are separately externally assembled. This method facilitates the insertion and removal of optical fibers to quickly achieve interchangeable transmit and receive optical axes. Of course, the design below, which adds a beam splitter and optical path switch, can achieve automatic control of the interchangeability of the transmit and receive optical axes, eliminating the need for manual insertion and removal. Therefore, the complete integration is the preferred implementation method, and will not be elaborated further. The highly integrated design allows the ranging system to maintain high performance while achieving miniaturization and weight reduction, making it more suitable for installation on space-constrained platforms such as military vehicles and drones, meeting the portability and mobility requirements of modern military equipment.

[0055] In this embodiment, the photon rangefinder has the function of interchangeable transmitting and receiving optical axes, which can be quickly interchanged during ranging axis calibration and ranging adjustment, avoiding disassembly and assembly during calibration and adjustment, simplifying the installation and maintenance process, reducing the difficulty of system adjustment, enabling rapid deployment and automatic adjustment, reducing the workload of operators, improving combat efficiency, and improving adjustment efficiency.

[0056] By configuring temperature and humidity sensors, the laser emission intensity and detection gain parameters can be adjusted based on the actual environmental data detected. This controls the laser emission module to emit the laser and the single-photon detector to detect it. By combining the laser emission information and the detection information, ranging data can be calculated. This reduces the need for frequent calibration in complex environments.

[0057] Transmitting laser signals via optical fiber significantly reduces signal attenuation and scattering caused by environmental factors (such as smoke, dust, and weather changes) during free-space transmission, ensuring high stability and accuracy of ranging signals in complex environments. Optical fiber is used as the transmission medium for the laser signal. The pulsed laser emitted by the laser is transmitted through the optical fiber to the transmitting channel, reaches the target, and is reflected off the target surface. The reflected light then reaches the receiving channel and is transmitted back to the receiving end through the optical fiber. This design allows for a more flexible optical path layout, avoiding the spatial limitations of fixed transmitter and receiver installation locations in traditional optics. It also effectively avoids signal attenuation and scattering problems caused by factors such as dust and humidity changes in the air, which are common in traditional intracavity transmission, ensuring stable signal transmission in complex environments.

[0058] Employing highly sensitive single-photon detectors (such as SPADs or SNSPDs), compared to traditional avalanche photodiodes, single-photon detectors can detect reflected signals at extremely low light intensities, performing exceptionally well in long-distance measurements and under low signal strength conditions. Traditional photonic rangefinders require significant laser emission energy to achieve ranging functionality, with single-pulse energy reaching mJ. In contrast, photonic ranging systems using single-photon detectors can control the single-pulse energy to the μJ level. This high-sensitivity detector, combined with fiber optic transmission technology, enables this invention to provide high-precision distance measurements even in harsh environments. Compared to traditional APD detectors, it significantly enhances the detection capability of the ranging system, especially in extremely long-distance measurements or under low signal strength conditions, ensuring high accuracy and reliability in ranging and meeting the precision measurement requirements of military applications. Featuring fiber optic transmission, interchangeable optical axes, and a highly sensitive detector, it maintains stable and reliable performance even under extreme environmental conditions, enabling it to perform ranging tasks in various complex battlefield environments and ensuring the accuracy and timeliness of operational decisions.

[0059] In practical applications, besides the aforementioned connection methods between the photon rangefinder and the structure via a rotating shaft, translational sliding assembly, and rotational pitch assembly, the adjustment mechanism can also be, for example, placed on the ground via a tripod platform. The tripod platform and the photon rangefinder are connected via a dovetail joint, enabling azimuth and pitch angle adjustments for easy aiming at the target. Similarly, the photon rangefinder and the white light sight can also be fixedly connected via a dovetail joint after high-precision alignment, which will not be elaborated further. In other words, this application does not limit the adjustment mechanism, nor its connection to the photon rangefinder or the adjustment method therein; facilitating aiming at the target is preferred.

[0060] In this application, the adjustable structure facilitates the adjustment of the azimuth and pitch angles of the photon rangefinder, making it easier to align with the target being measured, improving the installation stability and adjustment convenience of the rangefinder system, further enhancing the adjustment efficiency of the rangefinder system, and improving the rangefinder accuracy.

[0061] Preferably, the inner end of the first transmit / receive channel is connected to a first optical splitter, the inner end of the second transmit / receive channel is connected to a second optical splitter, the laser emitting module is connected to a third optical splitter, the single-photon detector is connected to a fourth optical splitter, the first optical path of the first optical splitter is connected to the first optical path of the third optical splitter via a first optical fiber, the second optical path of the first optical splitter is connected to the first optical path of the fourth optical splitter via a second optical fiber, the first optical path of the second optical splitter is connected to the second optical path of the third optical splitter via a third optical fiber, and the second optical path of the second optical splitter is connected to the second optical path of the fourth optical splitter via a fourth optical fiber.

[0062] Preferably, a first optical path switch, a second optical path switch, a third optical path switch, and a fourth optical path switch are respectively provided on the first optical fiber, the second optical fiber, the third optical fiber, and the fourth optical fiber.

[0063] In this embodiment, the optical path splitter and the optical path opening settings enable automatic control of the corresponding optical path's on / off state. This avoids the need for manual fiber optic cable insertion and removal during the switching between transmitting and receiving optical paths, allowing for a highly integrated structure of the photonic rangefinder. While maintaining high performance, this achieves miniaturization and weight reduction of the device. It is more suitable for installation on space-constrained platforms such as military vehicles and drones, meeting the portability and mobility requirements of modern military equipment.

[0064] Meanwhile, the combination of beam splitter and optical path switch allows for diverse optical path configurations and adapts to various ranging modes described later. Compared to existing fixed optical path modes or the plug-and-play method described above for interchangeable transmitting and receiving optical paths, this implementation offers a wider range of ranging methods to adapt to complex environments, while further improving the convenience of optical path interchangeability. This further enhances the adjustment efficiency and ranging accuracy of the ranging system.

[0065] It should be noted that the optical path length difference between the first and second optical fibers can be 1 meter or more, and the optical path length difference between the third and fourth optical fibers can be 1 meter or more. If the length difference is 1 meter, the time difference between the two lasers received by the single-photon detector in the single-transmit dual-receive mode and the dual-transmit single-receive mode, which are discussed later, is approximately 6.67 nanoseconds. This will not be elaborated further in the following text.

[0066] Preferably, see Figure 3 As shown, the photon rangefinder employs a double-sealed design. The outer sealing ring ensures an airtight seal, while the inner ring is a conductive sealing ring, guaranteeing electromagnetic compatibility. This further enhances its environmental adaptability, enabling stable operation in complex environments such as extreme temperatures, high humidity, and strong vibrations. By selecting materials and structural designs with strong anti-interference capabilities, the reliability of the ranging system is ensured under harsh battlefield conditions. It also possesses anti-electromagnetic interference capabilities, allowing it to operate normally in strong electromagnetic environments, meeting the high standards required by modern military equipment.

[0067] This application provides a fiber-optic photonic ranging method with interchangeable optical paths, including:

[0068] The ranging mode and the target working status of the first and second transmit / receive channels are determined based on the ranging requirements.

[0069] Based on the target operating states of the first and second transceiver channels, the optical path connection / disconnection between the first and second transceiver channels and the laser emitting module, the optical path connection / disconnection between the second and second transceiver channels and the laser emitting module, the optical path connection / disconnection between the first and second transceiver channels and the single-photon detector, and the optical path connection / disconnection between the second and second transceiver channels and the single-photon detector are set.

[0070] Based on the acquired current environmental data, the laser emission intensity and detection gain parameters are adjusted to control the laser emission module to emit laser and the single-photon detector to detect laser. By combining the laser emission information and the detection information, the ranging data is calculated.

[0071] In this embodiment, based on the target operating states of the first and second transceiver channels, the optical path connections between the first and second transceiver channels and the laser emitting module, the first and second transceiver channels and the single-photon detector, and the second transceiver channel and the single-photon detector are set. Precise control of the optical path connections ensures efficient laser emission and reception according to a predetermined mode. Based on the acquired current environmental data, the laser emission intensity and detection gain parameters are adjusted to control the laser emitting module to emit the laser and the single-photon detector to detect the laser. Combining the laser emission information and detection information, ranging data is calculated. Environmental data includes, but is not limited to, light intensity, atmospheric visibility, and temperature. Analysis of this data allows for real-time adjustment of the laser emission intensity and detection gain to adapt to different environmental conditions and ensure ranging accuracy. The system can flexibly select ranging modes and determine the operating states of the transceiver channels according to diverse ranging needs, while simultaneously adjusting operating parameters in real-time based on environmental data. This makes the system suitable for various complex ranging scenarios, including different distances, accuracy requirements, and harsh environmental conditions, greatly expanding the system's application range. By precisely controlling the optical path and adaptively adjusting to the environment, the interference of external factors on the ranging process is effectively reduced, ensuring accurate laser transmission and reception, improving the accuracy and reliability of ranging data, and meeting the application requirements of high-precision ranging. The system can quickly adjust according to needs and environmental changes without frequent manual intervention, realizing the automation and intelligence of the ranging process, greatly improving the efficiency of ranging work, and reducing labor and time costs.

[0072] Preferably, the ranging modes include single-channel mode, single-transmit single-receive mode, single-transmit dual-receive mode, and dual-transmit single-receive mode.

[0073] Preferably, if the determined ranging mode is a single-channel mode, and if the target working state of the first transceiver channel is determined to be a dual working state, and the target working state of the second transceiver channel is a non-working state, then the optical path between the first transceiver channel and the laser emitting module is set to be connected, the optical path between the second transceiver channel and the laser emitting module is set to be disconnected, the optical path between the first transceiver channel and the single-photon detector is set to be connected, and the optical path between the second transceiver channel and the single-photon detector is set to be disconnected.

[0074] If the determined ranging mode is single-channel mode, and if the target working state of the first transmit / receive channel is determined to be non-working, and the target working state of the second transmit / receive channel is determined to be dual-working, then the optical path between the first transmit / receive channel and the laser emitting module is set to be disconnected, the optical path between the second transmit / receive channel and the laser emitting module is set to be connected, the optical path between the first transmit / receive channel and the single-photon detector is set to be disconnected, and the optical path between the second transmit / receive channel and the single-photon detector is set to be connected.

[0075] If the determined ranging mode is single transmit single receive mode, and if the target working state of the first transmit and receive channel is determined to be the transmit state and the target working state of the second transmit and receive channel is determined to be the receive state, then the optical path of the first transmit and receive channel to the laser emitter module is set to be connected, the optical path of the second transmit and receive channel to the laser emitter module is set to be disconnected, the optical path of the first transmit and receive channel to the single photon detector is set to be disconnected, and the optical path of the second transmit and receive channel to the single photon detector is set to be connected.

[0076] If the determined ranging mode is single transmit single receive mode, and if the target working state of the first transmit / receive channel is determined to be receiving state and the target working state of the second transmit / receive channel is determined to be transmitting state, then the optical path between the first transmit / receive channel and the laser emitting module is set to be disconnected, the optical path between the second transmit / receive channel and the laser emitting module is set to be connected, the optical path between the first transmit / receive channel and the single photon detector is set to be connected, and the optical path between the second transmit / receive channel and the single photon detector is set to be disconnected.

[0077] Preferably, if the determined ranging mode is a single-transmit dual-receive mode, and if the target working state of the first transmit-receive channel is determined to be a dual working state and the target working state of the second transmit-receive channel is a receiving state, then the optical path of the first transmit-receive channel to the laser emitting module is set to be connected, the optical path of the second transmit-receive channel to the laser emitting module is set to be disconnected, the optical path of the first transmit-receive channel to the single-photon detector is set to be connected, and the optical path of the second transmit-receive channel to the single-photon detector is set to be connected.

[0078] If the determined ranging mode is single-transmit dual-receive mode, and if the target working state of the first transmit-receive channel is determined to be receiving state, and the target working state of the second transmit-receive channel is determined to be dual working state, then the optical path of the first transmit-receive channel is set to be disconnected from the laser emitting module, the optical path of the second transmit-receive channel is set to be connected to the laser emitting module, the optical path of the first transmit-receive channel is set to be connected to the single-photon detector, and the optical path of the second transmit-receive channel is set to be connected to the single-photon detector.

[0079] If the determined ranging mode is dual-transmit single-receive mode, and if the target working state of the first transmit and receive channel is determined to be dual working state, and the target working state of the second transmit and receive channel is transmit state, then the optical path between the first transmit and receive channel and the laser emitter module is set to be connected, the optical path between the second transmit and receive channel and the laser emitter module is set to be connected, the optical path between the first transmit and receive channel and the single-photon detector is set to be connected, and the optical path between the second transmit and receive channel and the single-photon detector is set to be disconnected.

[0080] If the determined ranging mode is dual-transmit single-receive mode, and if the target working state of the first transmit / receive channel is determined to be the transmit state, and the target working state of the second transmit / receive channel is determined to be the dual working state, then the optical paths of the first transmit / receive channel and the laser emitter module are set to be connected, the optical paths of the second transmit / receive channel and the laser emitter module are set to be connected, the optical paths of the first transmit / receive channel and the single-photon detector are set to be disconnected, and the optical paths of the second transmit / receive channel and the single-photon detector are set to be connected.

[0081] In this embodiment, the on / off state of the corresponding optical paths can be controlled automatically by controlling the first, second, third, and fourth optical path switches. The actual control logic is as follows (where 1 represents on and 0 represents off):

[0082] (1,0,1,0) — Switch 1 is on, switch 2 is off, switch 3 is on, switch 4 is off;

[0083] (0,1,0,1) — Switch 1 is off, switch 2 is on, switch 3 is off, switch 4 is on;

[0084] (1,0,0,1) — Switch 1 is on, switch 2 is off, switch 3 is off, switch 4 is on;

[0085] (0,1,1,0) — Switch 1 is off, switch 2 is on, switch 3 is on, switch 4 is off;

[0086] (1,0,1,1) — Switch 1 is on, switch 2 is off, switch 3 is on, switch 4 is on;

[0087] (0,1,1,1) — Switch 1 is off, switch 2 is on, switch 3 is on, switch 4 is on;

[0088] (1,1,1,0) — Switch 1 is on, switch 2 is on, switch 3 is on, switch 4 is off;

[0089] (1,1,0,1) — Switch 1 is on, switch 2 is on, switch 3 is off, switch 4 is on.

[0090] In this embodiment, the optical path is switched on and off automatically via a controllable optical path switch, eliminating the need for manual operation. This reduces errors and operation time caused by human intervention, improving the intelligence and efficiency of the ranging system. Simultaneously, automated control reduces the workload and skill requirements for operators. Precise optical path control logic ensures accurate connection and disconnection of the optical path under different ranging modes, enabling accurate laser emission and reception, effectively improving the accuracy and reliability of ranging, and avoiding measurement errors caused by improper optical path control.

[0091] This invention provides multiple ranging modes, allowing users to freely choose the appropriate mode based on the actual measurement scenario and requirements. For example, in close-range scenarios, a single-channel mode or a single-transmitter, single-receiver mode can be selected. It also enables rapid, high-precision measurement efficiency in close-range scenarios. For instance, in close-range scenarios, a single-transmitter, dual-receiver mode or a dual-transmitter, single-receiver mode can be selected, allowing two sets of accurate data to be obtained in a single ranging measurement. This significantly improves the detection efficiency of the ranging system, reduces the ineffective working time of components such as the laser emission module and single-photon detector, thereby reducing the overall energy consumption of the ranging system and extending the equipment's lifespan. Even if individual optical paths are damaged, ranging can still be performed normally by selecting other ranging modes or other optical paths, making the ranging system highly applicable and flexible, enabling it to be applied to more complex scenarios.

[0092] Preferably, the process includes distance measurement axis calibration and distance measurement adjustment before distance measurement.

[0093] See Figure 4 As shown, the ranging and axis alignment includes fixing the photon rangefinder to the axis alignment fixture, setting the optical path of the first transmitting and receiving channel to be connected with the optical path of the laser emitting module, setting the optical path of the second transmitting and receiving channel to be connected with the optical path of the laser emitting module, controlling the laser emitting module to emit laser, and adjusting the axis adjustment screw so that the laser spot 41 emitted from the first transmitting and receiving channel and the second transmitting and receiving channel are respectively aligned with the center of the cross-shaped 43 of the corresponding calibration reference 42.

[0094] In this embodiment, a photon rangefinder axis calibration method can be used. The photon rangefinder is fixed to the axis calibration fixture, and both channels are controlled as laser emission axes. By adjusting the axis adjustment screws, the optical axis is aligned with the centers of the two calibration reference crosshairs, thus completing the optical axis calibration. This avoids the impact of disassembly and assembly during the axis calibration process and improves the stability of the optical axis. It should be noted that if there is only one center of crosshair on the axis calibration fixture, the centers of crosshairs need to be placed in the corresponding positions one by one and the optical axis needs to be calibrated sequentially. This will not be elaborated further.

[0095] In this embodiment, two channels can be aligned simultaneously without disassembling the photon rangefinder. Existing ranging systems with non-interchangeable optical axes require disassembly, axis replacement, and subsequent installation to align the receiving axis, or the system may be manufactured with the axis aligned before assembling the rangefinder front cover, making it impossible to guarantee against the impact of disassembly and assembly. Furthermore, subsequent axis misalignment correction still requires disassembly. This application significantly improves alignment efficiency and ranging accuracy.

[0096] Preferably, the ranging calibration includes: presetting multiple different target distances; conducting ranging tests on all ranging modes under different environments; and determining the target threshold of laser emission intensity under different environments and the gain correction parameters for different environmental data under each test mode through a pre-trained neural network model based on the ranging test database.

[0097] The distance measurement calibration formula is:

[0098]

[0099] Where, d final The distance is calibrated, c is the speed of light, t is the round-trip time of the laser, and P is the distance. t G represents the laser intensity. r For receiver gain, I amb For environmental noise, α represents environmental attenuation (including scattering and absorption), and d represents environmental noise. raw denoted as , where ∈ is the random error compensation value, k1 is the calibrated nonlinear error coefficient, and k2 and k3 are environmental interference compensation coefficients. k1, k2, and k3 are determined by measuring a known distance in a controllable environment and through regression fitting.

[0100] Preferably, the ranging error d raw Based on laser intensity P t and receiver gain G r get:

[0101]

[0102] The signal transmission model, in which the laser echo power can be expressed as:

[0103]

[0104] Where is the laser emission power; ρ is the target reflectivity (0~1, the initial value can be set to 0.5); is the receiving aperture area; and / is the emission / reception optical efficiency.

[0105] Reflectance estimation calculation:

[0106]

[0107] Calibrated distance d final It is obtained by summing the following items:

[0108]

[0109] Where, Δd intensity +Δd env +Δd nonlinear +Δd temp This is to compensate for the error term.

[0110] Environmental disturbance compensation:

[0111]

[0112] Among them, I amb Ambient light intensity (measured in real time); T ambAmbient temperature; a0 is the standard atmospheric attenuation coefficient.

[0113] Temperature drift compensation:

[0114] Δd temp =k2·(T laser -T0)+k3·(T detector -T0) 2

[0115] Among them, T laser T detector This refers to the temperature of the laser emitting module and the electronic detector. The T0 reference temperature is typically 25°C.

[0116] α=α base +β1·RH+β2·PM 2.5

[0117] Where RH is relative humidity, PM 2.5 This represents the particulate matter concentration.

[0118] Laser intensity and receiver gain compensation:

[0119]

[0120] Among them, P t0 G r0 Here, k represents the reference power and gain during calibration, and k4 is the strength-delay coupling coefficient (fitted through calibration experiments).

[0121] In this embodiment, multiple different target distances are set, and the operating environment is divided into several typical types, such as sunny, cloudy, rainy, foggy, and nighttime. In each environment, ranging tests are performed on all ranging modes, recording the actual measured distance, measurement time, environmental parameters (such as light intensity, humidity, and temperature), and measurement errors, thus constructing a ranging test database. Based on this database, a pre-trained neural network model is used to determine the target threshold for laser emission intensity under different environments, as well as the gain correction parameters corresponding to different environmental data under each ranging mode, to optimize the system's ranging performance in various environments.

[0122] A pre-trained neural network model is used to perform deep analysis and learning on data in the ranging test database. The neural network model takes environmental parameters, ranging mode, and target distance as input variables, and laser emission intensity and ranging error as output variables. Through learning from a large amount of data, it uncovers the intrinsic relationship between laser emission intensity and ranging error under different environmental conditions, thereby determining the target threshold for laser emission intensity in different environments. Simultaneously, for each ranging mode, the impact of different environmental data on ranging performance is analyzed, and corresponding gain correction parameters are determined. By optimizing and adjusting the target threshold for laser emission intensity and the gain correction parameters, the ranging performance of the laser ranging system under different environments is effectively improved.

[0123] It fully considers various environmental types such as sunny days, cloudy days, rainy days, foggy days, and nighttime, as well as changes in environmental parameters such as light intensity, humidity, and temperature. Targeted parameter optimization is carried out for different environmental conditions, enabling the laser ranging system to maintain good working condition in complex and changing environments, greatly enhancing the system's environmental adaptability and broadening the application range of the laser ranging system.

[0124] Optimized laser emission intensity and gain correction parameters enable the laser ranging system to operate more stably in different environments. This reduces measurement error fluctuations caused by environmental changes, ensures the reliability and consistency of ranging results, improves the overall stability of the system, and reduces the risk of equipment failure and measurement errors.

[0125] By utilizing a constructed ranging test database and a pre-trained neural network model, data-driven intelligent parameter optimization was achieved. This method eliminates the need for complex manual judgment and adjustments, automatically uncovering potential patterns in the data, thus improving optimization efficiency and accuracy. It provides a scientific and efficient solution for enhancing the performance of laser ranging systems, further improving calibration efficiency and ranging accuracy.

[0126] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0127] While embodiments of this application have been described in conjunction with the accompanying drawings, this should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various variations or modifications based on the above description without departing from the concept of this application. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom still fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A fiber-optic transmission photonic ranging system with interchangeable optical paths, characterized in that, include: A photonic rangefinder includes a first transmit / receive channel, a second transmit / receive channel, a laser emitting module, a single-photon detector, and a ranging processing board. The optical paths of the first and second transmit / receive channels are connected to the laser emitting module, and the optical paths of the second and first transmit / receive channels are connected to the single-photon detector. The two transmit / receive channels are paired one-to-one with the laser emitting module and the single-photon detector. When any channel is connected to the laser emitting module, the other channel is simultaneously connected to the single-photon detector. An adjustment mechanism is connected to the photon rangefinder and is used to adjust the photon rangefinder to the target attitude. The inner end of the first transmit / receive channel is connected to a first optical splitter, the inner end of the second transmit / receive channel is connected to a second optical splitter, the laser emitting module is connected to a third optical splitter, the single-photon detector is connected to a fourth optical splitter, the first optical path of the first optical splitter is connected to the first optical path of the third optical splitter via a first optical fiber, the second optical path of the first optical splitter is connected to the first optical path of the fourth optical splitter via a second optical fiber, the first optical path of the second optical splitter is connected to the second optical path of the third optical splitter via a third optical fiber, and the second optical path of the second optical splitter is connected to the second optical path of the fourth optical splitter via a fourth optical fiber. The first optical fiber, the second optical fiber, the third optical fiber, and the fourth optical fiber are respectively provided with a first optical path switch, a second optical path switch, a third optical path switch, and a fourth optical path switch.

2. The fiber optic transmission photonic ranging system with interchangeable optical paths according to claim 1, characterized in that, The adjustment mechanism includes: A fixed platform, wherein a rotating shaft is provided on the fixed platform; A translational sliding component is rotatably connected to the fixed platform via the rotation shaft, and a translational sliding block is provided on the translational sliding component; The rotation pitch assembly is fixedly connected at one end to the translation sliding block and at the other end to the photon rangefinder.

3. The fiber optic transmission photonic ranging system with interchangeable optical paths according to claim 1 or 2, characterized in that, Also includes: Temperature and humidity sensor; The white light sight is fixedly connected to the photon rangefinder.

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