Non-coaxial laser warning method

Abstract

The present application belongs to the technical field of photoelectric detection, and particularly relates to a non-coaxial laser warning method, which comprises the following steps: S1: calculating the laser power of the effect signal reflected by the effect module and received by the effect tracking module in a real application scenario by using a small target radar equation; S2: constructing an equivalent scaling equation to calculate the laser power of the coded laser signal emitted by the emitting module; S3: adjusting the laser power of the coded laser signal emitted by the emitting module in the equivalent scaling scenario; S4: making the effect image collected by the effect tracking module a clear image in the equivalent scaling scenario; and S5: deploying no less than two effects in a real application scenario, and positioning the three-dimensional space coordinates of the laser source according to the type of the effects. The present application builds an automatic tracking and sighting system, designs an equivalent scaling experiment, and realizes the non-coaxial laser warning scheme of laser link tracking through the imaging and detection analysis of the effects.

Description

Technical Field

[0001] This invention belongs to the field of photoelectric detection technology, and particularly relates to a non-coaxial laser alarm method. Background Technology

[0002] With the rapid development and application of laser technology, laser warning systems play a crucial role in identifying and locating laser beam links. Generally, laser warning devices are mainly used to detect enemy laser illumination and issue early warnings. They can analyze information such as the wavelength, power, direction, and encoding of the laser link, providing alerts to facilitate appropriate measures. Currently, however, laser warning devices are primarily used to warn of direct threats to onboard systems from laser ranging beams, laser weapons, and laser-guided systems, aiming to enhance the survivability of the warning unit—essentially for defense. With the increasing widespread application of laser communication technology in space and airspace, the concept of laser early warning can be extended to the early warning and location of enemy communication beam links, potentially giving us the initiative and even paving the way for deeper information interception.

[0003] Currently, laser alarm technology can be categorized into four types based on its detection principle: coherent recognition, spectral recognition, grating diffraction, and imaging. Traditional laser alarm methods, such as coherent recognition, spectral recognition, grating diffraction, and imaging laser alarms, all suffer from disadvantages including high value (requiring multiple parallel dedicated high-value alarm units), large size (including the carrier), and ease of detection and locking. Since the activation of a laser alarm typically indicates that our unit has been locked by the laser link, existing solutions are all coaxial, limiting the application of such laser alarms to high-intensity confrontation scenarios. Summary of the Invention

[0004] In view of this, the present invention aims to provide a non-coaxial laser alarm method. In order to reduce the deployment cost of laser alarm devices and to address the positioning and analysis requirements of laser beam links in different scenarios, this invention solves the problem of laser alarms that can be both coaxial and non-coaxial. The present invention builds an automatic tracking and aiming system, designs an equivalent scaled-down experiment, and realizes a non-coaxial laser alarm scheme for laser link tracking by imaging and detection analysis of the effector.

[0005] To achieve the above objectives, the technical solution created by this invention is implemented as follows:

[0006] A non-coaxial laser alarm method specifically includes the following steps:

[0007] S1: Build a non-coaxial laser alarm system including a transmitting module, an effector tracking module, an effector module and a laser source tracking module, preset the calculation parameters of the real application scenario, and use the small target radar equation to calculate the laser power of the effector tracking module receiving the effector signal reflected by the effector module in the real application scenario.

[0008] S2: Construct an equivalent scaling equation. Preset the distance between the effect tracking module and the effect module in the equivalent scaling scenario. Substitute the calculation result of step S1 into the equivalent scaling equation to calculate the laser power of the coded laser signal emitted by the transmitting module.

[0009] S3: Adjust the laser power of the coded laser signal emitted by the transmitting module in the equivalent scale scenario so that the laser power of the effect object tracking module receiving the effect object signal reflected by the effect object module in the equivalent scale scenario is within a preset range.

[0010] S4: In the equivalent scale scenario, the effect object tracking module is used to acquire the effect object image of the effect object module. If the effect object image acquired by the effect object tracking module is a clear image, then step S5 is executed; otherwise, step S3 is executed until the effect object image acquired by the effect object tracking module is a clear image.

[0011] S5: In real-world application scenarios, deploy no fewer than two effectors, use a non-coaxial laser alarm system to capture effector information, and locate the three-dimensional spatial coordinates of the laser source based on the type of effector.

[0012] Furthermore, the non-coaxial laser alarm system also includes a gyroscope inertial navigation module and an optoelectronic detection module. The effect object tracking module, laser source tracking module, gyroscope inertial navigation module, and optoelectronic detection module are all mounted on the automatic tracking vehicle.

[0013] The transmitting module is used to emit coded laser signals;

[0014] The effector module is used to hold the effector, which receives and modulates the encoded laser signal to obtain the effector signal;

[0015] The effect object tracking module is used to capture effect object signals, so that the effect object is clearly imaged at the center of the field of view of the camera that is equipped with the effect object tracking module, and obtains the three-dimensional spatial coordinates of the effect object by constructing a three-dimensional spatial reference coordinate system.

[0016] The laser source tracking module is used to scan the light field along the laser incident direction. It uses a camera to capture the strong scattering signal of the laser source exit lens group and combines it with a three-dimensional spatial reference coordinate system to realize the three-dimensional spatial coordinate measurement of the laser source.

[0017] The gyroscope inertial navigation module is used to monitor the rotation angle and current pose changes of the automatic tracking vehicle in real time, and to perform real-time compensation on the three-dimensional spatial reference coordinate system based on the monitoring results.

[0018] The photoelectric detection module is used to receive coded laser signals, convert them into electrical signals, and perform filtering, demodulation, and waveform analysis on the electrical signals to intercept and decipher the modulation and coding information in the coded laser signals.

[0019] Furthermore, let the geometric center of the effect object be C, and the three-dimensional spatial reference coordinate system take the geometric center of the automatic tracking vehicle as the origin O, take the line connecting OC as the Z-axis, take the horizontal direction of the field of view of the effect object tracking module's camera as the X-axis, and take the vertical direction of the field of view of the effect object tracking module's camera as the Y-axis to construct the three-dimensional spatial reference coordinate system.

[0020] Furthermore, the effect module includes a fixture, a carrier, and an effect. The fixture holds the carrier, the carrier carries the effect, and the back of the effect is attached to the carrier via fine cotton threads in three directions. The fixture and the carrier are anodized and darkened, and the fine cotton threads are coated with a highly conductive paste.

[0021] Furthermore, the effector is a fabric made of a blend of metal wires and polymer fibers or a mirror-reflective spherical shell.

[0022] Furthermore, in step S1, the small target radar equation is:

[0023] ;

[0024] in, P 0 represents the emission power of the laser link beam. P r The laser power of the effector signal received by the effector tracking module. i Tx The beam divergence angle, D The distance between the transmitting module and the effector. or 1 and or 2 represents the transmittance of the laser emitter's optical system and the transmission process, respectively. D r This represents the distance between the effector tracking module and the corresponding effector module in a real-world application scenario. r h The reflectance of the effector A r The effective scattering area of ​​the effector A c The area of ​​light received by the effector tracking module. oh r The diffraction solid angle of the effector is denoted as .

[0025] Furthermore, in step S2, the expression for the equivalent scaling equation is:

[0026] ;

[0027] in, P t The laser power of the encoded laser signal emitted by the transmitting module. S B To encode the cross-sectional area of ​​the laser beam on the effector, r h The reflectance of the effector R d The distance between the effect tracking module and the effect module in an equivalent scaled-down scenario. or This is the transmittance correction factor. A r The effective scattering area of ​​the effector A c The area of ​​light received by the photoelectric detection module. oh r The diffraction solid angle of the effector is denoted as .

[0028] Furthermore, if the effector is a specularly reflecting spherical shell, the specularly reflecting spherical shell is fixed to the effector module. The effector tracking module then performs a clear imaging of the specularly reflecting spherical shell to obtain an image of it. The distance between the specularly reflecting spherical shell and the effector tracking module is obtained using the rangefinder of the effector tracking module. Let the image diameter of the specularly reflecting spherical shell in the image be... D im 1 pixel;

[0029] Calculate the pixel offset (Δ) of the peak grayscale point of the specular reflective spherical shell relative to the image center of the specular reflective spherical shell. x ,Δ y );

[0030] A local coordinate system is constructed with the geometric center of the specularly reflecting spherical shell as the origin. The normalized offset is calculated, and the coordinates of the reflection point on the specularly reflecting spherical shell in the image are determined in the local coordinate system based on the normalized offset. s x , s y , s z The process includes the following formula:

[0031] ;

[0032] ;

[0033] Map the coordinates of the reflection point on the mirrored spherical shell in the image of the mirrored spherical shell back to the real application scenario to obtain the coordinates of the reflection point on the mirrored spherical shell in the three-dimensional reference coordinate system.

[0034] Obtain the normal vector and reflection vector of the reflecting surface of the specular reflective spherical shell, and set the normal vector of the reflecting surface of the specular reflective spherical shell as... Let the reflection vector of the specular reflective spherical shell be set as Calculate the unit vector of the laser incident direction. :

[0035] = S - C ;

[0036] ;

[0037] ;

[0038] in, S Let C be the coordinates of the reflection point on the mirror-reflecting spherical shell in the three-dimensional reference coordinate system, and let C be the coordinates of the geometric center of the effect object in the three-dimensional reference coordinate system.

[0039] Furthermore, in step S5, if the effector is a mirror-reflecting spherical shell, the three-dimensional spatial coordinates of the laser source are obtained by using single-frame single-target localization, single-frame multi-target localization, or multi-frame multi-target localization; if the effector is a fabric made of metal wire and polymer fiber blend, the three-dimensional spatial coordinates of the laser source are obtained by using single-frame multi-target localization or multi-frame multi-target localization.

[0040] The specific method for obtaining the three-dimensional spatial coordinates of the laser source using single-frame single-target localization is as follows: the laser source tracking module rotates and scans around the Y-axis in the opposite direction of the unit vector of the laser incident direction until the laser source appears in the field of view of the laser source tracking module. The three-dimensional spatial coordinates of the laser source in the three-dimensional spatial reference coordinate system are obtained by the rotation angle and the ranging results.

[0041] Furthermore, in step S5, obtaining the three-dimensional spatial coordinates of the laser source using single-frame multi-target localization or multi-frame multi-target localization specifically includes the following steps:

[0042] S51: Acquire effector images, and take effectors with effector signals as valid effectors. If the effector tracking module only acquires a single frame effector image containing no less than two valid effectors, then execute step S52. If the effector tracking module acquires multiple frames effector images containing no less than two valid effectors, then execute step S53.

[0043] Step S52 includes: taking the three-dimensional spatial coordinates of any two effective effectors in the three-dimensional reference coordinate system, and calculating the laser direction vector using the following formula:

[0044] ;

[0045] in, and These are the three-dimensional spatial coordinates of the two effective effectors. The laser direction vector;

[0046] The laser direction vector is aligned with the normal vector of the effect object plane to obtain the final laser direction vector. The laser source tracking module is rotated around the z-axis of the three-dimensional spatial reference coordinate system so that the projection of the final laser direction vector onto the XOY plane of the three-dimensional spatial reference coordinate system coincides with the X-axis. The laser source tracking module then rotates and scans around the Y-axis in the opposite direction of the final laser direction vector until the laser source appears in the field of view of the laser source tracking module. The three-dimensional spatial coordinates of the laser source in the three-dimensional spatial reference coordinate system are obtained through the rotation angle and ranging results.

[0047] Step S53 includes: taking the three-dimensional spatial coordinates of any two effective effect objects in any two frames of effect object images, and calculating the tracking vector of the corresponding effect object image using the following formula:

[0048] ;

[0049] ;

[0050] in, Let be the tracing vector formed by two effective effectors in the effector image of the m-th frame. Let be the tracing vector formed by two effective effectors in the nth frame effector image. and Let be the three-dimensional spatial coordinates of the two effective effectors in the m-th frame effector image. and Let be the three-dimensional spatial coordinates of the two effective effectors in the nth frame of the effector image;

[0051] The tracking vector is calculated using the following formula. and tracking vector All perpendicular normal vectors :

[0052] ;

[0053] in, For the tracking vector and tracking vector All perpendicular normal vectors;

[0054] make ∈ Solving for the tracing vector The corresponding spatial line and tracing vector The common perpendicular of the corresponding spatial lines, and the common perpendicular and the tracking vector. The intersection of the corresponding spatial lines serves as the position approximation point for the effect image in the m-th frame. The common perpendicular and the tracking vector The intersection of the corresponding spatial lines serves as the position approximation point for the effect image in the nth frame. The approximation point is calculated using the following formula. and location proximity point Three-dimensional spatial coordinates:

[0055] ;

[0056] Approach the location and location proximity point The three-dimensional spatial coordinates of the midpoint of the line connecting the two points are used as the three-dimensional spatial coordinates of the laser source.

[0057] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0058] This invention presents a non-coaxial laser warning method that addresses the positioning and analysis requirements of laser beam links in various scenarios, solving the challenge of laser warning that can be implemented in both coaxial and non-coaxial configurations, while simultaneously reducing the deployment cost of laser warning devices. This invention designs diverse and low-cost effector schemes for different scenarios, such as ground-to-air, sea-to-air, and extraterrestrial environments, and provides corresponding methods for laser source positioning, warning, and information interception. Furthermore, since the effector and photoelectric detection equipment used in this invention are separate, most of the laser warning functions can be achieved without the need for dedicated instruments such as laser warning devices, saving the vehicle corresponding payload space, cost, and weight burden. Simultaneously, due to its non-coaxial warning function, this invention can also provide more reaction time for the vehicle to perform evasive maneuvers after receiving a strong warning signal, or function as a decoy. Attached Figure Description

[0059] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0060] Figure 1 A schematic flowchart of the non-coaxial laser alarm method described in the embodiments of the present invention;

[0061] Figure 2A schematic diagram of the Archimedean spiral scanning mode as described in the embodiments of the present invention;

[0062] Figure 3 Images of the effector described in the embodiments of the present invention;

[0063] Figure 3 (a) An image of the effect object under strong light illumination as described in the embodiments of the present invention;

[0064] Figure 3 (b) An image of the effect object under low-light illumination as described in the embodiments of the present invention;

[0065] Figure 4 A schematic diagram of the structure of the effector module described in the embodiment of the present invention;

[0066] Figure 5 A schematic diagram illustrating the process of using a mirror-reflecting spherical shell to locate the laser incident direction as described in an embodiment of the present invention;

[0067] Figure 5 (a) A schematic diagram of the modulation optical path according to an embodiment of the present invention;

[0068] Figure 5 (b) is a schematic diagram of solving the coordinates of the reflection point according to an embodiment of the present invention.

[0069] Explanation of reference numerals in the attached figures:

[0070] 1. Effector; 2. Fine thread; 3. Carrier. Detailed Implementation

[0071] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0072] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0073] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0074] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0075] In order to enable the laser warning system to have certain concealment characteristics and to be applied in diverse scenarios such as laser countermeasures warning, laser communication link interception, laser guidance warning, and laser ranging warning, the light field control device (in this invention, the effector module) is placed externally in a specific area to achieve the separation of light field control, detection, and decoding functions.

[0076] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0077] like Figure 1 As shown, the present invention provides a non-coaxial laser alarm method, which specifically includes the following steps:

[0078] S1: Build a non-coaxial laser alarm system including a transmitting module, an effector tracking module, an effector module and a laser source tracking module, preset the calculation parameters of the real application scenario, and use the small target radar equation to calculate the laser power of the effector tracking module receiving the effector signal reflected by the effector module in the real application scenario.

[0079] S2: Construct an equivalent scaling equation. Preset the distance between the effect tracking module and the effect module in the equivalent scaling scenario. Substitute the calculation result of step S1 into the equivalent scaling equation to calculate the laser power of the coded laser signal emitted by the transmitting module.

[0080] S3: Adjust the laser power of the coded laser signal emitted by the transmitting module in the equivalent scale scenario so that the laser power of the effect object tracking module receiving the effect object signal reflected by the effect object module in the equivalent scale scenario is within a preset range.

[0081] S4: In the equivalent scale scenario, the effect object tracking module is used to acquire the effect object image of the effect object module. If the effect object image acquired by the effect object tracking module is a clear image, then step S5 is executed; otherwise, step S3 is executed until the effect object image acquired by the effect object tracking module is a clear image.

[0082] S5: In real-world application scenarios, deploy no fewer than two effect objects 1, use a non-coaxial laser alarm system to capture effect object information (including effect object images and effect object signals), and locate the three-dimensional spatial coordinates of the laser source according to the type of effect object 1.

[0083] It should be noted that this invention focuses on more covert combat scenarios. It utilizes a low-cost grating diffraction-type light field manipulation device deployed externally, and an onboard imaging device to analyze the wavefront of the light field manipulation device, thereby analyzing and locating the beam path passing through the device. Furthermore, this invention provides a method for establishing an equivalent scaled-down model for specific scenarios, which can be used to calibrate and inversely deduce parameters such as the direction, wavelength, and power of the laser link.

[0084] This invention, based on the modulation and dispersion characteristics of incident spatial light using grating diffraction-type optical field modulators, employs grating diffraction-type optical field modulators of different shapes. It utilizes the modulation wavefront characteristics of the optical field modulator (referring to the effector module of this invention) to deduce the positioning and wavelength information of the laser link irradiated onto the optical field modulator. Furthermore, this invention may also use the above information to further decode the laser link information, or facilitate closer approach and interception of more detailed information.

[0085] This invention employs a non-coaxial laser alarm scheme, primarily used to expose and alarm non-friendly laser links, thereby facilitating the acquisition of link information or assisting other units in alerting them of potential laser threats. The term "non-coaxial" refers to the optical field modulation device (effect 1) used to modulate the laser link's optical signal being placed at a distance from the photodetector (i.e., the sensing alarm unit). The photodetector observes the optical field modulation device and analyzes the modulated optical field information to obtain information about the laser link.

[0086] In this system, the geometric center of the effect object is denoted as C. A three-dimensional spatial reference coordinate system is established with the geometric center of the automatic tracking vehicle as its origin O. The line connecting OC is used as the Z-axis, the horizontal direction of the field of view of the camera accompanying the effect object tracking module is used as the X-axis, and the vertical direction of the field of view of the camera accompanying the effect object tracking module is used as the Y-axis. The effect object tracking module acquires images of the staring optical field modulator through the accompanying camera. First, it uses information such as the attitude of effect object 1, the position of the imaging grayscale peak, or the specific optical field mode modulated and detected to solve for the normal vector. Then, based on the mapping relationship between the imaging effect and even the optical field mode of the optical field modulator under different laser incident angles, it inversely deduces the laser incident vector and wavelength, thereby locating the laser link. When the same frame of acquired images contains more than two effect objects 1, the laser incident vector information can be further verified, accelerating the scanning and positioning speed of the laser source.

[0087] The non-coaxial laser warning system also includes a gyroscope inertial navigation module and an optoelectronic detection module. Furthermore, the effect object tracking module, laser source tracking module, gyroscope inertial navigation module, and optoelectronic detection module are all mounted on the automatic tracking vehicle.

[0088] The transmitting module is used to emit coded laser signals;

[0089] The effector module is used to hold effector 1. Effector 1 receives and modulates the encoded laser signal to obtain the effector signal.

[0090] The effect object tracking module is used to capture effect object signals, so that effect object 1 is clearly imaged at the center of the field of view of the camera that is equipped with the effect object tracking module, and obtains the three-dimensional spatial coordinates of effect object 1 by constructing a three-dimensional spatial reference coordinate system.

[0091] The laser source tracking module is used to scan the light field along the laser incident direction. It uses a camera to capture the strong scattering signal of the laser source exit lens group and combines it with a three-dimensional spatial reference coordinate system to realize the three-dimensional spatial coordinate measurement of the laser source.

[0092] The gyroscope inertial navigation module is used to monitor the rotation angle and current pose changes of the automatic tracking vehicle in real time, and to perform real-time compensation on the three-dimensional spatial reference coordinate system based on the monitoring results.

[0093] The photoelectric detection module is used to receive coded laser signals, convert them into electrical signals, and perform filtering, demodulation, and waveform analysis on the electrical signals to intercept and decipher the modulation and coding information in the coded laser signals.

[0094] It should be noted that all optical components of the transmitting module are fixed and integrated onto a breadboard using fork-type clamps and sleeves. A Φ50.8, f75mm near-infrared lens is installed in the optical path of the transmitting module. Its purpose is to reduce the beam divergence angle as much as possible when using fiber optic output, where beam quality is very poor, by lowering the F-number (F-number is also known as lens speed; a smaller F-number indicates a faster lens speed). Additionally, a foldable power meter probe is mounted behind all optical components of the transmitting module to monitor the energy of the emitted laser at any time. The light source modulation device used in this invention (distinct from light field modulation; this device simulates laser beam encoding in scenarios such as laser communication, laser guidance, and laser ranging) is an optical chopper. It uses a PID-controlled motor and code disk to modulate a continuous beam, providing a maximum chopping frequency of 3000 Hz. To make the chopping frequency more stable, approximately 2 / 3 of the highest frequency is empirically selected; that is, a chopping frequency of 2000 Hz was used in the actual experiment, and the frequency drift rate measured with an oscilloscope was less than 0.2%.

[0095] Furthermore, after the laser is started, the power meter monitors the energy of the emitted laser in real time, the near-infrared lens optimizes the beam propagation characteristics synchronously, and the optical chopper modulates the continuous beam with optimized beam propagation characteristics to simulate laser beam encoding in scenarios such as laser ranging, guidance, and communication, and finally completes the transmission and output of the laser signal.

[0096] Regarding the setup of the effector module, since effector 1 itself has high reflectivity, and the clamping device is required to have relatively low reflectivity, the surface of the clamping device must be treated. Generally, anodizing is used to darken the fixture and carrier 3. However, to ensure that the reflectivity around effector 1 is sufficiently low, such as... Figure 4 As shown, in this invention, fine threads 2 are attached to the back of the effect object 1 in three directions, and a 10% mass fraction of highly conductive pure graphene / carbon nanotube composite slurry is used to coat the fine threads multiple times, thereby ensuring that the background noise signal around the effect object 1 will not affect the imaging of the effect object 1.

[0097] Furthermore, based on the application scenario (such as near-infrared laser link tracing, omnidirectional alarm), a corresponding type of effect object 1 is selected. Effect object 1 serves as the core functional carrier 3 and is designed in various types according to the scenario, such as a blend of metal wire and polymer fiber fabric, a planar grating, or a spherical shell with an electroplated metal film on a PVC substrate. These materials possess high reflectivity or specific light field modulation characteristics. Effect object 1 is fixed in a designated spatial region by thin lines 2, ensuring that its unfolded posture is consistent with the preset posture, thus completing the scenario-adaptive deployment. Next, using a darkened clamping component and a thin cotton thread coated with slurry, the reflectivity around effect object 1 is reduced to avoid background noise interfering with subsequent imaging. The darkening treatment specifically involves anodizing darkening. When the laser link is incident on effect object 1, effect object 1, based on its own characteristics (such as the near-infrared high reflectivity of the blended fabric, the dispersion of the grating, and the specular reflection of the spherical shell), modulates the amplitude, phase, or polarization of the incident light at a subwavelength scale to form a specific light field mode. The modulated optical field signal is captured and imaged by the effector tracking module, providing original signal support for subsequent derivation of parameters such as laser incident direction and wavelength.

[0098] The receiving section of this invention includes three types of detectors: an imaging device for locating effector 1 and link tracking, called the effector tracking module; a laser source tracking module that scans and locks the laser source position at a designated location after link positioning; and a photoelectric detection module consisting of an infrared lens, a photodiode, and a demodulation device (oscilloscope). These are integrated into a single transport unit (i.e., an automatic tracking vehicle). Because they are all general-purpose components, unlike dedicated laser warning systems, these modules can also be used for other detection purposes, such as as laser communication terminals. This invention incorporates a gyroscope-inertial navigation module capable of measuring the current pose of the automatic tracking vehicle. The photodiode used in the photoelectric detection module is connected to the oscilloscope via a BNC cable to display the detection signal in real time and simulate the information interception process. The computer collects all data from each module for further information interception tasks or to issue alarm information. The main body of the automatic tracking vehicle is a four-wheel differential chassis, which can be replaced with other vehicles in actual scenarios.

[0099] The effect object tracking module consists of a rangefinder, camera, motorized focusing lens, support, and motorized turntable. Its function is to locate effect object 1, i.e., to obtain the three-dimensional spatial coordinates of effect object 1. Specifically, the motorized turntable employs an Archimedean spiral scanning method (see...). Figure 2The effect object signal (hereinafter referred to as "spiral scan") is scanned by the light field to control the effect object signal until the effect object signal is aligned with the center of the camera's field of view. Then, the motorized focusing lens is used to make the effect object 1 clearly imaged at the center of the camera's field of view. In terms of ranging and positioning, when the rangefinder error is relatively small, the rangefinder data is collected first; otherwise, the object distance calculated by the current image distance and focal length of the lens is used as the ranging data. First, the coordinates of the alarm unit (the geometric center of the automatic tracking vehicle) are set as the origin O, and the spatial coordinates of the effect object 1 are set as C. The line connecting them, OC, is taken as the Z-axis. The horizontal and vertical directions of the effect object tracking module's field of view are the X and Y axes, respectively. In this way, a three-dimensional spatial reference coordinate system can be established.

[0100] The laser source tracking module has the same structure as the effect object tracking module. Its function is to locate the laser source, i.e., to obtain the three-dimensional spatial coordinates of the laser source. The camera of the laser source tracking module can be selected with a wavelength adapted to the imaging of the laser source, and it is recommended to use the same wavelength as the effect object tracking module. The mirror group, mirror frame, and other components at the laser source's output port easily generate strong scattering signals, which facilitates the laser source location. The incident direction of the laser source can be determined by the effect object signal. The laser source tracking module will scan along the laser incident direction until the laser source is located and the distance is measured through image recognition, thus completing the purpose of locating and alarming the laser threat source. If it is necessary to continue to intercept the modulated information in the laser beam, it can actively approach effect object 1 and use the photoelectric detection module to detect and decipher the modulated light signal (i.e., effect object signal) of the laser link itself or effect object 1.

[0101] The photoelectric detection module uses an adjustable ring-shaped mounting bracket to fix the lens and is coupled to a photodiode. The photodiode is typically an indium gallium arsenide avalanche photodiode, and in this invention, it has a spectral response range of 1000nm-1700nm, a gain of 3.2×10⁶ V / W, a bandwidth of 10MHz, and a rise time of 40ns. Its responsivity is 0.9A / W@1550nm, saturation power is 0.98µW, noise equivalent power (NEP) is 0.42pW / √Hz, and maximum output amplitude is 3.2V. The photoelectric conversion signal is connected to an oscilloscope via a BNC cable to display the waveform of the photoelectric conversion signal. The lens and the long-pass filter mounted on the outside of the diode used to couple the optical signal need to be designed for the wavelength of the laser link. For example, in this invention, the measured wavelength of the laser link is 1550nm. Selecting a bandpass filter near 1550nm can maximize the elimination of background signal interference. The corresponding lens needs to have high transmittance at the 1550nm wavelength to ensure that the target laser signal can be effectively transmitted to the photodetector module and avoid signal attenuation affecting subsequent analysis. The demodulation device used in this invention is an Agilent MSO7104B 4 GSa / s digital oscilloscope. With an input resistance of 50Ω (this is the load resistance setting used in actual acquisition to maximize the high sensitivity of the photodiode) and a signal greater than 10 mV, the relative error of the calibration does not exceed 1%, the rise time does not exceed 500ps, and the highest frequency resolution is 1GHz. The photoelectric detection module is mounted on a four-degree-of-freedom robotic arm, capable of covering all azimuth and polar angles. It can perform detection either by modulating the signal of effector 1 based on the optical field, or by approaching and intruding into the optical path. It's important to note that because detection requires high power, even with a high-power laser link, detection must be performed as close to effector 1 as possible. Furthermore, compared to the effector tracking module, the photoelectric detection module is much more sensitive to azimuth and angular accuracy; therefore, it is not recommended to integrate the effector tracking module and the photoelectric detection module together via beam splitting.

[0102] Meanwhile, the automatic tracking vehicle is equipped with a high-precision gyroscope (i.e., gyroscope inertial navigation module) to monitor the vehicle's rotation angle in real time, ensuring that the coordinate system changes caused by attitude adjustments are taken into account.

[0103] Since the application scenarios involved in this invention are usually on a large scale, such as spatial application scenarios of more than 50 km, this invention provides a corresponding equivalent scaled-down experimental design method, which facilitates researchers to use miniature scenario experiments to demonstrate the feasibility of the scheme. The equivalent scaled-down experimental method is as follows:

[0104] The target scenario for this experiment can be an altitude of more than 10 km or an outer space of more than 100 km. Therefore, it is necessary to use the small target radar equation as the core equation to perform an equivalent scaling-up experiment on the ground.

[0105] First, the radar equation for small targets is:

[0106] ;

[0107] in, P 0 represents the emission power of the laser link beam (the laser link beam is the laser beam emitted by the laser source in a real application scenario, which may be encoded); P r The transmit power of the effector signal received by the effector module; i Tx The beam divergence angle of the laser link beam; D The distance between the transmitting module and effector 1; r h The reflectance of effector 1 can be measured using an integrating sphere; Let be the effective scattering area of ​​the effector in the direction of laser irradiation, where The angle between the laser beam direction and the normal to the plane of the effector is denoted as . The duty cycle of effector 1; S The projected area is the area of ​​effector 1, which is affected by the direction of irradiation and the extent of its spread. For example, if effector 1 is a sphere, then the projected area is the maximum cross-section of the sphere.

[0108] A c = πD c 2 / 4 represents the optical flux area received by the effector tracking module. D c The effective aperture diameter of the receiver of the effect object tracking module;

[0109] oh r The diffraction solid angle of effector 1 is inversely proportional to the light field intensity of effector 1 in the detector direction. It is also a key parameter for light field modulation of effector 1 and can be measured using a wavefront detector.

[0110] or 1 and or 2 represents the transmittance of the laser emitter's optical system and the propagation process, respectively.

[0111] In step S1, the calculation parameters for the real application scenario are preset, namely, the transmit power of the effector signal received by the effector module to be solved in the small target radar equation.P r All others are calculation parameters that need to be preset according to actual application requirements.

[0112] The equivalent scaling equation derived from the radar equation is as follows:

[0113] ;

[0114] in, P r To ensure that the target power, i.e. the laser power of the effector signal received by the effector tracking module, is as consistent as possible with the detector in real outer space, so as to ensure that similar or more sophisticated imaging receiving systems can clearly image the target, thereby demonstrating the feasibility of the imaging receiving system in actual combat scenarios, the same variable as the transmission power of the effector signal received by the effector module above is used. P t The laser power of the encoded laser signal emitted by the transmitting module. S B To encode the cross-sectional area of ​​the laser beam on the effector, r h The reflectance of the effector R d The distance between the effect tracking module and the effect module in an equivalent scaled-down scenario. or This is the transmittance correction factor, set to 1.

[0115] It should be noted that in the equivalent scale-down scenario, the distance between the effector tracking module and the effector module can be set to 7m to 9m. Then, based on the equivalent scale-down equation, the laser power of the coded laser signal emitted by the transmitting module can be calculated. In addition, the equivalent scale-down equation and the small radar target equation have some overlapping parameters, except for the distance between the effector tracking module and the effector module and the laser power of the coded laser signal emitted by the transmitting module. Regarding these overlapping parameters, in the actual calculation process, the preset parameters used in the calculation of the small radar target equation are consistent with the parameter values ​​actually measured by setting up the equivalent scale-down equation, so as to ensure the normal progress of subsequent tests and the accuracy of the calculation results.

[0116] In step S3, the preset range refers to the laser power of the effect object tracking module receiving the effect object signal reflected by the effect object module in the equivalent scale scenario being 50%-100% of the laser power of the effect object tracking module receiving the effect object signal reflected by the effect object module in the real application scenario. The laser power of the emitted coded laser signal of the transmitting module is adjusted according to a specific step size in the equivalent scale scenario until the effect object image acquired by the effect object tracking module is a clear image in the equivalent scale scenario.

[0117] Among the above parameters, the beam cross-sectional areaS B (Limited by laser and collimating lens settings), the light flux area received by the effect tracking module A c (Limited by detector aperture) is a characteristic of the detection device and communication link itself, and can be set as a static variable; effect 1 reflectivity r h diffraction solid angle of effector 1 oh r Due to the light field modulation characteristics of effector 1, it is a non-tunable term; while the laser power P t Distance between the effector tracking module and the effector module R d It can easily achieve real-time stepless adjustment.

[0118] The effective scattering area in the detection direction is written in the following form:

[0119] ;

[0120] Calculations show that the effective scattering area in the detection direction is 3.660 m². 2 The actual scene detector received the emission power of effector 1. P r It is 0.1527pW.

[0121] S B The cross-sectional area of ​​the beam is 4.2822 × 10⁻⁶ mm, with a diameter of 233.5 mm. 4 mm 2 ;

[0122] r h The reflectance of effector 1 is 0.8;

[0123] A r Let be the effective scattering area of ​​effector 1, and be the area of ​​effector (100 mm). 2 The product of the beam projection ratio (cos(0°)=1) and the duty cycle, i.e., 100 mm 2 ;

[0124] A c The area of ​​light received by the detector in the effector tracking module is 1.0752 × 10⁻⁶ mm. The detector aperture is 37 mm. 3 mm 2 ;

[0125] oh dis the scattering spherical angle, and is the reciprocal of the scattering probability density (0.366), i.e., 2.7322;

[0126] or This is the transmittance correction factor, which is 1 in the simulation, assuming that the optical settings used are exactly the same as in reality.

[0127] R d With laser power P t Duality, when R d At a depth of 5.761m, the laser power can be calculated using the equivalent scaling equation. P t It is 6.89 μW As long as the laser irradiation power is 6.89 μW If the effect object 1 can be clearly imaged and successfully identified, then the positioning of the effect object 1 can be considered successful. In this invention, the laser power can be set to 5.6. μW (81% of laser power).

[0128] In the equivalent scaled-down ground test, the light field modulation effector 1 was first moved along the beam propagation direction until the beam spot diameter on the sample cross-section was approximately 200 mm. The automatic tracking vehicle was then moved to obtain a distance measurement result of 5.761 m and a monitoring angle of 20.5°, and the detector integration time was set to 48.81 ms.

[0129] like Figure 3 As shown, Figure 3 Image (a) in the image is an image of the effect under strong light illumination. Figure 3 (b) in the figure is an image of the effect object under low light illumination. Under low light illumination, the average gray value is 6.1 (background removed), and the highest gray value can reach 30.0, which is on the same order of magnitude as the simulation result (gray value 77), verifying the feasibility of extending the equivalent scale model to the actual scene.

[0130] The light field modulation effect material 1 can be a fabric made of metal wire and polymer fiber blend, which has the characteristics of high absorption rate in the visible band and high reflectivity in the near-infrared band. Therefore, it is suitable for tracing near-infrared laser links. At the same time, the material also has the characteristics of concealment in space (without atmospheric scattering light background), and can be used as a typical material of the light field modulation effect material 1.

[0131] The light field modulation effector 1 can also be a mirror-reflective spherical shell. A thin spherical shell matrix is ​​blown using PVC material, with an inner layer of aluminum or silver film electroplated. Helium is then filled into the inner cavity of the spherical shell and sealed, allowing it to levitate in a designated airspace, thereby performing tasks such as ground-to-space and sea-to-space laser communication and laser countermeasure scenarios.

[0132] The incident angle is determined by recognizing the peak value of the bright spot caused by the reflected laser relative to the imaging position of the specular reflective spherical shell in the effect object tracking module. The specific steps are as follows:

[0133] A clear image of the specularly reflecting spherical shell is formed and its distance is measured. Let the diameter of the image of the specularly reflecting spherical shell be . D im 1 pixel;

[0134] Calculate the pixel offset (Δ) of the peak grayscale point of the reflection relative to the center of the image circle of the specular reflection spherical shell. x ,Δ y );

[0135] Construct a local coordinate system with the geometric center of the mirror-reflecting spherical shell as the origin, and calculate the normalized offset. The coordinates of the reflection point on the specularly reflecting spherical shell in the local coordinate system are determined based on the normalized offset. S n (s x ,s y ,s z )satisfy:

[0136] ;

[0137] Mapping the coordinates of the reflection point on the specularly reflecting spherical shell in the local coordinate system back to the real application scenario, we obtain the coordinates of the reflection point on the specularly reflecting spherical shell in the three-dimensional reference coordinate system:

[0138] ;

[0139] Now, let the coordinates of the sphere's center be the origin. O (0,0,0), then the normal vector of the reflecting surface = S - C The reflection vector is denoted as... = According to the law of reflection in vector form, the unit vector of the laser incident direction can be obtained:

[0140] .

[0141] like Figure 5 As shown, Figure 5 (a) in the diagram is a schematic diagram of the modulation optical path, in which, Let be the unit vector of the laser incident direction. The normal vector of the reflecting surface. For reflection vector, Figure 5 (b) in the diagram is a schematic diagram for solving the coordinates of the reflection point, where s x and s yThese are the x and y coordinates of the reflection point on the specularly reflecting spherical shell in the image of the specularly reflecting spherical shell, respectively, in the local coordinate system. Figure 5 In (a), the optical path can provide early warning. The laser beam direction includes a solid angle of a hemisphere, and omnidirectional laser warning can be achieved by deploying multiple modulating effectors 1 within a certain range.

[0142] In some embodiments, in order to ensure that the laser energy can be applied effectively and uniformly to the target area, the spacing between the target objects (effect objects 1) should be less than or equal to the diameter of the laser beam spot formed in that area, so as to avoid incomplete energy coverage or uneven effect.

[0143] In some embodiments, if the effector 1 is a mirror-reflecting spherical shell, the three-dimensional spatial coordinates of the laser source are obtained by single-frame single-target positioning, single-frame multi-target positioning, or multi-frame multi-target positioning; if the effector 1 is a fabric made of metal wire and polymer fiber blend, the three-dimensional spatial coordinates of the laser source are obtained by single-frame multi-target positioning or multi-frame multi-target positioning.

[0144] It should be noted that the specific method for obtaining the three-dimensional spatial coordinates of the laser source using the single-frame single-target positioning method is as follows: the laser source tracking module rotates and scans around the Y-axis in the opposite direction of the unit vector of the laser incident direction until the laser source appears in the field of view of the laser source tracking module. The three-dimensional spatial coordinates of the laser source in the three-dimensional spatial reference coordinate system are obtained through the rotation angle and distance measurement results.

[0145] Furthermore, assuming the laser source tracking module rotates and scans around the Y-axis until it captures the laser source, the rotation angle θ of the laser source tracking module around the Y-axis is recorded, and the straight-line distance L from the laser source tracking module to the laser source is obtained through ranging. The coordinates of the laser source in the three-dimensional reference coordinate system are then calculated using the following formula:

[0146] ;

[0147] In some embodiments, obtaining the three-dimensional spatial coordinates of the laser source using single-frame multi-target localization or multi-frame multi-target localization in step S5 specifically includes the following steps:

[0148] S51: Acquire effector images, and take effector 1 with effector signal as effective effector 1. If the effector tracking module only acquires a single frame effector image containing no less than two effective effectors 1, then execute step S52. If the effector tracking module acquires multiple frames effector images containing no less than two effective effectors 1, then execute step S53.

[0149] Step S52 includes: taking the three-dimensional spatial coordinates of any two effective effectors 1 in the three-dimensional spatial reference coordinate system, and calculating the laser direction vector using the following formula:

[0150] ;

[0151] in, and These are the three-dimensional spatial coordinates of the two effective effectors 1. The laser direction vector;

[0152] Make the laser direction vector and the normal vector of the effect object 1 plane have the same direction to obtain the final laser direction vector. Rotate the laser source tracking module with the z-axis of the three-dimensional space reference coordinate system as the center so that the projection of the final laser direction vector on the XOY plane of the three-dimensional space reference coordinate system coincides with the X-axis. The laser source tracking module rotates and scans around the Y-axis in the opposite direction of the final laser direction vector until the laser source appears in the field of view of the laser source tracking module. The three-dimensional space coordinates of the laser source in the three-dimensional space reference coordinate system are obtained by the rotation angle and the distance measurement results.

[0153] Step S53 includes: taking the three-dimensional spatial coordinates of any two effective effect objects 1 in any two frames of effect object images, and calculating the tracking vector of the corresponding effective effect object 1 using the following formula:

[0154] ;

[0155] ;

[0156] in, Let be the tracing vector formed by the two effective effect objects 1 in the effect object image of the m-th frame. Let be the tracing vector formed by the two effective effect objects 1 in the nth frame effect image. and Let be the three-dimensional spatial coordinates of the two effective effectors 1 in the m-th frame effector image. and Let be the three-dimensional spatial coordinates of the two effective effectants 1 in the nth frame of the effectant image;

[0157] The tracking vector is calculated using the following formula. and tracking vector All perpendicular normal vectors :

[0158] ;

[0159] in, For the tracking vector and tracking vector All perpendicular normal vectors;

[0160] make ∈ Solving for the tracing vector The corresponding spatial line and tracing vector The common perpendicular of the corresponding spatial lines, and the common perpendicular and the tracking vector. The intersection of the corresponding spatial lines serves as the position approximation point for the effect image in the m-th frame. The common perpendicular and the tracking vector The intersection of the corresponding spatial lines serves as the position approximation point for the effect image in the nth frame. The approximation point is calculated using the following formula. and location proximity point Three-dimensional spatial coordinates:

[0161] ;

[0162] Approach the location and location proximity point The three-dimensional spatial coordinates of the midpoint of the line connecting the two points are used as the three-dimensional spatial coordinates of the laser source.

[0163] It should be noted that in step S53, the delay between any two selected effect object images does not exceed 50 ms.

[0164] Furthermore, when the spatial density of effector 1 (which is a fabric blend of metal wire and polymer fiber) is high, the three-dimensional spatial coordinates of more than two effective effectors 1 (scattering signals) in the three-dimensional reference coordinate system can be obtained in the same frame of the effector image. In this case, the three-dimensional spatial coordinates of two effectors 1 with different responses in the three-dimensional reference coordinate system can be used for ray tracing, which is beneficial for locking the laser link source. At this time, the laser direction vector can be represented as:

[0165] ;

[0166] The positive and negative signs represent the two opposite directions of the laser beam. The actual laser link direction should be opposite to the normal vector direction of the plane of the effector 1. We can eliminate any solution that does not meet the requirements.

[0167] If the laser beam is tracked in two different frames of the effect object as it moves, there is no need to scan in the opposite direction of the laser incident; the laser source can be located directly using the focal points of the two laser beams in opposite directions.

[0168] Let the tracking vector be represented in the effect image of the m-th frame and the effect image of the n-th frame, respectively:

[0169] ;

[0170] and and All perpendicular normal vectors It can be represented as:

[0171] ;

[0172] To ensure accurate positioning, the normal vector needs to be... model Control within a range Let R be the distance between the laser source and the laser source tracking module. T Then the maximum value For R T 2 minimum value 0.1R T .when At that time, it can be considered and Parallelism failed, positioning failed; continue scanning in the opposite direction of laser incidence. If positioning is successful, let the position of the laser source in the m-th frame of the effect image be... The position of the effect in the nth frame image is When the times of the m-th frame effect image and the n-th frame effect image are close, the directed perpendicular line segment formed by connecting the feet of the perpendiculars of the common perpendiculars of the planes containing the spatial lines corresponding to the two tracking vectors mentioned above is the best approximation of the displacement of the OCT transmitter signal source. Let the position approximation in the m-th frame effect image be denoted as . The position of the effect object in the nth frame image is approximated as By simultaneously solving the equations of two spatially symmetric lines and the approximation point... By connecting the common perpendicular line and finding its symmetric equation, we can find the approximate point. , The three-dimensional spatial coordinates are given, and the following system of simultaneous equations is used to solve for them:

[0173] ;

[0174] Each symmetric equation is equivalent to two linear equations, and a total of six independent linear equations are solved simultaneously, which allows us to find the approximation point. , The three-dimensional spatial coordinates. When the two frames of the effect object images are close enough, and the displacement of the OCT transmitter itself is small, the line segment can be... The midpoint is used as the three-dimensional spatial coordinate of the laser source. If the scattering of the laser source's output port can be detected, it means that the laser source has been locked and an alarm action can be executed.

[0175] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0176] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A non-coaxial laser alarm method, characterized in that: Specifically, the steps include the following: S1: Build a non-coaxial laser alarm system including a transmitting module, an effector tracking module, an effector module and a laser source tracking module, preset the calculation parameters of the real application scenario, and use the small target radar equation to calculate the laser power of the effector tracking module receiving the effector signal reflected by the effector module in the real application scenario. S2: Construct an equivalent scaling equation. Preset the distance between the effect tracking module and the effect module in the equivalent scaling scenario. Substitute the calculation result of step S1 into the equivalent scaling equation to calculate the laser power of the coded laser signal emitted by the transmitting module. S3: Adjust the laser power of the coded laser signal emitted by the transmitting module in the equivalent scale scenario so that the laser power of the effect object tracking module receiving the effect object signal reflected by the effect object module in the equivalent scale scenario is within a preset range. S4: In the equivalent scale scenario, the effect object tracking module is used to acquire the effect object image of the effect object module. If the effect object image acquired by the effect object tracking module is a clear image, then step S5 is executed; otherwise, step S3 is executed until the effect object image acquired by the effect object tracking module is a clear image. S5: In real-world application scenarios, deploy no fewer than two effectors, use a non-coaxial laser alarm system to capture effector information, and locate the three-dimensional spatial coordinates of the laser source based on the type of effector.

2. The non-coaxial laser alarm method according to claim 1, characterized in that: The non-coaxial laser warning system also includes a gyroscope inertial navigation module and an optoelectronic detection module. Furthermore, the effect object tracking module, laser source tracking module, gyroscope inertial navigation module, and optoelectronic detection module are all mounted on the automatic tracking vehicle. The transmitting module is used to emit coded laser signals; The effector module is used to hold the effector, which receives and modulates the encoded laser signal to obtain the effector signal; The effect object tracking module is used to capture effect object signals, so that the effect object is clearly imaged at the center of the field of view of the camera that is equipped with the effect object tracking module, and obtains the three-dimensional spatial coordinates of the effect object by constructing a three-dimensional spatial reference coordinate system. The laser source tracking module is used to scan the light field along the laser incident direction. It uses a camera to capture the strong scattering signal of the laser source exit lens group and combines it with a three-dimensional spatial reference coordinate system to realize the three-dimensional spatial coordinate measurement of the laser source. The gyroscope inertial navigation module is used to monitor the rotation angle and current pose changes of the automatic tracking vehicle in real time, and to perform real-time compensation on the three-dimensional spatial reference coordinate system based on the monitoring results. The photoelectric detection module is used to receive coded laser signals, convert them into electrical signals, and perform filtering, demodulation, and waveform analysis on the electrical signals to intercept and decipher the modulation and coding information in the coded laser signals.

3. The non-coaxial laser alarm method according to claim 2, characterized in that: Let the geometric center of the effect object be C. The three-dimensional spatial reference coordinate system is constructed with the geometric center of the automatic tracking vehicle as the origin O, the line connecting OC as the Z-axis, the horizontal direction of the field of view of the effect object tracking module's camera as the X-axis, and the vertical direction of the field of view of the effect object tracking module's camera as the Y-axis.

4. The non-coaxial laser alarm method according to claim 3, characterized in that: The effect module includes a fixture, a carrier, and an effect. The fixture holds the carrier, the carrier carries the effect, and the back of the effect is attached to the carrier by fine cotton threads in three directions. The fixture and the carrier are anodized and darkened, and the fine cotton threads are coated with a highly conductive paste.

5. The non-coaxial laser alarm method according to claim 4, characterized in that: The effector is a fabric made of a blend of metal wires and polymer fibers or a mirror-reflective spherical shell.

6. The non-coaxial laser alarm method according to claim 1, characterized in that: In step S1, the small target radar equation is: ； in, P 0 represents the emission power of the laser link beam. P r The laser power of the effector signal received by the effector tracking module. θ Tx The beam divergence angle, D The distance between the transmitting module and the effector. η 1 and η 2 represents the transmittance of the laser emitter's optical system and the transmission process, respectively. D r This represents the distance between the effector tracking module and the corresponding effector module in a real-world application scenario. ρ h The reflectance of the effector A r The effective scattering area of ​​the effector A c The area of ​​light received by the effector tracking module. ω r The diffraction solid angle of the effector is denoted as .

7. The non-coaxial laser alarm method according to claim 6, characterized in that: In step S2, the expression for the equivalent scaling equation is: ； in, P t The laser power of the encoded laser signal emitted by the transmitting module. S B To encode the cross-sectional area of ​​the laser beam on the effector, ρ h The reflectance of the effector R d The distance between the effect tracking module and the effect module in an equivalent scaled-down scenario. η This is the transmittance correction factor. A r The effective scattering area of ​​the effector A c The area of ​​light received by the effector tracking module. ω r The diffraction solid angle of the effector is denoted as .

8. The non-coaxial laser alarm method according to claim 5, characterized in that: If the effector is a specular reflective spherical shell, the specular reflective spherical shell is fixed to the effector module. The effector tracking module is used to create a clear image of the specular reflective spherical shell, obtaining an image of the specular reflective spherical shell. The distance between the specular reflective spherical shell and the effector tracking module is obtained using the rangefinder of the effector tracking module. Let the image diameter of the specular reflective spherical shell in the image be... D im 1 pixel; Calculate the pixel offset (Δ) of the peak grayscale point of the specular reflective spherical shell relative to the image center of the specular reflective spherical shell. x ,Δ y ); A local coordinate system is constructed with the geometric center of the specularly reflecting spherical shell as the origin. The normalized offset is calculated, and the coordinates of the reflection point on the specularly reflecting spherical shell in the image are determined in the local coordinate system based on the normalized offset. s x , s y , s z The process includes the following formula: ； ； Map the coordinates of the reflection point on the mirrored spherical shell in the image of the mirrored spherical shell back to the real application scenario to obtain the coordinates of the reflection point on the mirrored spherical shell in the three-dimensional reference coordinate system. Obtain the normal vector and reflection vector of the reflecting surface of the specular reflective spherical shell, and set the normal vector of the reflecting surface of the specular reflective spherical shell as... Let the reflection vector of the specular reflective spherical shell be set as Calculate the unit vector of the laser incident direction. : = S - C； ； ； in, S Let C be the coordinates of the reflection point on the mirror-reflecting spherical shell in the three-dimensional reference coordinate system, and let C be the coordinates of the geometric center of the effect object in the three-dimensional reference coordinate system.

9. The non-coaxial laser alarm method according to claim 8, characterized in that: In step S5, if the effector is a mirror-reflecting spherical shell, the three-dimensional spatial coordinates of the laser source are obtained by using single-frame single-target localization, single-frame multi-target localization, or multi-frame multi-target localization; if the effector is a fabric made of metal wire and polymer fiber blend, the three-dimensional spatial coordinates of the laser source are obtained by using single-frame multi-target localization or multi-frame multi-target localization. The specific method for obtaining the three-dimensional spatial coordinates of the laser source using single-frame single-target localization is as follows: the laser source tracking module rotates and scans around the Y-axis in the opposite direction of the unit vector of the laser incident direction until the laser source appears in the field of view of the laser source tracking module. The three-dimensional spatial coordinates of the laser source in the three-dimensional spatial reference coordinate system are obtained by the rotation angle and the ranging results.

10. The non-coaxial laser alarm method according to claim 9, characterized in that: In step S5, obtaining the three-dimensional spatial coordinates of the laser source using single-frame multi-target localization or multi-frame multi-target localization specifically includes the following steps: S51: Acquire effector images, and take effectors with effector signals as valid effectors. If the effector tracking module only acquires a single frame effector image containing no less than two valid effectors, then execute step S52. If the effector tracking module acquires multiple frames effector images containing no less than two valid effectors, then execute step S53. Step S52 includes: taking the three-dimensional spatial coordinates of any two effective effectors in the three-dimensional reference coordinate system, and calculating the laser direction vector using the following formula: ； in, and These are the three-dimensional spatial coordinates of the two effective effectors. The laser direction vector; The laser direction vector is aligned with the normal vector of the effect object plane to obtain the final laser direction vector. The laser source tracking module is rotated around the z-axis of the three-dimensional spatial reference coordinate system so that the projection of the final laser direction vector onto the XOY plane of the three-dimensional spatial reference coordinate system coincides with the X-axis. The laser source tracking module then rotates and scans around the Y-axis in the opposite direction of the final laser direction vector until the laser source appears in the field of view of the laser source tracking module. The three-dimensional spatial coordinates of the laser source in the three-dimensional spatial reference coordinate system are obtained through the rotation angle and ranging results. Step S53 includes: taking the three-dimensional spatial coordinates of any two effective effect objects in any two frames of effect object images, and calculating the tracking vector of the corresponding effect object image using the following formula: ； ； in, Let be the tracing vector formed by two effective effectors in the effector image of the m-th frame. Let be the tracing vector formed by two effective effectors in the nth frame effector image. and Let be the three-dimensional spatial coordinates of the two effective effectors in the m-th frame effector image. and Let be the three-dimensional spatial coordinates of the two effective effectors in the nth frame of the effector image; The tracking vector is calculated using the following formula. and tracking vector All perpendicular normal vectors : ； in, For the tracking vector and tracking vector All perpendicular normal vectors; make ∈ Solving for the tracing vector The corresponding spatial line and tracing vector The common perpendicular of the corresponding spatial lines, and the common perpendicular and the tracking vector. The intersection of the corresponding spatial lines serves as the position approximation point for the effect image in the m-th frame. The common perpendicular and the tracking vector The intersection of the corresponding spatial lines serves as the position approximation point for the effect image in the nth frame. The approximation point is calculated using the following formula. and location proximity point Three-dimensional spatial coordinates: ； Approach the location and location proximity point The three-dimensional spatial coordinates of the midpoint of the line connecting the two points are used as the three-dimensional spatial coordinates of the laser source.

Images