Optical scanning target positioning method and system

Abstract

The invention provides an optical scanning target positioning method and system, and the method comprises the steps: starting a laser, generating a laser beam, and dividing the laser beam into a plurality of sub-beams through an optical fiber beam splitter; modulating the sub-beams through an optical modulator, and outputting the sub-beams to corresponding collimators; adjusting the angle of the collimator based on the distance and power density requirements of a target object, and controlling the collimator to rotate to form a scanning area; the collimator rotates through a rotating structure; and receiving a light return signal of the sub-beam reflected by a reflecting prism on the target object, and determining position information of the target object based on the light return signal. According to the invention, the application requirement of high precision can be met while high efficiency is achieved, and the problem that the scanning efficiency and the scanning precision are difficult to consider at the same time in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the field of optical scanning technology, and in particular to an optical scanning target positioning method and system. Background Art

[0002] Optical scanning and target positioning are key technologies in industrial inspection, monitoring systems, robotic navigation, and laser communications. Industrial inspection applications, such as surface defect identification and dimensional measurement, require rapid scanning of large areas while accurately locating the defect. In monitoring systems, these applications involve large-scale target monitoring, such as rapid baggage scanning at airport security. Existing methods suffer from low coverage and target recognition accuracy. In robotic navigation, environmental perception and obstacle location, such as autonomous driving, require real-time road scanning. Existing systems struggle to balance accuracy and speed in dynamic and complex environments. In laser communications, communication is typically point-to-point, with a very small beam divergence angle, requiring precise alignment. Scanning and capture are prerequisites for establishing space laser communication links. However, due to various errors, such as attitude errors, servo control errors, actuator errors, and axis errors, precise target positioning cannot be achieved. This results in significant deviations in pitch and azimuth between the laser transmitter and receiver. To achieve a certain target coverage probability, scanning must be performed within an uncertain area. Current scanning methods all suffer from various issues, including high scan miss rates, low scanning efficiency, low scanning accuracy, and high system complexity.

[0003] The commonly used scanning methods are as follows: Single-beam scanning, including raster scanning, spiral scanning, and raster spiral scanning, has a simple scanning structure and is easy to implement. This method is suitable for small field of view scenes. However, when faced with large-area scanning tasks, its efficiency is obviously insufficient, and it often takes several minutes or even longer to scan, and it is also accompanied by the problem of high missed scanning rate. In order to optimize the scanning path, modes such as rose scanning, Lissajous scanning, and hexagonal scanning have emerged. These modes theoretically improve efficiency by reducing repeated paths or optimizing the inflection point distribution. However, in practical applications, the implementation of these modes faces many challenges: First, the speed changes drastically at the inflection point, which makes it difficult to accurately control the mechanical components, and easily produces missed scanning areas or uneven scanning; second, the control algorithm is complex and has high requirements on hardware performance, which increases system cost and maintenance difficulty.

[0004] Linear laser scanning achieves high-efficiency scanning of large uncertain areas by increasing the coverage area of the laser unit and moving or rotating it quickly. However, when scanning the target, the feedback error is too large and the accuracy is low. The requirements for subsequent processing units are too high, making it difficult to apply to scenarios with high precision requirements.

[0005] In summary, the core problem of existing technologies lies in the trade-off between scanning efficiency, positioning accuracy, and field of view coverage. For example, to improve efficiency, the system may speed up coverage by increasing the beam divergence angle or the detector field of view, but this will lead to a decrease in accuracy; conversely, to improve accuracy, the system slows down the scanning speed or beam divergence angle and reduces the field of view, which undoubtedly sacrifices efficiency. In addition, high control difficulty and algorithm complexity are also major difficulties in the actual implementation process. For example, the speed difference between the center and edge areas of spiral scanning is significant, and mechanical components are prone to jitter or deviation during rapid switching, resulting in missed scans and repeated scans. For example, in Lissajous scanning, the complexity of the curve places extremely high demands on the computing power and response speed of the control system, and ordinary hardware may not be able to cope with it.

[0006] There is currently no effective solution to the problem of difficulty in balancing scanning efficiency and scanning accuracy in existing related technologies. Summary of the Invention

[0007] The present invention provides an optical scanning target positioning method and system, which are used to solve the defect in the existing related technologies that it is difficult to strike a balance between scanning efficiency and scanning accuracy.

[0008] In a first aspect, the present invention provides an optical scanning target positioning method, comprising: Turning on the laser to generate a laser beam, and dividing the laser beam into a plurality of sub-beams through a fiber optic beam splitter; The sub-beams are modulated by an optical modulator and output to the corresponding collimator. The purpose is to give each sub-beam unique modulation information, which is used to distinguish the different directions pointed by the beams corresponding to different modulation information when the detector detects the return light, so as to achieve high-efficiency scanning while having the same accurate direction pointing; Based on the distance and power density requirements of the target object, the angle information of the collimator is adjusted, and the collimator is controlled to rotate to form a scanning area; the collimator is rotated by a rotating structure, and a reflective prism is pre-set on the target object; A return light signal generated when the sub-beam is reflected by a reflective prism on the target object is received, and position information of the target object is determined based on the return light signal.

[0009] According to an optical scanning target positioning method provided by the present invention, the sub-beam is modulated by an optical modulator and output to a corresponding collimator, comprising: Each of the sub-beams enters a different optical modulator for modulation, and the modulation parameters include one or more of amplitude, carrier frequency and phase; The modulated sub-beam is output-coupled into an optical fiber and passes through a smooth ring into the corresponding collimator; the smooth ring is used to assist in controlling the rotation of the collimator.

[0010] According to an optical scanning target positioning method provided by the present invention, in the scanning area, the sub-beams are adjacent to each other and arranged linearly, and the sum of the diameters of the sub-beams is equal to the radius of the scanning area.

[0011] According to an optical scanning target positioning method provided by the present invention, receiving a return light signal of the sub-beam reflected by a reflective prism on the target object, and determining the position information of the target object based on the return light signal, including: When the sub-beam scans the target object, the reflective prism on the target object returns the sub-beam along the original optical path; The detector at the transmitting end receives the return light signal of the sub-beam and determines the relative pitch angle and azimuth angle of the target object based on the return light signal.

[0012] According to an optical scanning target positioning method provided by the present invention, a detector at a transmitting end receives a return light signal of the sub-beam, and determines a relative pitch angle and azimuth angle of the target object based on the return light signal, comprising: The transmitter detector demodulates the unique characteristic information in the return light signal; The unique feature information, detector information, rotation structure information and angle information of the collimator are comprehensively used to perform a pointing solution to obtain the relative pitch angle and azimuth angle of the target object.

[0013] In a second aspect, the present invention further provides an optical scanning target positioning system for implementing the optical scanning target positioning method described in the first aspect, comprising: a laser generating unit, for generating a laser beam; a laser beam splitting unit, configured to split the laser beam into a plurality of sub-beams; a laser modulation unit, configured to modulate the sub-beams and distinguish different sub-beams; A beam emitting unit, configured to emit the sub-beam carrying light modulation information at a specific beam divergence angle to form a scanning light spot; the beam emitting unit includes a collimator; A beam angle adjustment unit, used to control the rotation of the collimator to form a scanning area; The light receiving unit is configured to receive a return light signal generated when the sub-beam is reflected by a reflective prism on the target object, and determine position information of the target object based on the return light signal.

[0014] According to an optical scanning target positioning system provided by the present invention, the laser generating unit includes a semiconductor laser, and the wavelength of the laser light generated by the semiconductor laser is 850nm-1550nm; the laser beam splitting unit includes a fiber beam splitter.

[0015] According to an optical scanning target positioning system provided by the present invention, the laser modulation unit includes a light modulator; Used to modulate the sub-beam, including: intensity modulation, frequency modulation, and wavelength modulation.

[0016] According to an optical scanning target positioning system provided by the present invention, the system further includes a smooth ring, which is located between the laser modulation unit and the light beam emitting unit, and is used to assist in controlling the rotation of the collimator.

[0017] According to an optical scanning target positioning system provided by the present invention, the beam angle adjustment unit includes a rotating structure and a collimator angle control member; The rotating structure is used to control the synchronous rotation of all collimators; an angle sensor is provided on the rotating structure to obtain angle information of the collimators; The collimator angle control member is used to independently adjust the pointing angle of each collimator according to the distance of the target object.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The optical scanning target positioning method provided by the present invention can cover a larger area in a single scan, thereby significantly reducing the required scanning time. At the same time, through optimized design, the effective area of the light beam in the scanning cross section is ensured to remain unchanged, which not only improves efficiency but also maintains the scanning coverage and quality. Moreover, the present method adopts a multi-beam scanning method in which the light beam is modulated. By assigning a unique identifier to each light beam, it can accurately identify the source of the reflected sub-beam, thereby effectively distinguishing the position of the target object, overcoming the defect of large error under large spot size, and significantly improving the positioning accuracy during rapid scanning, so that the present method can meet the application requirements of high precision while being highly efficient, and solves the problem of difficulty in balancing scanning efficiency and scanning accuracy in existing related technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1is a flow chart of the optical scanning target positioning method provided by the present invention; Figure 2 Schematic diagram of the rotation mode of the rotating structure in an embodiment of the present invention; Figure 3 is a schematic diagram of forming a scanning area in an embodiment of the present invention; Figure 4 is a schematic diagram of the position coordinates of a target object, a collimator, and a target object reflecting prism in an embodiment of the present invention; Figure 5 is a schematic diagram of the process of scanning and target positioning in an embodiment of the present invention; Figure 6 is a schematic diagram of the coordinates of the rotating structure and the collimator in an embodiment of the present invention; Figure 7 Schematic diagram comparing spiral scanning and scanning by this method; Figure 8 This is a schematic diagram comparing this method with linear laser rapid scanning; Figure 9 Schematic diagram of the optical scanning target positioning system provided by the present invention. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0022] The present invention provides an optical scanning target positioning method. Figure 1 is a flow chart of the optical scanning target positioning method provided by the present invention, such as Figure 1 As shown, the method includes the following steps: Step S101, turning on the laser to generate a laser beam, and dividing the laser beam into several sub-beams through an optical fiber beam splitter; Step S102, amplitude modulating the sub-beams by an optical modulator to generate carrier optical signals of different frequencies, and outputting the signals to corresponding collimators; Step S103, adjusting the angle information of the collimator based on the distance to the target object and the power density requirement, and controlling the rotation of the collimator to form a scanning area; the collimator is rotated by a rotating structure, and a reflective prism is pre-set on the target object; Step S104 : receiving a return light signal of the sub-beam reflected by a reflective prism on the target object, and determining position information of the target object based on the return light signal.

[0023] In this method, a laser beam is first emitted by a laser and then split into multiple sub-beams using a fiber optic beam splitter. An optical modulator then modulates the carrier frequency information of the sub-beams, applying the optical modulation information to the corresponding sub-beams to distinguish the different sub-beams. The modulated sub-beams are then output to the corresponding collimator and emitted through the collimator, forming a light spot. The collimator's angle is then adjusted based on the distance to the target object and the power density requirements, and the collimator's rotation is controlled. The light spot forms a scanning area during the rotation process. When the sub-beams impinge on the target object, the reflective prism on the target object reflects the sub-beams. Based on the reflected glow signal, the target object's position is determined, achieving scanning and positioning of the target object. This process allows a larger area to be covered in a single scan, significantly reducing the required scanning time. Furthermore, through optimized design, the effective area of the beam in the scanning cross-section remains unchanged, improving efficiency while maintaining scanning coverage and quality. Moreover, this method adopts a multi-beam scanning method that modulates the light beam. By giving each light beam a unique identifier, it can accurately identify the source of the reflected sub-beam, thereby effectively distinguishing the position of the target object, overcoming the defect of large error under large spot size, and significantly improving the positioning accuracy during rapid scanning, so that this method can meet high-precision application requirements while being highly efficient, and solves the problem of difficult to strike a balance between scanning efficiency and scanning accuracy in existing related technologies.

[0024] In some embodiments, step S102, amplitude modulating the sub-beams using an optical modulator and outputting them to corresponding collimators, includes: each sub-beam enters a different optical modulator for modulation, where the modulation parameters include one or more of amplitude, carrier frequency, and phase, thereby generating carrier optical signals of different frequencies; the modulated sub-beams are output coupled into an optical fiber and pass through a smooth ring into the corresponding collimator; the smooth ring is used to assist in controlling the rotation of the collimator. The modulation principle of amplitude modulating different sub-beams to generate carrier optical signals of different frequencies is as follows: The initial optical electric field of each sub-beam can be expressed as:

[0025] in, represents the initial optical electric field, represents the optical electric field amplitude, represents the carrier frequency (consistent for all sub-beams), represents the initial phase, and t represents the time.

[0026] Each optical modulator receives an electrical modulation signal , where i represents the i-th sub-beam. Assuming that the modulation signal is a sine wave, then:

[0027] in, represents the optical field amplitude of the modulating signal; represents the modulation frequency (different for each sub-beam); represents the phase of the modulated signal, and t represents time.

[0028] In an optical modulator, the electric field amplitude of the optical signal changes according to the electrical modulation signal. The modulated optical electric field can be approximately expressed as:

[0029] in, represents the modulated optical field, t represents time, and substitute And after expanding this expression we get:

[0030] Based on this spectrum analysis, after sorting out the above expression, we can get:

[0031] As can be seen from the formula, the modulated optical signal contains three frequency components: carrier frequency Upper sideband Lower side band ; Because the modulation frequency of each sub-beam Different, so the sideband frequency of each sub-beam is also different, which can generate carrier optical signals of different frequencies.

[0032] In some embodiments, in the scanning area, the sub-beams are adjacent to each other and arranged linearly, and the sum of the diameters of the sub-beams is equal to the radius of the scanning area.

[0033] In some embodiments, step S104, receiving the return signal of the sub-beam reflected by the reflective prism on the target object, and determining the position information of the target object based on the return signal, includes: when the sub-beam scans the target object, the reflective prism on the target object will return the sub-beam along the original optical path; the transmitting end detector receives the return signal of the sub-beam, and determines the relative pitch angle and azimuth angle of the target object based on the return signal.

[0034] The detector at the transmitting end receives the return signal of the sub-beam and determines the relative pitch angle and azimuth angle of the target object based on the return signal, including: the detector at the transmitting end demodulates the unique characteristic information in the return signal; and performs pointing solution by combining the unique characteristic information, detector information, rotation structure information and angle information of the collimator to obtain the relative pitch angle and azimuth angle of the target object.

[0035] In this method, the collimator is fixed on a rotating structure, the rotating structure plane is the YZ plane, and is perpendicular to the optical axis (X axis). Figure 2 As shown, Figure 2 FIG. 1 is a schematic diagram of the rotation mode of the rotating structure in an embodiment of the present invention. The beam divergence angle of the sub-beam emitted by the collimator is , the distance between the collimator emission end and the target object is L, the energy of a single laser beam is P, the power density of the scanning surface is I, and the diameter of a single beam on the scanning surface is D, as shown Figure 3 As shown in Figure 3 is a schematic diagram of the formation of the scanning area in the embodiment of the present invention. The half-angle width of the uncertain area is , the sub-beams Tn (n is 4 for example) are marked as T1, T2, T3, and T4.

[0036] Sub-beam scanning surface diameter In actual situations, the power density I when the total power P reaches the scanning surface must be considered. The specific formula is as follows: I = P / A

[0037] Where I represents power density, P represents total power, A represents cross-sectional area, and D represents the diameter of the sub-beam scanning surface. This gives the cross-sectional power density I of the light reaching the scanning surface:

[0038] Where I represents power density, P represents total power, A represents cross-sectional area, and L represents the distance between the collimator emission end and the target object. Represents the half-angle of the divergence of a single sub-beam. Therefore, relevant parameters can be set and adjusted based on the power density requirements in actual conditions. The power density I and power P are also key parameter requirements for adjusting the number of beams.

[0039] Since this method uses multi-beam linear arrangement scanning, in a single scan, the area The scan rate can be approximately 0% without considering the error, achieving high coverage and high efficiency scanning. When scanning, the beam rotating part can be combined with the turntable to rotate, and raster scanning, spiral scanning and other methods can be considered to achieve scanning of a larger area of uncertain area.

[0040] This method rotates the structural frame angle , control parts control the collimator angle , beam divergence There will be certain errors in the control of the rotation angle. , the control part controls the collimator angle , beam divergence angle This will eventually affect the calculated pitch and azimuth angles. The following will analyze the above errors in detail: In order to facilitate analysis, first define the coordinate system and parameters. like Figure 4 As shown, Figure 4 Schematic diagram of the position coordinates of the target object, the collimator, and the target object reflecting prism in an embodiment of the present invention. is the rotation center point of the rotating structure, The axis is straight ahead, The axis is to the right, The axis is directly above.

[0041] The initial position of the collimator is as follows Figure 4 As shown, the collimator is along Axis arrangement, the initial position is expressed as:

[0042] in, represents the initial position of the collimator, and n represents the number of collimators, that is, the number of sub-beams.

[0043] Structural frame Axis rotation, the ideal rotation angle is , the actual rotation angle is , the rotation error is .

[0044] The ideal pointing angle planned according to the distance L is , the actual pointing angle is , the control error is .

[0045] The ideal beam divergence angle of the sub-beam is , the actual beam divergence angle is , the beam divergence error is .

[0046] The ideal distance is L, and the actual solution distance is , the distance error is .

[0047] The target object location is , the actual solution position is .

[0048] The pitch angle of the target object is defined as the position of the target object relative to The angle between two planes is given by the following formula:

[0049] in, Indicates the pitch angle of the target object, Represents the target object Axis coordinates, Represents the target object Axis coordinates, Represents the target object Axis coordinates.

[0050] The azimuth of the target object is defined as the The angle between the projection on the plane and the X' axis is as follows:

[0051] in, represents the azimuth of the target object, Represents the target object Axis coordinates, Represents the target object Axis coordinates.

[0052] For the error of the rotating structure, that is, the rotation error: the rotation error causes the actual rotation angle of the rotating structure to deviate from the ideal value, resulting in the position of the collimator to shift, thereby affecting the position of the target object. Ideally, the rotating structure rotates around Axis rotation After that, the collimator position is:

[0053] in, Indicates the position of the collimator after rotation, n indicates the number of collimators, represents the rotation angle of the collimator. Assume that the sub-beam emitted by the collimator is along When the axis direction is not controlled by a control component, the beam direction should be:

[0054] in, Indicates the direction of the beam when there is no control element. The position of the target object is:

[0055] Where T represents the location of the target object, Indicates the position of the collimator after rotation, L indicates the ideal distance, Indicates the beam direction when there is no control component, n indicates the number of collimators, Indicates the rotation angle of the collimator. Affected by the rotation error of the structure frame, the actual rotation angle of the collimator position becomes , and its collimator points to:

[0056] in, Indicates the actual direction of the collimator after rotation, is the rotation error. The actual position of the target object is:

[0057] in, Represents the actual position of the target object. Based on this, the expression of position deviation is as follows:

[0058]

[0059]

[0060] in, express Axis position deviation, express Actual coordinates in the axis direction, express Axis direction coordinates, express Axis position deviation, express Actual coordinates in the axis direction, express Axis direction coordinates, express Axis position deviation, express Actual coordinates in the axis direction, express Axis direction coordinates, is the rotation error.

[0061] For the control error of the collimator: Collimator control error Changing the pointing direction of the sub-beam directly affects the position of the target object. In an ideal situation, assuming no rotation error, only the initial position of the collimator is considered after rotation. After the position:

[0062] in, Indicates the position of the collimator after rotation, n indicates the number of collimators, represents the rotation angle of the collimator. The ideal pointing angle is , the beam pointing is:

[0063] in, Indicates the direction of the beam when there is no control element. Therefore, the position of the target object is:

[0064] Where T represents the location of the target object, Indicates the position of the collimator after rotation, L indicates the ideal distance, Indicates the beam direction when there is no control component, n indicates the number of collimators, represents the rotation angle of the collimator. The position deviation of the target object is as follows:

[0065]

[0066]

[0067] in, express Axis position deviation, express Actual coordinates in the axis direction, express Axis direction coordinates, express Axis position deviation, express Actual coordinates in the axis direction, express Axis direction coordinates, express Axis position deviation, express Actual coordinates in the axis direction, express Axis direction coordinates, Represents the collimator control error.

[0068] Beam divergence error for sub-beams: Beam divergence error Affects the divergence of the light beam, mainly changing the spot size and the intensity of the return signal, and does not directly affect the center direction of the beam or the position of the target object. The expression of the ideal spot diameter is:

[0069] Where D is the ideal spot diameter, L is the distance to the target object, represents the beam divergence angle of the sub-beam. The expression of the actual spot diameter is as follows:

[0070] in, Indicates the actual spot diameter, Represents beam divergence error. Changes in the spot size can affect the intensity and distribution of the return signal, indirectly impacting the accuracy of the target distance calculation. Beam divergence error does not directly alter the center direction of the sub-beams, so the actual position of the target is unaffected. Since the actual position of the target remains unchanged, the target's elevation and azimuth angles are also unaffected.

[0071] Next, we analyze the impact of rotation error and collimator control error on target orientation. The actual position of the collimator is as follows:

[0072] in, Indicates the actual direction of the collimator after rotation, is the rotation error. The actual beam pointing direction of the sub-beam is as follows:

[0073] in, Indicates the actual beam direction of the sub-beam. The actual position of the target object is as follows:

[0074] in, represents the actual position of the target object. Therefore, the ideal pitch angle is:

[0075] in, represents the ideal pitch angle. The ideal azimuth angle is:

[0076] in, represents the azimuth angle under ideal conditions. The actual pitch angle of the target object is:

[0077] in, Indicates the actual pitch angle of the target object. The actual azimuth angle of the target object is:

[0078] in, Represents the actual azimuth angle of the target object. From this, the angle error can be calculated, where the pitch angle error is as follows:

[0079] in, Indicates the pitch angle error. The azimuth angle error is as follows:

[0080] in, Represents the azimuth error. After calculation, the pitch angle error and azimuth angle error of the target object can be expressed by the following expression:

[0081]

[0082]

[0083] in, represents the pitch angle error, Indicates the azimuth error, v is a custom parameter.

[0084] Figure 5 FIG. 1 is a schematic diagram of the process of scanning and target positioning in an embodiment of the present invention. Figure 5 As shown, in actual application, this method specifically includes the following steps: 1. Turn on the laser to generate a laser beam with the required power, wavelength, frequency and other information, and then pass through the fiber optic beam splitter to split it into n nearly identical sub-beams; 2. N sub-beams enter the optical modulator with different frequency modulation information for modulation, and the output is coupled into the optical fiber. The structure can be rotated without restriction through the multi-input and multi-output smooth ring. 3. N beams of sub-beams are emitted by their respective collimators. The angle information of each collimator is adjusted according to the approximate distance of the target and the power density requirements. Under normal circumstances, the angle adjusted by the control component will be symmetrical with the central rotation axis. At this time, n beams of tangential linearly arranged light cross sections will be formed at a certain distance away, rotating around the central rotation axis to form a scanning area S1, such as Figure 3 As shown; 4. When the sub-beam is scanned to Figure 3 The reflecting prism on target A shown in the figure will return the sub-beam along the original optical path. When the detector at the transmitting end receives the beam information, it will demodulate the unique characteristic information in the return light signal. The calculation unit will combine the detector information, the rotation structure information, and the angle information of the collimator to perform pointing solution and obtain the relative pitch angle and azimuth angle of target A.

[0085] Next, by Figure 4 The above settlement process is described in the structural diagram with the establishment of coordinate system analysis. Figure 4 As shown, the calibration places the rotating structure horizontally as the initial state, and the rotating structure rotates around the rotation center, and at this point Establishing the global coordinate system Take the front of the turntable as The positive direction of the axis, take the right side as The positive direction of the axis is Z' axis. In the initial state, the rotating structure is located in the coordinate system of Surface, also a rotating structure and Positive axis angle When it is 0°; take the rotating structure around When the shaft rotates The angle between the positive axis and the Take n collimators along The axes are arranged at a certain distance and marked as T1, T2, T3, T4 respectively, which can be represented by Tn (n=1,2,3,4). The angle between the positive axis direction (1, 0, 0) is ,like Figure 6 As shown, Figure 6 Schematic diagram of the coordinates of the rotating structure and the collimator in the embodiment of the present invention. After receiving the return light according to the present method, the target A is at a distance L in the direction of the collimator emitted by the characteristic light beam scanning the target A.

[0086] From this, the orientation can be solved as follows: Taking into account the main existing errors, the collimator position is calculated:

[0087] in, represents the collimator position, For the rotating structure The included angle in the positive direction of the axis, n represents the number of sub-beams, Represents the rotation angle error. The beam pointing direction of the sub-beam is:

[0088] in, represents the actual beam pointing direction of the sub-beam. The actual position of the target object is:

[0089] in, Indicates the actual position of the target object. The pitch angle of the target object is:

[0090] in, Indicates the actual pitch angle of the target object. The actual azimuth angle of the target object is:

[0091] in, Indicates the actual azimuth of the target object. Thus, the relevant data of the pitch angle and azimuth of the target object relative to the coordinate system S' can be determined.

[0092] In order to verify the relevant optimization indicators of this method, this method is compared with spiral scanning, such as Figure 7 As shown, Figure 7 This is a schematic diagram comparing spiral scanning and scanning using this method. Figure 7 In the figure, the left side shows the spiral scanning method which is frequently used in existing scanning methods, and the right side shows the multi-beam linear arrangement scanning method used in this method. They are calibrated to scan in the same size uncertainty area S. The spiral scanning method uses a single spot. Perform an Archimedean spiral scan around the uncertainty region S, gradually expanding from the center to the outside. The scan shown in this method is a tangentially arranged scanning section formed by n beams of light, which rotates around the center of the uncertainty region S. The angular velocity of their rotation is calibrated as The parameters of the comparative analysis experiment are calibrated as follows: Scan the uncertainty area S with a radius of R, i.e., the area is , the single spot diameter is D.

[0093] Taking n=4 as an example, this method uses a scanning method where four light spots are arranged along radius R and rotate around the center of the circle. With each rotation, the four light spots sweep through four concentric rings, covering the entire circular area S. Since 4D = R, the arrangement of the four light spots exactly matches the radius length, and theoretically, a single rotation can scan the entire circular area. The time required to complete a scan is:

[0094] Among them, T multi represents the scan time of this method, Therefore, this method only needs to complete one scan, which takes a short time.

[0095] Archimedean spiral scanning, a single spot starts from the center of the circle and scans outward along the spiral line, the spacing between adjacent spiral lines is , gradually covering the entire circular area. The path length of the spiral scan is approximately The linear velocity of the light spot is , where r represents the radius of rotation during the Archimedean spiral scanning process, that is, the distance between the scanning starting point and the current scanning point, and r changes from 0 to R, and the average speed is , the scan time is:

[0096] Among them, T spiral represents the scanning time of Archimedean spiral scanning, L pathrepresents the scanning path length, v represents the linear velocity of the light spot, is the angular velocity of rotation. Compared with the scanning time of this method, the spiral scanning time is When hour, That is, under the premise of the same uncertainty area and the same angular velocity, the scanning time of the Archimedean spiral scanning is theoretically about 4 times that of the present method.

[0097] This demonstrates that the scanning time of this method is significantly shorter than that of Archimedean spiral scanning, demonstrating a significant improvement in scanning efficiency. Other similar scanning methods (e.g., raster scanning, rosette scanning, Lissajous scanning, etc.) can be compared using this comparative model to derive data, and the results demonstrate that this application offers a clear advantage in scanning efficiency.

[0098] In order to verify the scanning accuracy of this method, a comparative analysis is performed using linear laser rapid scanning as an example: Figure 8 This is a schematic diagram comparing this method with linear laser rapid scanning, as shown in Figure 8 As shown, take the same uncertain scanning area S u , the radius is , the distance from the exit end of the sub-beam to the target B is , take the target B in the circular uncertain scanning area as Figure 8 As shown, the polar coordinates of target B are expressed as ,in , In this comparative experiment, the positioning error is the error in the position of target B calculated by the return light signal.

[0099] In the linear laser rapid scanning, the rectangular spot size is , where the long side is , the short side is The beam shown has no characteristic information (wavelength, frequency and other characteristics are consistent), and the source of the return light cannot be distinguished. The projected length on the scanning surface is equal to the radius of the scanning area ,Right now . Short side of rectangular spot The projection length on the scanning surface is equal to the diameter of a single spot of a single sub-beam on the scanning surface of this method. ,Right now , the angle error of the controlled rotation is .

[0100] In the spot error part, the position of target B is estimated as the spot center The maximum error is the boundary case, where the target is at the edge of the light spot, and the error is:

[0101]

[0102] in, It means that when target B is scanned, it is determined that target B is within the entire spot area, but its exact position cannot be determined. The maximum positioning error in the axis direction, represents the long side of the rectangular spot, Represents the short side of the rectangular spot, It means that when target B is scanned, it is determined that target B is within the entire spot area, but its exact position cannot be determined. The maximum positioning error in the axial direction, R represents the radius of the scanning area, and d represents the diameter of a single spot. The expression of the total spot error (Euclidean distance) is as follows:

[0103] in, Indicates the total spot error.

[0104] In the rotation angle error, the center position of the spot is determined by the rotation angle Determine that the center of the light spot moves along the rotation trajectory, and the trajectory radius is , the location of target B . Rotation angle error The actual rotation angle that causes position deviation is:

[0105] in, Indicates the actual rotation angle, represents the ideal rotation angle, Indicates the rotation angle error. The angle deviation is as follows:

[0106]

[0107] in, Indicates the position of the actual target B relative to the calculated target B. The difference angle in the axis direction, r c Indicates the distance between the target B position and the rotation center, Indicates the position of the actual target B relative to the calculated target B. The difference angle in the axis direction. The expression of the total angle error is as follows:

[0108] in, Indicates the total angle error. Combining the total spot error and the total angle error, the total positioning error is as follows:

[0109] in, Represents the total positioning error.

[0110] In this method, four sub-beams are taken and the control element is adjusted to control the collimator output angle so that the scanning surface reaches the target distance. Figure 8 As shown, each sub-beam is added with characteristic information (such as different wavelengths, frequencies, etc.) through the laser modulation unit, and the source can be identified by the return light. The four collimators are calibrated as T1, T2, T3, and T4. The length of the spot arrangement of the emitted sub-beam reaching the scanning surface is equal to the radius of the scanning area. The spot diameter of each beam is . Rotating structure around Axis rotation, rotation error angle error is The output angle of each sub-beam is adjusted by the collimator control component. , the control error is .

[0111] The pitch angle error is derived from the above and azimuth error , and then the position deviation is obtained as follows:

[0112]

[0113]

[0114] in, Indicates the pitch angle position deviation, Indicates the azimuth position deviation, Represents the total positioning error.

[0115] In summary, the error source of linear laser rapid scanning is mainly due to the spot error. and rotation angle error Due to the lack of feature information, spot error is inevitable, and the error is mainly caused by the long side. This method uses a scanning beam with feature information. Compared with the spot error in the linear laser scanning method, it eliminates the spot error and has a higher precision positioning and pointing capability; and the error source is the rotation error and control error . By comparing the results of the error formula, the positioning error of the linear laser scanning system is subject to the dual limitations of the spot size and the rotation error. The error is large and difficult to optimize. The positioning error of this method is only affected by the control angle error. Thanks to the optical signal characteristic information added by the laser modulation unit, it can accurately identify the source of the return light, greatly reducing the impact of the spot size on the positioning accuracy. Scanning methods such as increasing the spot size or increasing the beam divergence angle to improve scanning efficiency can be compared to this type of model. Therefore, this method has significant advantages in positioning accuracy, especially in long-distance or large-scale scanning scenarios, and can achieve more accurate target positioning, which is suitable for high-precision application requirements.

[0116] The present invention further provides an optical scanning target positioning system. The optical scanning target positioning system provided by the present invention is described below. The optical scanning target positioning system described below and the optical scanning target positioning method described above can be referenced to each other. The system includes: a laser generating unit, for generating a laser beam; A laser beam splitting unit, used for splitting the laser beam into several sub-beams; A laser modulation unit, used to modulate the corresponding sub-beams and distinguish different sub-beams; A beam emitting unit, configured to emit the modulated sub-beam at a specific beam divergence angle to form a scanning light spot; the beam emitting unit includes a collimator; A beam angle adjustment unit is used to control the rotation of the collimator to form a scanning area; The light receiving unit is used to receive the return light signal of the sub-beam reflected by the reflective prism on the target object, and determine the position information of the target object based on the return light signal.

[0117] In some embodiments, the laser generating unit includes a semiconductor laser, the laser light generated by the semiconductor laser having a wavelength of 850 nm to 1550 nm; the laser beam splitting unit includes a fiber beam splitter; and the laser modulation unit includes an optical modulator for modulating the sub-beams, wherein the modulation parameters include one or more of amplitude, carrier frequency, and phase.

[0118] In some embodiments, the system further includes a smooth ring located between the laser modulation unit and the beam emitting unit, and the smooth ring is used to assist in controlling the rotation of the collimator.

[0119] In some embodiments, the beam angle adjustment unit includes a rotating structure and a collimator angle control component; the rotating structure is used to control the synchronous rotation of all collimators; an angle sensor is provided on the rotating structure to obtain angle information of the collimator; the collimator angle control component is used to independently adjust the pointing angle of each collimator according to the distance of the target object.

[0120] For example, Figure 9 As shown, Figure 9 The present invention is a schematic diagram of an optical scanning target positioning system, which includes a semiconductor laser for generating laser light of a desired power; an optical fiber beam splitter for splitting the laser light generated by the laser into n laser beams; n optical modulators for modulating the intensity of the n sub-beams separated from the optical fiber beam splitter so that the n sub-beams have distinguishable beam characteristic information; n collimators for producing n sub-beams with the same power, the same beam divergence angle, and distinguishable information; n collimator control elements for adjusting the angles of the collimators, providing rotation angle information when calculating the pointing direction, and dynamically adjusting the scanning surface according to the approximate distance to the target to improve accuracy or increase the scan miss rate; a rotating structure for rotating the n collimators about a central axis; a collimator angle control element for independently adjusting the pointing angle of the collimators according to different target distances; an angle sensor mounted on the rotating structure for rotating the structure about the central axis and reading the rotation angle information for partial pointing data calculation; and a smooth ring for allowing the optical fiber modulated by the optical modulator to rotate freely with the rotating structure. It is worth noting that this system provides a method for processing n sub-beams in frequency modulation, which is not the only form. The number of beams and modulation information can be adjusted as needed.

[0121] By incorporating independently adjustable beam emission units, this system achieves dynamic optimization of sub-beams at varying target distances. The system adjusts the beam's angle of emission based on the target's specific distance, ensuring the beam's effective coverage of the scanned area is always maximized. This adaptability ensures optimal scanning coverage in diverse scenarios, enhancing the technology's flexibility and applicability, making it suitable for scanning tasks in a variety of complex environments.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An optical scanning target positioning method, characterized in that: include: Turning on the laser to generate a laser beam, and dividing the laser beam into a plurality of sub-beams through a fiber optic beam splitter; Modulating the sub-beams through an optical modulator and outputting them to a corresponding collimator; Based on the distance and power density requirements of the target object, the angle information of the collimator is adjusted, and the collimator is controlled to rotate to form a scanning area; the collimator is rotated by a rotating structure, and a reflective prism is pre-set on the target object; A return light signal generated when the sub-beam is reflected by a reflective prism on the target object is received, and position information of the target object is determined based on the return light signal.

2. The optical scanning target positioning method according to claim 1, characterized in that: The sub-beam is modulated by an optical modulator and output to a corresponding collimator, including: Each of the sub-beams enters a different optical modulator for modulation, and the modulation parameters include one or more of amplitude, carrier frequency and phase; The modulated sub-beam is output-coupled into an optical fiber and passes through a smooth ring into the corresponding collimator; the smooth ring is used to assist in controlling the rotation of the collimator.

3. The optical scanning target positioning method according to claim 1, characterized in that: In the scanning area, the sub-beams are adjacent to each other and arranged linearly, and the sum of the diameters of the sub-beams is equal to the radius of the scanning area.

4. The optical scanning target positioning method according to claim 1, characterized in that: Receiving a return light signal of the sub-beam reflected by a reflective prism on the target object, and determining position information of the target object based on the return light signal, comprising: When the sub-beam scans the target object, the reflective prism on the target object returns the sub-beam along the original optical path; The detector at the transmitting end receives the return light signal of the sub-beam and determines the relative pitch angle and azimuth angle of the target object based on the return light signal.

5. The optical scanning target positioning method according to claim 4, characterized in that: The transmitting end detector receives the return light signal of the sub-beam, and determines the relative pitch angle and azimuth angle of the target object based on the return light signal, including: The transmitter detector demodulates the unique characteristic information in the return light signal; The unique feature information, detector information, rotation structure information and angle information of the collimator are comprehensively used to perform a pointing solution to obtain the relative pitch angle and azimuth angle of the target object.

6. An optical scanning target positioning system, used to implement the optical scanning target positioning method according to any one of claims 1 to 5, characterized in that: include: a laser generating unit, for generating a laser beam; a laser beam splitting unit, configured to split the laser beam into a plurality of sub-beams; a laser modulation unit, configured to modulate the sub-beams and distinguish different sub-beams; a beam emitting unit, configured to emit the modulated sub-beam at a specific beam divergence angle to form a scanning light spot; the beam emitting unit comprising a collimator; A beam angle adjustment unit, used to control the rotation of the collimator to form a scanning area; The light receiving unit is configured to receive a return light signal generated when the sub-beam is reflected by a reflective prism on the target object, and determine position information of the target object based on the return light signal.

7. The optical scanning target positioning system according to claim 6, characterized in that: The laser generating unit includes a semiconductor laser, and the wavelength of the laser light generated by the semiconductor laser is 850nm-1550nm; the laser beam splitting unit includes a fiber beam splitter.

8. The optical scanning target positioning system according to claim 6, characterized in that: The laser modulation unit includes a light modulator; Used to modulate the sub-beam, the modulation parameters include one or more of amplitude, carrier frequency and phase.

9. The optical scanning target positioning system according to claim 6, characterized in that: The system further includes a smooth ring located between the laser modulation unit and the beam exit unit, and the smooth ring is used to assist in controlling the rotation of the collimator.

10. The optical scanning target positioning system according to claim 6, characterized in that: The beam angle adjustment unit includes a rotating structure and a collimator angle control member; The rotating structure is used to control the synchronous rotation of all collimators; an angle sensor is provided on the rotating structure to obtain angle information of the collimators; The collimator angle control member is used to independently adjust the pointing angle of each collimator according to the distance of the target object.

Images