Laser tracking interferometry spatial coordinate measurement system and method based on dual electro-optic frequency combs

Abstract

The application discloses a laser tracking interference space coordinate measurement system and method based on a double electro-optical frequency comb. A visual module is used to identify multiple target mirrors, and a rotating mirror is used to guide laser to point to each target mirror. A laser tracking interference distance measurement module obtains tracking error of laser beam deviating from the center of the target mirror, which is used for closed-loop tracking control. A light source module outputs single-frequency laser traced to a gas absorption peak. A light source modulation module is controlled to open or close an electro-optical phase modulation driving signal, and double electro-optical frequency combs and double-frequency continuous laser are output. In a tracking state, the laser tracking interference distance measurement module uses the two kinds of light sources to measure the absolute distance and relative displacement of the target mirror, and the real-time distance of the target mirror and the origin is obtained through distance fusion calculation. The azimuth angle and the elevation angle of the target mirror are obtained in real time through an azimuth angle and an elevation angle measurement module. Tracking control and coordinate calculation are performed through a tracking control and signal processing module and a computer, and finally the three-dimensional space coordinates of all target mirrors are measured.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of laser tracking measurement, and particularly relates to a laser tracking interference spatial coordinate measurement system and method based on a double electro-optic frequency comb. BACKGROUND

[0002] The laser tracking interference measurement technology is widely applied to large-size high-end equipment assembly, industrial robot positioning precision calibration and other fields due to the advantages of large measurement range, high precision and fast speed.

[0003] Distance measurement is the core technology of laser tracking interference measurement. The existing laser tracking interference measurement method usually adopts two ranging methods of absolute distance measurement (ADM) and relative displacement measurement (RDM) to combine measurement. The ADM method can obtain absolute distance and can recover measurement after light interruption, but is only suitable for static measurement. The RDM method can realize high-speed displacement measurement, but the measurement result is displacement increment, and light interruption will lead to measurement failure. The combined measurement method combines the advantages of the two measurement methods, but needs to combine the measurement light of the two measurement units into a laser for measurement. When the mechanical parts for fixing the optical elements slowly deform over time, the combined light beam will bifurcate, thereby introducing measurement error. On the other hand, the two ranging units have different distance reference zero points, which may introduce additional drift error and increase the system complexity and cost.

[0004] Therefore, the existing technology lacks the use of the same ranging unit to construct the ADM and RDM ranging modes to realize high-precision absolute distance measurement, which is a technical problem that has not been solved in the field of laser tracking interference measurement. SUMMARY

[0005] In order to solve the problems in the background art, the application discloses a laser tracking interference spatial coordinate measurement system and method based on a double electro-optic frequency comb, which realizes the ADM and RDM ranging functions by using a single ranging module based on a double electro-optic frequency comb.

[0006] The technical scheme adopted by the application to solve the technical problems is:

[0007] I. A laser tracking interference spatial coordinate measurement system based on a double electro-optic frequency comb:

[0008] The application is divided into three parts: a precise optical tracking unit, a ranging unit based on a double electro-optical frequency comb, and an electric control unit; one part of the precise optical tracking unit is installed on the frame machine body, and the other part is installed on the measured object or space; the ranging unit is installed in the frame machine body; the electric control unit is electrically connected with the precise optical tracking unit and the ranging unit; the electric control unit controls the ranging unit based on the double electro-optical frequency comb to emit a double electro-optical frequency comb light beam, which is reflected by the precise optical tracking unit, adjusted to be incident on the measured object or space, and then received to measure the spatial coordinates of the measured object or space.

[0009] The precise optical tracking unit mainly comprises a target mirror group, a rotating mirror, a pitch torque motor, a vision module, a pitch angle measurement module, an azimuth torque motor, and an azimuth angle measurement module; the target mirror group is arranged on the measured object or in the measured space; the azimuth torque motor is installed on the upper end of the frame machine body; a horizontal and parallel rotating mirror shaft and a vision shaft are installed on the rotating end of the azimuth torque motor through a support; the rotating end of the azimuth torque motor is provided with an azimuth angle measurement module for detecting the rotation angle; one end of the rotating mirror shaft is coaxially fixedly connected with the rotating end of the pitch torque motor; the other end of the rotating mirror shaft is connected with the pitch angle measurement module for measuring the rotation angle of the rotating mirror shaft; the rotating mirror is fixedly installed on the rotating mirror shaft; the vision shaft is rotatably installed on the support through a gear set; and the vision module is fixedly installed on the vision shaft.

[0010] The ranging unit based on the double electro-optical frequency comb comprises, from bottom to top, a light beam adjustment module, a laser tracking interference ranging module, a light source modulation module, and a light source module.

[0011] The light source module outputs single-frequency laser traced to a gas absorption peak; the single-frequency laser is transmitted to the light source modulation module through a polarization maintaining optical fiber to generate a double electro-optical frequency comb after electro-optical phase modulation; the double electro-optical frequency comb is transmitted to the laser tracking interference ranging module; the laser tracking interference ranging module outputs measurement light to the light beam adjustment module; the measurement light is expanded and collimated by the light beam adjustment module, and then adjusted by translation and deflection control, so that the measurement light is incident on the center of the rotating mirror, and then reflected by the rotating mirror to be incident on the target mirror group of the measured object or space, and then returned to the laser tracking interference ranging module after being reflected by the target mirror group.

[0012] The pitch torque motor, the vision module, the pitch angle measurement module, the azimuth torque motor, and the azimuth angle measurement module in the precise optical tracking unit are electrically connected through a coaxial conductive ring provided on the upper end of the frame machine body.

[0013] The electric control unit mainly comprises a power module, a tracking control and signal processing module, and a computer; the tracking control and signal processing module is electrically connected with the computer; the power module is connected with the tracking control and signal processing module for power supply; and the tracking control and signal processing module is electrically connected with the precise optical tracking unit and the ranging unit.

[0014] The environmental monitoring sensor is electrically connected with the tracking control and signal processing module of the electric control unit, and is used for measuring temperature, humidity and air pressure parameters of air and transmitting the parameters to the tracking control and signal processing module through wireless transmission.

[0015] The tracking control and signal processing module of the electric control unit processes and outputs a closed-loop control signal according to target mirror information in the image obtained by the visual module and a tracking error signal obtained by the laser tracking interference distance measuring module, so as to control the azimuth torque motor and the elevation torque motor to jointly rotate the target mirror.

[0016] The laser tracking interference distance measuring module comprises a laser diode, a polarization-maintaining fiber combiner, a first collimator, a first polarization beam splitter, a reference corner cube prism, a filter, a first quarter-wave plate, a second quarter-wave plate, a second collimator, a dichroic filter, a second polarization beam splitter, a first photodetector, a second photodetector, a two-dimensional position detector and a right-angle reflector, which are installed in a shielding shell.

[0017] The second combined light is formed after the second reflection and the second transmission of the light beams that are combined again, and the second combined light is incident on the dichroic filter again to be transmitted and reflected, the light beam reflected by the dichroic filter is incident on the two-dimensional position detector to obtain a tracking error signal, and the light beam transmitted by the dichroic filter is incident on the second polarizing beam splitter again to be reflected and transmitted; the reference light in the double electro-optical frequency comb is emitted by the ranging unit, expanded and collimated by the second collimator, and then incident on the second polarizing beam splitter to be reflected and transmitted, the light beam reflected by the second polarizing beam splitter and the light beam transmitted by the second polarizing beam splitter are incident on the first photodetector together to obtain a reference interference signal, and the light beam transmitted by the second polarizing beam splitter and the light beam reflected by the second polarizing beam splitter are incident on the second photodetector together to obtain a measurement interference signal.

[0018] The tracking control and signal processing module comprises an image processing module, a tracking error signal preprocessing module, an angle decoding module, a tracking control module, a motor driver, a synchronization module and a signal processing module, and the signal processing module comprises an absolute distance measurement signal processing module, an air refractive index calculation module, a relative displacement measurement signal processing module and a distance fusion module;

[0019] The input ends of the image processing module, the tracking error signal preprocessing module and the angle decoding module are electrically connected with the vision module, the two-dimensional position detector and the azimuth angle measurement module respectively, the input ends of the absolute distance measurement signal processing module and the relative displacement measurement signal processing module are electrically connected with the first photodetector and the second photodetector, the input end of the air refractive index calculation module is electrically connected with the environment monitoring sensor, and the output end of the air refractive index calculation module is also connected to the absolute distance measurement signal processing module and the relative displacement measurement signal processing module; the absolute distance measurement signal processing module and the relative displacement measurement signal processing module both have three input ends, and the three input ends are the first photodetector, the second photodetector and the air refractive index calculation module.

[0020] The output ends of the absolute distance measurement signal processing module and the relative displacement measurement signal processing module are connected to the distance fusion module, the output ends of the image processing module, the tracking error signal preprocessing module, the angle decoding module and the distance fusion module are all connected to the tracking control module at the same time, and the output end of the tracking control module is connected to the azimuth torque motor and the pitch torque motor through the motor driver;

[0021] The output ends of the angle decoding module and the distance fusion module are both connected to the synchronization module, and the output end of the synchronization module is connected to the computer.

[0022] II. A method for laser tracking interference spatial coordinate measurement and control based on a double electro-optical frequency comb:

[0023] 1) The light source module outputs a single-frequency laser sourced from the gas absorption peak. The single-frequency laser is transmitted to the light source modulation module through a polarization-maintaining fiber for electro-optic phase modulation, generating a dual electro-optic frequency comb. The dual electro-optic frequency comb is transmitted to the laser tracking interferometric ranging module. The laser tracking interferometric ranging module outputs measurement light, which is transmitted to the beam adjustment module. The beam adjustment module expands and collimates the measurement light, and then adjusts it through translation and deflection control, so that the measurement light is incident on the center of the rotating mirror parallel to the direction of gravity. After being reflected by the rotating mirror, it is incident on the target mirror of the target mirror group of the object to be measured or the space to be measured. After being reflected by the target mirror of the target mirror group, it returns to the laser tracking interferometric ranging module to receive and obtain the tracking error signal, reference interference signal, and measurement interference signal in real time, which are then used to realize distance measurement and tracking error acquisition.

[0024] One path of the dual electro-optic frequency comb is used as the measurement light, and the other path of the dual electro-optic frequency comb is used as the reference light after being frequency-shifted by acousto-optic modulation. Both the reference light and the measurement light are transmitted to the laser tracking interferometric ranging module through polarization-maintaining fiber.

[0025] Then, in the laser tracking interferometric ranging module, the measurement light is combined with the indicator light output from the laser diode through a polarization-maintaining fiber combiner; the measurement light and the reference light are expanded and collimated by the first collimator and the second collimator, respectively. Both the measurement light and the reference light are divided into p-polarized and s-polarized components.

[0026] The p-polarized component of the measurement light is transmitted through the first polarizing beam splitter, then output to the beam adjustment module via the second quarter-wave plate, right-angle mirror, and window, and returns after reflection by the rotating mirror and target mirror. The s-polarized component of the measurement light is reflected by the first polarizing beam splitter, then reflected by the first quarter-wave plate, filter, and reference corner cube prism before returning. The two returning measurement beams are first processed by a dichroic filter to undergo transmission and reflection. The indicator light reflected by the dichroic filter is transmitted to the two-dimensional position detector to obtain a tracking error signal for tracking control. The measurement light transmitted by the dichroic filter is reflected and transmitted at the second polarizing beam splitter. The s-polarized component of the reference light is reflected by the second polarizing beam splitter, and then, together with the p-polarized component of the measurement light transmitted by the dichroic filter, is sent to the first photodetector to obtain a reference interference signal. The p-polarized component of the reference light is transmitted through the second polarizing beam splitter, and then, together with the s-polarized component of the measurement light reflected by the dichroic filter, is sent to the second photodetector to obtain a measurement interference signal. The reference interference signal and the measurement interference signal are used for distance measurement.

[0027] 2) The modulation of the light source modulation module is controlled to turn on and off, and then the absolute distance and relative displacement are measured by the laser tracking interferometric ranging module in absolute ranging mode and relative displacement mode, respectively.

[0028] In the absolute distance measurement mode, the light source modulation module outputs a dual electro-optical frequency comb, and the first photodetector and the second photodetector of the laser tracking and interferometric distance measurement module obtain a reference multi-heterodyne interference signal and a measurement multi-heterodyne interference signal respectively, and the absolute distance can be obtained through signal processing;

[0029] In the relative displacement measurement mode, the light source modulation module outputs a dual-frequency continuous laser with a frequency difference of Fa, and the first photodetector and the second photodetector of the laser tracking and interferometric distance measurement module obtain a reference heterodyne interference signal and a measurement heterodyne interference signal respectively, and the relative displacement can be obtained through signal processing.

[0030] Meanwhile, the air parameter signal is measured by the environmental monitoring sensor, which is used for air refractive index compensation of the distance measurement module, the angle measurement signals of the elevation angle and the azimuth angle of the rotating mirror in the tracking state are obtained in real time by the elevation angle measurement module and the azimuth angle measurement module of the precision optical tracking unit, and the picture image of the target mirror group in the tracking state is obtained in real time by the vision module of the precision optical tracking unit;

[0031] 3) The tracking error signal, the reference interference signal, the measurement interference signal, the air parameter signal, the angle measurement signal, the picture image, the absolute distance and the relative displacement are all input into the tracking control and signal processing module for processing, the rotation control of the elevation torque motor and the azimuth torque motor is controlled to control the rotation of the rotating mirror, and the closed-loop tracking of the target mirror of the target mirror group is realized, and the angle information and the distance information are converted into three-dimensional space coordinates for display.

[0032] The step 3) is performed in the tracking control and signal processing module,

[0033] The air parameter signal, the reference interference signal, the measurement interference signal and the angle measurement signal are transmitted to the tracking control and signal processing module for processing, the angle information is obtained by decoding the angle measurement signal in the angle decoding module, the distance information is obtained by processing and compensating the reference interference signal and the measurement interference signal in the signal processing module using the air parameter signal, the position deviation information of the measurement light spot and the target mirror center is obtained by processing the tracking error signal in the tracking error signal preprocessing module, and the identification information of all target mirrors is obtained by processing the picture image in the image processing module.

[0034] On the one hand, the identification information, the position deviation information, the angle information and the distance information of all target mirrors are transmitted to the tracking control module, the feedback control signal is obtained by processing through the closed-loop control algorithm, and the rotating mirror is controlled to rotate by transmitting the feedback control signal to the elevation torque motor and the azimuth torque motor through the motor driver, so that the closed-loop tracking of the target mirror is realized.

[0035] On the other hand, the synchronization module is used to synchronize the angle information and the distance information to eliminate the time delay between the angle information and the distance information, and then the synchronized angle information and distance information are transmitted to a computer to convert and display the three-dimensional space coordinates, and finally the three-dimensional space coordinates of all target mirrors are measured.

[0036] After the above processing, the absolute distance measurement and relative displacement measurement functions and the laser tracking error detection function can be realized by using only a single laser tracking interferometric distance measurement module, and the optical system is simplified.

[0037] In the specific implementation, the pitch torque motor control signal, the vision module signal and the pitch angle / azimuth angle measurement module signal are transmitted to the frame body through the coaxial conductive ring, so that the cable winding problem during rotation can be avoided, and the rotation can be unlimited.

[0038] In the system, the vision module is used to identify multiple target mirrors, and the rotating mirror is guided to direct the laser to each target mirror. The laser tracking interferometric distance measurement module obtains the tracking error of the laser beam deviating from the center of the target mirror, which is used for closed-loop tracking control. The light source module outputs single-frequency laser traced to the gas absorption peak. By controlling the light source modulation module to turn on or off the electro-optic phase modulation driving signal, double electro-optic frequency combs and double-frequency continuous laser are output respectively. In the tracking state, the laser tracking interferometric distance measurement module uses the two kinds of light sources to measure the absolute distance and relative displacement of the target mirror, and the real-time distance of the target mirror from the origin is obtained through distance fusion calculation. The azimuth angle and pitch angle measurement module is used to obtain the pitch angle and azimuth angle of the target mirror in real time. Through the tracking control and signal processing module and the computer, tracking control and three-dimensional space coordinate calculation are performed, and finally the three-dimensional space coordinates of all target mirrors are measured.

[0039] In the system, the vision module is used to identify multiple target mirrors, and the rotating mirror is guided to direct the laser to each target mirror. The laser tracking interferometric distance measurement module obtains the tracking error of the laser beam deviating from the center of the target mirror, which is used for closed-loop tracking control. The light source module outputs single-frequency laser traced to the gas absorption peak. By controlling the light source modulation module to turn on or off the electro-optic phase modulation driving signal, double electro-optic frequency combs and double-frequency continuous laser are output respectively. In the tracking state, the laser tracking interferometric distance measurement module uses the two kinds of light sources to measure the absolute distance and relative displacement of the target mirror, and the real-time distance of the target mirror from the origin is obtained through distance fusion calculation.

[0040] In the system, the vision module is used to identify multiple target mirrors, and the rotating mirror is guided to direct the laser to each target mirror. The laser tracking interferometric distance measurement module obtains the tracking error of the laser beam deviating from the center of the target mirror, which is used for closed-loop tracking control. The light source module outputs single-frequency laser traced to the gas absorption peak. By controlling the light source modulation module to turn on or off the electro-optic phase modulation driving signal, double electro-optic frequency combs and double-frequency continuous laser are output respectively. In the tracking state, the laser tracking interferometric distance measurement module uses the two kinds of light sources to measure the absolute distance and relative displacement of the target mirror, and the real-time distance of the target mirror from the origin is obtained through distance fusion calculation.

[0041] The system of the present application can be used in the scenes of robot calibration and part measurement.

[0042] The present application has the beneficial effects that:

[0043] (1) The present application adopts a single ranging module based on a double electro-optical frequency comb to realize the functions of absolute ADM and RDM ranging and laser tracking error detection, which can simplify the system structure, reduce the cost and avoid the measurement errors caused by beam bifurcation and different distance zero points;

[0044] (2) The visual module of the present application adopts a gear linkage mode for field of view control, which can ensure that the target mirror is always in the middle region of the field of view, and is conducive to multi-mirror identification and tracking control;

[0045] (3) The present application adopts a frame type body design to integrate related modules, which is conducive to assembly and debugging, and adopts a coaxial conductive ring to transmit signals, which can avoid cable winding problems during rotation and can rotate unlimitedly. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 is a schematic diagram of a laser tracking interference space coordinate measurement system based on a double electro-optical frequency comb.

[0047] Figure 2 is a principle block diagram of laser tracking interference ranging based on a double electro-optical frequency comb.

[0048] Figure 3 is a principle block diagram of tracking control and signal processing.

[0049] In the figure: 1, target mirror group, 101, target mirror, 2, environmental parameter monitoring sensor, 3, frame body, 4, rotating mirror, 5, pitch torque motor, 6, gear set, 7, visual module, 8, pitch angle measurement module, 9, coaxial conductive ring, 10, azimuth torque motor, 11, azimuth angle measurement module, 12, beam adjustment module, 13, laser tracking interference ranging module, 14, light source modulation module, 15, light source module, 16, power module, 17, tracking control and signal processing module, 18, computer.

[0050] 1302, optical fiber flange group, 1303, laser diode, 1304, optical fiber polarization maintaining beam combiner, 1305, first collimator, 1306, first polarization beam splitter, 1307, reference corner cube prism, 1308, optical filter, 1309, first quarter wave plate, 1310, second quarter wave plate, 1311, window sheet, 1313, cable shielding interface, 1314, second collimator, 1315, dichroic sheet, 1316, second polarization beam splitter, 1317, first photodetector, 1318, second photodetector, 1319, two-dimensional position detector, 1320, right-angle reflector, 1321, shielding shell.

[0051] 1701, image processing module, 1702, tracking error signal preprocessing module, 1703, angle decoding module, 1704, absolute distance measurement signal processing module, 1705, air refractive index calculation module, 1706, relative displacement measurement signal processing module, 1707, tracking control module, 1708, motor driver, 1709, synchronization module, 1710, distance fusion module, 1711, signal processing module. DETAILED DESCRIPTION

[0052] The application will be described in detail below with reference to the accompanying drawings and examples.

[0053] As shown in the figure, the laser tracking interference space coordinate measurement system based on double electro-optical frequency comb is specifically: Figure 1 The whole device is divided into three parts: a precise optical tracking unit, a distance measuring unit based on a double electro-optical frequency comb, and an electric control unit. One part of the precise optical tracking unit is installed on the frame body 3, and the other part is installed on the measured object or the measured space. The distance measuring unit is installed in the frame body 3, and the electric control unit is electrically connected with the precise optical tracking unit and the distance measuring unit. The electric control unit controls the distance measuring unit based on the double electro-optical frequency comb to emit a double electro-optical frequency comb light beam, which is reflected and adjusted by the precise optical tracking unit to be incident on the measured object or the measured space, and then receives the spatial coordinate measurement of the measured object or the measured space.

[0054] The precise optical tracking unit mainly includes a target mirror group 1, a rotating mirror 4, a pitch torque motor 5, a vision module 7, a pitch angle measurement module 8, an azimuth torque motor 10, and an azimuth angle measurement module 11.

[0055] The target mirror group 1 includes a plurality of target mirrors 101, and the target mirrors 101 of the target mirror group 1 are arranged on the measured object or in the measured space.

[0056] The azimuth torque motor 10 is installed on the upper end of the frame body 3, and a rotating mirror shaft and a vision shaft, both of which are horizontal and parallel, are installed on the rotating end of the azimuth torque motor 10 through a support. The rotating mirror shaft is rotatably installed on the support, and the support is fixed on the rotating end of the azimuth torque motor 10. At the same time, the rotating end of the azimuth torque motor 10 is provided with an azimuth angle measurement module 11 for detecting the rotation angle. The rotating mirror shaft is driven by the azimuth torque motor 10 to rotate horizontally around the vertical shaft, and the horizontal rotation angle is measured by the azimuth angle measurement module 11.

[0057] The rotating mirror shaft is independently rotatably installed on the support, one end of the rotating mirror shaft is fixedly connected with the rotating end of the pitch torque motor 5, and the other end of the rotating mirror shaft is connected with the pitch angle measurement module 8 for measuring the rotation angle of the rotating mirror shaft. The rotating mirror 4 is fixedly installed on the rotating mirror shaft.

[0058]

[0059] ​The visual shaft is independently rotatably mounted on the support through the gear set 6, and the visual module 7 is fixedly mounted on the visual shaft.

[0060] The arrangement enables the rotating mirror 4 and the visual module 7 to independently rotate with the same degree of freedom.

[0061] The rotation shaft of the visual module 7 is parallel to the rotation shaft of the rotating mirror 4, and is linked through the gear set 6, and the rotation angle ratio of the elevation angle is 2:1, and in the tracking state, the target mirror is always located in the visual field of the visual module camera.

[0062] The ranging unit based on the double electro-optical frequency comb is the core part of the application, mainly comprising the light beam adjusting module 12, the laser tracking interference ranging module 13, the light source modulation module 14 and the light source module 15 arranged coaxially from bottom to top in sequence, and the modules are installed in the frame body 3 in layers.

[0063] The double electro-optical frequency comb is generated by the light source module 15 and the light source modulation module 14. The single-frequency laser outputted by the light source module 15 is transmitted to the light source modulation module 14 through the polarization maintaining optical fiber to generate the double electro-optical frequency comb after electro-optical phase modulation, and the double electro-optical frequency comb is transmitted to the laser tracking interference ranging module 13.

[0064] When the electro-optical phase modulation driving signal in the light source modulation module 14 is turned off, the non-zero order comb teeth of the double electro-optical frequency comb will disappear, and the double electro-optical frequency comb becomes double-frequency continuous laser.

[0065] In the light beam adjusting module 12, the measuring light is first expanded and collimated into a circular Gaussian beam with a diameter of 10 mm, and then adjusted by a translation and deflection control adjusting mirror, so that the measuring light is parallel to the direction of gravity and incident to the origin position of the rotation center of the rotating mirror 4, reflected by the rotating mirror 4 and the target mirror 1322, and returned to the laser tracking interferometric distance measuring module 13 to realize distance measurement and tracking error acquisition.

[0066] The electronic elements in the precision optical tracking unit, such as the pitch torque motor 5, the vision module 7, the pitch angle measuring module 8, the azimuth torque motor 10, and the azimuth angle measuring module 11, are connected to the electronic control unit by wires and the coaxial conductive ring 9 arranged at the upper end of the frame body 3. In this way, the electronic elements in the precision optical tracking unit and the frame body 3 are powered and signal transmitted through the coaxial conductive ring 9, without the need for cables, which can avoid cable winding problems during rotation and can rotate unlimitedly.

[0067] Moreover, the azimuth torque motor 10 and the azimuth angle measuring module 11 of the precision optical tracking unit are both annular structures with a central through hole, and the coaxial conductive ring 9 with a central through hole is arranged in the annular structure. The light beam emitted by the light beam adjusting module 12 transmits through the hollow central through hole of the azimuth torque motor 10, the azimuth angle measuring module 11, and the coaxial conductive ring 9 and then is incident on the rotating mirror 4.

[0068] The electronic control unit mainly includes a power module 16, a tracking control and signal processing module 17, and a computer 18. The tracking control and signal processing module 17 and the computer 18 are electrically connected, the power module 16 and the tracking control and signal processing module 17 are connected for power supply, and the tracking control and signal processing module 17 is electrically connected with the pitch torque motor 5, the vision module 7, the pitch angle measuring module 8, the azimuth torque motor 10, and the azimuth angle measuring module 11 of the precision optical tracking unit, the light beam adjusting module 12, the laser tracking interferometric distance measuring module 13, the light source modulation module 14, and the light source module 15 of the distance measuring unit.

[0069] It also includes an environmental monitoring sensor 2, which is electrically connected with the tracking control and signal processing module 17 of the electronic control unit. The environmental monitoring sensor 2 is used to measure the temperature, humidity, and air pressure parameters of the air and transmit them to the tracking control and signal processing module 17 wirelessly for air refractive index compensation in the laser tracking interferometric distance measuring module 13.

[0070] The tracking control and signal processing module 17 of the electric control unit processes the target mirror information in the image obtained by the vision module 7 and the tracking error signal obtained by the laser tracking interferometric distance measurement module 13, and outputs a closed-loop control signal to control the rotation of the target mirror 1 by the azimuth torque motor 10 and the elevation torque motor 5 in combination with the rotating mirror 4; at the same time, the azimuth angle measurement module 11 and the elevation angle measurement module 8 are used to obtain the angle information of the target mirror in the tracking state, and the distance information obtained by the laser tracking interferometric distance measurement module 13 is combined to match the angle information and the distance information, and the computer 18 is used for error compensation and coordinate conversion to obtain the three-dimensional coordinates of each target mirror 101 in the target mirror group 1.

[0071] Figure 2 The laser tracking interferometric distance measurement principle diagram based on the double electro-optical frequency comb is shown, which is a further description of the working principle of the laser tracking interferometric distance measurement module 13 in the laser tracking interferometric distance measurement module 13. Figure 1

[0072] The laser tracking interferometric distance measurement module 13 is closed and packaged by a shielding shell 1321, which can isolate air and avoid external interference.

[0073] The laser tracking interferometric distance measurement module 13 includes a laser diode 1303, a polarization-maintaining fiber combiner 1304, a first collimator 1305, a first polarization beam splitter 1306, a reference corner cube prism 1307, a filter 1308, a first quarter-wave plate 1309, a second quarter-wave plate 1310, a second collimator 1314, a dichroic filter 1315, a second polarization beam splitter 1316, a first photodetector 1317, a second photodetector 1318, a two-dimensional position detector 1319, and a right-angle reflector 1320, which are installed in the shielding shell 1321.

[0074] ​The light source modulation module 14 of the ranging unit emits the measurement light in the double electro-optical frequency comb and the indicating light emitted by the laser diode 1303 together into the polarization maintaining fiber combiner 1304 to form first combined light, and the first combined light is expanded and collimated by the first collimator 1305 and then incident to the first polarization beam splitter 1306 to undergo first transmission and reflection; the first combined light after the first reflection of the first polarization beam splitter 1306 is reflected by the first quarter-wave plate 1309, the filter 1308 and the reference corner cube prism 1307 in turn and then returns to the first polarization beam splitter 1306 in the original path to undergo second transmission; the first combined light after the first transmission of the first polarization beam splitter 1306 is reflected by the second quarter-wave plate 1310 and the right-angle reflector 1320 in turn and then exits the shielding shell 1321 through the window sheet 1311 and is incident to the target mirror 101 in the target mirror group 1 after being adjusted by the beam adjustment module 12, and then returns to the first polarization beam splitter 1306 in the original path after being reflected by the target mirror 101 in the target mirror group 1 to undergo second reflection.

[0075] The light beams after the second reflection and the second transmission of the first polarization beam splitter 1306 are combined to form second combined light, and the second combined light is incident to the dichroic sheet 1316 to undergo transmission and reflection, the light beams reflected by the dichroic sheet 1316 are incident to the two-dimensional position detector 1319 to obtain a tracking error signal, and the light beams transmitted by the dichroic sheet 1316 are incident to the second polarization beam splitter 1316 to undergo reflection and transmission respectively.

[0076] The reference light in the double electro-optical frequency comb emitted by the light source modulation module 14 of the ranging unit is expanded and collimated by the second collimator 1314 and then incident to the second polarization beam splitter 1316 to undergo reflection and transmission, the light beams reflected by the second polarization beam splitter 1316 and the light beams transmitted by the second polarization beam splitter 1316 together are incident to the first photodetector 1317 to obtain a reference interference signal, and the light beams transmitted by the second polarization beam splitter 1316 and the light beams reflected by the second polarization beam splitter 1316 together are incident to the second photodetector 1318 to obtain a measurement interference signal.

[0077] In specific implementation, the shielding shell 1321 is provided with the fiber flange group 1302, and the measurement light and the reference light in the double electro-optical frequency comb emitted by the light source modulation module 14 of the ranging unit are respectively incident to the shielding shell 1321 through different interface channels in the fiber flange group 1302.

[0078] In the embodiment, the two-dimensional position detector 1319, the first photoelectric detector 1317 and the second photoelectric detector 1318 are electrically connected to the signal processing module 1711 in the tracking control and signal processing module 17 of the electric control unit through the cable shielding interface 1313 provided on the shielding shell 1321, and the signal processing module 1711 in the tracking control and signal processing module 17 of the electric control unit is electrically connected to the light source module 15.

[0079] Specifically, in the laser tracking interferometric distance measurement module 13, the measurement light is combined with the indicating light output by the laser diode 1303 through the polarization maintaining fiber combiner 1304; the measurement light and the reference light are respectively expanded and collimated by the first collimator 1305 and the second collimator 1314. Both the measurement light and the reference light are divided into p-polarization state components and s-polarization state components.

[0080] The p-polarization state component in the measurement light is transmitted through the first polarization beam splitter 1306, then output to the beam adjustment module 12 through the second quarter-wave plate 1310, the right-angle mirror 1320 and the window sheet 1311, and returned after being reflected by the rotating mirror 4 and the target mirror 1322; the s-polarization state component in the measurement light is reflected by the first polarization beam splitter 1306, then returned after being reflected by the first quarter-wave plate 1309, the filter 1308 and the reference corner cube prism 1307; the two returned measurement lights are first processed by the dichroic sheet 1316 to be transmitted and reflected, the indicating light reflected by the dichroic sheet 1316 is transmitted to the two-dimensional position detector 1319 to obtain a tracking error signal for tracking control, and the measurement light transmitted by the dichroic sheet 1316 is reflected and transmitted at the second polarization beam splitter 1316; the s-polarization state component of the reference light is reflected by the second polarization beam splitter 1316, then transmitted to the first photoelectric detector 1317 together with the p-polarization state component of the measurement light transmitted by the dichroic sheet 1316 to obtain a reference interference signal; the p-polarization state component of the reference light is transmitted by the second polarization beam splitter 1316, then transmitted to the second photoelectric detector 1318 together with the s-polarization state component of the measurement light reflected by the dichroic sheet 1316 to obtain a measurement interference signal, and the reference interference signal and the measurement interference signal are used for distance measurement.

[0081] The first photoelectric detector 1317 and the second photoelectric detector 1318 are internally integrated with polarization sheets, and the transmission axis of the polarization sheet is 45° different from the p-polarization state of the second polarization beam splitter 1316.

[0082] The laser tracking interferometric distance measurement module 13 has both absolute distance measurement and relative displacement measurement functions, and simultaneously has a laser tracking error detection function.

[0083] In the absolute distance measurement mode, the light source modulation module 14 is controlled to open the electro-optical phase modulation and output a double electro-optical frequency comb, at this time, the first photodetector 1317 and the second photodetector 1318 of the laser tracking and interference distance measurement module 13 obtain a reference multi-heterodyne interference signal and a measurement multi-heterodyne interference signal respectively, and after signal processing, the absolute distance can be obtained.

[0084] In the relative displacement measurement mode, the light source modulation module 14 is controlled to close the electro-optical phase modulation and output a double-frequency continuous laser with a frequency difference of F a At this time, the first photodetector 1317 and the second photodetector 1318 of the laser tracking and interference distance measurement module 13 obtain a reference heterodyne interference signal and a measurement heterodyne interference signal respectively, and after signal processing, the relative displacement can be obtained.

[0085] The laser tracking error detection function can be simultaneously performed in the two distance measurement modes without interference. In the laser tracking error detection function, the returned indicating light is transmitted to the two-dimensional position detector 1319 to obtain a tracking error signal for tracking control.

[0086] In the embodiment of the application, the measurement light in the double electro-optical frequency comb has a center frequency of F a =100MHz and a repetition frequency of 1MHz, the bandwidth of the photodetector is 200MHz, and the cutoff frequency of the filter and amplifier module is 150MHz. The wavelength of the single-frequency laser is 780.24nm, and the wavelength of the indicating light is 650nm.

[0087] The tracking control and signal processing module 17 includes an image processing module 1701, a tracking error signal preprocessing module 1702, an angle decoding module 1703, a tracking control module 1707, a motor driver 1708, a synchronization module 1709 and a signal processing module 1711, and the signal processing module 1711 includes an absolute distance measurement signal processing module 1704, an air refractive index calculation module 1705, a relative displacement measurement signal processing module 1706 and a distance fusion module 1710.

[0088] The input ends of the image processing module 1701, the tracking error signal preprocessing module 1702 and the angle decoding module 1703 are electrically connected with the vision module 7, the two-dimensional position detector 1318 and the azimuth angle measuring module 11 respectively, the input ends of the absolute distance measuring signal processing module 1704 and the relative displacement measuring signal processing module 1706 are electrically connected with the first photoelectric detector 1317 and the second photoelectric detector 1318, the input end of the air refractive index calculation module 1705 is electrically connected with the environment monitoring sensor 2, and the output end of the air refractive index calculation module 1705 is also connected to the absolute distance measuring signal processing module 1704 and the relative displacement measuring signal processing module 1706 respectively; the absolute distance measuring signal processing module 1704 and the relative displacement measuring signal processing module 1706 both have three input ends, which are the first photoelectric detector 1317, the second photoelectric detector 1318 and the air refractive index calculation module 1705.

[0089] The output ends of the absolute distance measuring signal processing module 1704 and the relative displacement measuring signal processing module 1706 are connected to the distance fusion module 1710, the output ends of the image processing module 1701, the tracking error signal preprocessing module 1702, the angle decoding module 1703 and the distance fusion module 1710 are all connected to the tracking control module 1707 at the same time, and the output end of the tracking control module 1707 is connected to the azimuth torque motor 10 and the pitch torque motor 5 through the motor driver 1708.

[0090] The output ends of the angle decoding module 1703 and the distance fusion module 1710 are both connected to the synchronization module 1709, and the output end of the synchronization module 1709 is connected to the computer 18.

[0091] Figure 3 The tracking control and signal processing principle block diagram is shown, which is a further description of the working principle of the tracking control and signal processing module 17 in the Figure 1 .

[0092] The image processing module 1701 processes the image output by the vision module 7, adopts an artificial intelligence algorithm to quickly identify all target mirrors in the picture, and sorts and numbers them. The tracking error signal preprocessing module 1702 filters and amplifies the tracking error signal output by the two-dimensional position detector 1318. The angle decoding module 1703 decodes the angle measuring signals output by the pitch angle measuring module 8 and the azimuth angle measuring module 11, and calculates the angle value in real time.

[0093] In the absolute distance measurement mode, the first photodetector 1317 and the second photodetector 1318 together output a pair of multi-heterodyne interference signals; in the relative distance measurement mode, the first photodetector 1317 and the second photodetector 1318 together output a pair of heterodyne interference signals. The signals of the two modes are processed by the absolute distance signal processing module 1704 and the relative displacement signal processing module 1706 respectively, and the absolute distance and the relative displacement are obtained respectively. The air refractive index calculation module 1705 receives the air temperature, humidity and pressure parameters measured by the environmental monitoring sensor 2, calculates the air refractive index, and transmits it to the absolute distance signal processing module 1704 and the relative displacement signal processing module 1706 for air refractive index compensation.

[0094] The measurement results of the absolute distance signal processing module 1704 and the relative displacement signal processing module 1706 are transmitted to the distance fusion module 1710 for absolute distance zero point compensation of the rotation center of the rotating mirror 4, absolute distance and real-time displacement fusion calculation, and finally the real-time distance value of the target mirror is obtained.

[0095] The tracking control module 1707 combines the target mirror recognition result output by the image processing module 1701 and the angle information output by the angle decoding module 1703 to preliminarily judge the approximate position of the target mirror and guide the measurement light to irradiate the target mirror. After the measurement light irradiates the target mirror, the position deviation between the measurement light spot and the center of the target mirror can be detected by the two-dimensional position detector 1319 and processed by the tracking error signal preprocessing module 1702. The tracking control module 1707 uses a PID (Proportion-Integral-Differential) closed-loop control algorithm to calculate the tracking error signal output by the tracking error signal preprocessing module 1702 to obtain a feedback control signal, which is transmitted to the azimuth torque motor 10 and the elevation torque motor 5 through the motor driver 1708, to control the rotation of the rotating mirror 4, so that the measurement light irradiates the center of the target mirror, realizing closed-loop tracking of the target mirror. When the target mirror moves, the measurement light will automatically follow, ensuring that the measurement light always irradiates the center of the target mirror. The parameters of the PID closed-loop control algorithm are automatically adjusted according to the angle information output by the angle decoding module 1703 and the distance information output by the distance fusion module 1710.

[0096] The synchronization module 1709 obtains the elevation angle and azimuth angle information from the angle decoding module 1703 and the distance information from the distance fusion module 1710, respectively buffers the signals, takes the signal with the maximum delay as the reference, and controls the delay of the other two signals (takes the corresponding delay data in the buffer data), so that the signals after delay control are synchronized in time with the signal with the maximum delay. The synchronized signals are packaged and sent to the computer for conversion of three-dimensional space coordinates and display.

[0097] In summary, the application adopts a single ranging unit based on a double electro-optical frequency comb to realize the absolute ADM and RDM ranging functions and simultaneously realize the laser tracking error detection function, which can simplify the system structure, reduce the cost and avoid the measurement error introduced by the beam bifurcation; the visual module adopts a gear linkage mode for field control, which can ensure that the target mirror is always in the middle region of the field of view, which is conducive to multi-mirror identification and tracking control; the frame type body design is adopted to integrate the related modules, which is conducive to assembly and debugging, and the coaxial conductive ring is adopted to transmit signals, which can avoid the cable winding problem during rotation, and can rotate unlimitedly, and can be widely applied to the field of laser tracking interferometry.

[0098] The above specific embodiments are used to explain and illustrate the present application, rather than limit the present application, and any modifications and changes made to the present application within the spirit and protection scope of the claims fall within the protection scope of the present application.

Claims

1. A laser tracking interferometric spatial coordinate measurement system based on dual electro-optic frequency combs, characterized in that: It is divided into three parts: a precision optical tracking unit, a ranging unit based on a dual electro-optic frequency comb, and an electronic control unit. One part of the precision optical tracking unit is installed on the frame body (3), and the other part is installed on the object to be measured or the space to be measured. The ranging unit is installed inside the frame body (3). The electronic control unit is electrically connected to the precision optical tracking unit and the ranging unit respectively. The electronic control unit controls the ranging unit based on the dual electro-optic frequency comb to emit a beam of light from the dual electro-optic frequency comb, which is reflected and adjusted by the precision optical tracking unit and incident on the object to be measured or the space to be measured, and then received to measure the spatial coordinates of the object to be measured or the space to be measured. The precision optical tracking unit mainly includes a target mirror group (1), a rotating mirror (4), a pitch torque motor (5), a vision module (7), a pitch angle measurement module (8), an azimuth torque motor (10), and an azimuth angle measurement module (11). The target mirror group (1) is arranged on the object to be measured or in the space to be measured. The azimuth torque motor (10) is installed on the upper end of the frame body (3). A horizontal and parallel rotating mirror axis and vision axis are installed on the rotating end of the azimuth torque motor (10) through a bracket. At the same time, the rotating end of the azimuth torque motor (10) is provided with an azimuth angle measurement module (11) for detecting the rotation angle. One end of the rotating mirror axis is coaxially and fixedly connected to the rotating end of the pitch torque motor (5). The other end of the rotating mirror axis is connected to the pitch angle measurement module (8) for measuring the rotation angle of the rotating mirror axis. A rotating mirror (4) is fixedly installed on the rotating mirror. The vision axis is rotatably installed on the bracket through a gear set (6). A vision module (7) is fixedly installed on the vision axis. The ranging unit based on dual electro-optic frequency comb includes a beam adjustment module (12), a laser tracking interferometric ranging module (13), a light source modulation module (14), and a light source module (15) arranged sequentially from bottom to top. The light source module (15) outputs a single-frequency laser that traces back to the gas absorption peak. The single-frequency laser is transmitted to the light source modulation module (14) through a polarization-maintaining fiber and then electro-optic phase modulation to generate a dual electro-optic frequency comb. The dual electro-optic frequency comb is transmitted to the laser tracking interferometric ranging module (13). The laser tracking interferometric ranging module (13) outputs measurement light and transmits it to the beam adjustment module (12). The beam adjustment module (12) expands and collimates the measurement light and then adjusts it through translation and deflection control so that the measurement light is incident on the center of the rotating mirror (4). After being reflected by the rotating mirror (4), it is incident on the target mirror group (1) of the object to be measured or the space to be measured. After being reflected by the target mirror group (1), it returns to the laser tracking interferometric ranging module (13). The modulation of the control light source modulation module (14) is turned on and off, and then the absolute distance and relative displacement are measured by the laser tracking interferometric ranging module (13) in absolute ranging mode and relative displacement mode, respectively.

2. The laser tracking interferometric spatial coordinate measurement system based on dual electro-optic frequency combs according to claim 1, characterized in that: The pitch torque motor (5), vision module (7), pitch angle measurement module (8), azimuth torque motor (10) and azimuth angle measurement module (11) in the precision optical tracking unit are electrically connected through wires and a coaxial conductive ring (9) set at the upper end of the frame body (3).

3. The laser tracking interferometric spatial coordinate measurement system based on dual electro-optic frequency combs according to claim 1, characterized in that: The electronic control unit mainly includes a power supply module (16), a tracking control and signal processing module (17) and a computer (18). The tracking control and signal processing module (17) and the computer (18) are electrically connected. The power supply module (16) and the tracking control and signal processing module (17) are connected for power supply. The tracking control and signal processing module (17) is electrically connected to the precision optical tracking unit and the ranging unit, respectively. It also includes an environmental monitoring sensor (2), which is electrically connected to the tracking control and signal processing module (17) of the electronic control unit. The environmental monitoring sensor (2) is used to measure the temperature, humidity and air pressure parameters of the air and transmit them wirelessly to the tracking control and signal processing module (17).

4. The laser tracking interferometric spatial coordinate measurement system based on dual electro-optic frequency combs according to claim 1, characterized in that: The tracking control and signal processing module (17) of the electronic control unit processes and outputs a closed-loop control signal based on the target mirror information in the image obtained by the vision module (7) and the tracking error signal obtained by the laser tracking interferometric ranging module (13), thereby controlling the azimuth torque motor (10) and the pitch torque motor (5) to rotate the rotating mirror (4) to track the target mirror (101); at the same time, the azimuth angle measurement module (11) and the pitch angle measurement module (8) obtain the pitch angle and azimuth angle information of the target mirror in real time under the tracking state, and combine the distance information obtained by the laser tracking interferometric ranging module (13) to synchronously match the angle information and distance information, and obtain the three-dimensional coordinates of each target mirror (101) in the target target mirror group (1) after processing by the computer (18).

5. The laser tracking interferometric spatial coordinate measurement system based on dual electro-optic frequency combs according to claim 1, characterized in that: The laser tracking interferometric ranging module (13) includes a laser diode (1303), a fiber polarization-maintaining combiner (1304), a first collimator (1305), a first polarization beam splitter (1306), a reference corner cube prism (1307), a filter (1308), a first quarter-wave plate (1309), a second quarter-wave plate (1310), a second collimator (1314), a dichroic filter (1315), a second polarization beam splitter (1316), a first photodetector (1317), a second photodetector (1318), a two-dimensional position detector (1319), and a right-angle reflector (1320) installed in a shielded housing (1321). The measuring light emitted by the ranging unit from the dual electro-optic frequency comb and the indicating light emitted by the laser diode (1303) are incident together on the polarization-maintaining fiber combiner (1304) to form a first combined beam. After being expanded and collimated by the first collimator (1305), the beam is incident on the first polarizing beam splitter (1306) and undergoes the first transmission and reflection. The first combined beam after the first reflection of the first polarizing beam splitter (1306) is reflected by the first quarter-wave plate (1309), the filter (1308) and the reference corner prism (1307) in sequence, and then returns to the first polarizing beam splitter (1306) in reverse path and undergoes the second transmission. The first combined beam after the first transmission of the first polarizing beam splitter (1306) is reflected by the second quarter-wave plate (1310) and the right-angle mirror (1320) in sequence, and then exits through the window (1311) on the shielding shell (1321) to the beam adjustment module (12). After being adjusted by the beam adjustment module (12), the beam is incident on the target mirror group (1). After being reflected by the target mirror group (1), the beam returns to the first polarizing beam splitter (1306) in reverse path and undergoes the second reflection. The beams reflected and transmitted a second time after being reversed back to the first polarizing beam splitter (1306) are combined to form a second combined beam. This second combined beam is then incident on the dichroic filter (1315), where it is transmitted and reflected. The beam reflected by the dichroic filter (1315) is incident on the two-dimensional position detector (1319) and received to obtain the tracking error signal. The beam transmitted by the dichroic filter (1315) is then incident on the second polarizing beam splitter (1316), where it is reflected and transmitted respectively. The reference light emitted by the ranging unit from the dual electro-optic frequency comb passes through the second collimator (1314). After beam expansion and collimation, the light is incident on the second polarizing beam splitter (1316) and undergoes reflection and transmission. The beam of reference light reflected by the second polarizing beam splitter (1316) and the beam of the second combined beam transmitted by the second polarizing beam splitter (1316) are together incident on the first photodetector (1317) and received to obtain the reference interference signal. The beam of reference light transmitted by the second polarizing beam splitter (1316) and the beam of the second combined beam reflected by the second polarizing beam splitter (1316) are together incident on the second photodetector (1318) and received to obtain the measurement interference signal.

6. The laser tracking interferometric spatial coordinate measurement system based on dual electro-optic frequency combs according to claim 3, characterized in that: The tracking control and signal processing module (17) includes an image processing module (1701), a tracking error signal preprocessing module (1702), an angle decoding module (1703), a tracking control module (1707), a motor driver (1708), a synchronization module (1709), and a signal processing module (1711). The signal processing module (1711) includes an absolute distance measurement signal processing module (1704), an air refractive index calculation module (1705), a relative displacement measurement signal processing module (1706), and a distance fusion module (1710). The input terminals of the image processing module (1701), the tracking error signal preprocessing module (1702), and the angle decoding module (1703) are electrically connected to the vision module (7), the two-dimensional position detector (1319), and the azimuth measurement module (11), respectively. The input terminals of the absolute distance measurement signal processing module (1704) and the relative displacement measurement signal processing module (1706) are electrically connected to the first photodetector (1317) and the second photodetector (1318), respectively. The input terminal of the air refractive index calculation module (1705) is electrically connected to the environmental monitoring sensor (2). The output terminal of the air refractive index calculation module (1705) is also connected to the absolute distance measurement signal processing module (1704) and the relative displacement measurement signal processing module (1706), respectively. The outputs of the absolute distance measurement signal processing module (1704) and the relative displacement measurement signal processing module (1706) are connected to the distance fusion module (1710). The outputs of the image processing module (1701), the tracking error signal preprocessing module (1702), the angle decoding module (1703), and the distance fusion module (1710) are all connected to the tracking control module (1707). The output of the tracking control module (1707) is connected to the azimuth torque motor (10) and the pitch torque motor (5) via the motor driver (1708). The outputs of the angle decoding module (1703) and the distance fusion module (1710) are both connected to the synchronization module (1709), and the output of the synchronization module (1709) is connected to the computer (18).

7. A laser tracking interferometric spatial coordinate measurement and control method based on a dual electro-optic frequency comb for use in the laser tracking interferometric spatial coordinate measurement system of claim 1, characterized in that: 1) The light source module (15) outputs a single-frequency laser that traces back to the gas absorption peak. The single-frequency laser is transmitted to the light source modulation module (14) through the polarization-maintaining fiber and then generated by electro-optic phase modulation to produce a dual electro-optic frequency comb. The dual electro-optic frequency comb is transmitted to the laser tracking interferometric ranging module (13). The laser tracking interferometric ranging module (13) outputs the measurement light and transmits it to the beam adjustment module (12). The beam adjustment module (12) expands and collimates the measurement light and then adjusts it by translation and deflection control so that the measurement light is incident on the center of the rotating mirror (4). After being reflected by the rotating mirror (4), it is incident on the target mirror group (1) of the object to be measured or the space to be measured. After being reflected by the target mirror group (1), it returns to the laser tracking interferometric ranging module (13) to receive and obtain the tracking error signal, reference interference signal and measurement interference signal in real time. 2) The modulation of the light source modulation module (14) is controlled to turn on and off, and then the absolute distance and relative displacement are measured by the laser tracking interferometric ranging module (13) in absolute ranging mode and relative displacement mode respectively; At the same time, the air parameter signal is measured by the environmental monitoring sensor (2), and the pitch angle measurement module (8) and azimuth angle measurement module (11) are used to obtain the pitch angle and azimuth angle measurement signals of the rotating mirror (4) in real time. The image of the target mirror group (1) is also obtained in real time through the vision module (7). 3) The obtained tracking error signal, reference interference signal, measurement interference signal, air parameter signal, angle measurement signal, screen image, absolute distance and relative displacement are all input into the tracking control and signal processing module (17) for processing, controlling the rotation control of the pitch torque motor (5) and azimuth torque motor (10) and thus controlling the rotation of the rotating mirror (4) to realize closed-loop tracking of the target mirror group (1), and at the same time converting the synchronized angle information and distance information into three-dimensional spatial coordinates for display.

8. The laser tracking interferometric spatial coordinate measurement and control method based on dual electro-optic frequency combs according to claim 7, characterized in that: Step 3) is performed in the tracking control and signal processing module (17). The air parameter signal, reference interference signal, measurement interference signal, and angle measurement signal are transmitted to the tracking control and signal processing module (17) for processing. The angle measurement signal is transmitted to the angle decoding module (1703) for decoding to obtain angle information. The reference interference signal and measurement interference signal are transmitted to the signal processing module (1711) for processing and compensation using the air parameter signal to obtain distance information. The tracking error signal is transmitted to the tracking error signal preprocessing module (1702) for processing to obtain the position deviation information between the measurement light spot and the center of the target mirror (101). The image is transmitted to the image processing module (1701) for processing to obtain the identification information of all target mirrors. On the one hand, the identification information, position deviation information, angle information and distance information of all target mirrors are transmitted to the tracking control module (1707), and the feedback control signal is obtained by the closed-loop control algorithm. The signal is then transmitted to the pitch torque motor (5) and azimuth torque motor (10) via the motor driver (1708) to control the rotation of the rotating mirror and realize closed-loop tracking of the target mirror. On the other hand, the synchronization module (1709) performs synchronization processing to eliminate the delay between angle information and distance information, and then transmits the synchronized angle information and distance information to the computer (18) for the conversion and display of three-dimensional spatial coordinates.

Images