Dual electro-optic frequency comb-based laser tracking interferometric spatial coordinate measurement system and method

Abstract

Disclosed in the present invention are a dual electro-optic frequency comb-based laser tracking interferometric spatial coordinate measurement system and method. Multiple target mirrors are identified by means of a vision module, to guide a rotating mirror to direct laser light toward each target mirror individually. A laser tracking interferometric ranging module obtains a tracking error of the laser beam deviating from the center of the target mirror to be used for closed-loop tracking control. A light source module outputs single-frequency laser light traceable to a gas absorption peak. By controlling a light source modulation module to enable or disable an electro-optic phase modulation drive signal, dual electro-optic frequency combs or dual-frequency continuous-wave laser light is outputted. In a tracking state, the laser tracking interferometric ranging module respectively uses the two light sources to measure the absolute distance and the relative displacement of a target mirror, and the real-time distance between the target mirror and an original point is computed by means of distance fusion; the elevation angle and the azimuth angle of the target mirror are obtained in real time by means of an azimuth angle and elevation angle measurement module; tracking control and coordinate computation are carried out by means of a tracking control and signal processing module and a computer, and finally three-dimensional spatial coordinates of all the target mirrors are measured.

Description

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

[0001] The present application belongs to the technical field of laser tracking measurement, in particular to a laser tracking interferometry spatial coordinate measurement system and method based on dual electro-optic frequency combs. BACKGROUND

[0002] Laser tracking interferometry measurement technology is widely used in large-size high-end equipment assembly, industrial robot positioning accuracy calibration and other fields due to its advantages of large measurement range, high precision and fast speed.

[0003] Distance measurement is the core technology of laser tracking interferometry measurement. The existing laser tracking interferometry measurement method usually combines absolute distance measurement (ADM) and relative displacement measurement (RDM) two ranging methods for 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 ADM and RDM two 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 interferometry measurement. SUMMARY

[0005] In order to solve the problems in the background art, the present application discloses a laser tracking interferometry spatial coordinate measurement system and method based on dual electro-optic frequency combs, which uses a single ranging module based on dual electro-optic frequency combs to realize ADM and RDM two ranging functions.

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

[0007] I. A laser tracking interferometry spatial coordinate measurement system based on dual electro-optic frequency combs:

[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 a 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 single-frequency laser traced to the gas absorption peak, the single-frequency laser is transmitted to the light source modulation module through the polarization maintaining optical fiber to generate a double electro-optic frequency comb after electro-optic phase modulation, the double electro-optic frequency comb is transmitted to the laser tracking interference distance measurement module, the laser tracking interference distance measurement module outputs the measurement light to the beam adjustment module, the measurement light is expanded and collimated by the beam adjustment module, and then the translation and deflection control adjustment is performed, so that the measurement light is incident to the center of the rotating mirror in parallel to the direction of gravity, is reflected by the rotating mirror, and is incident to the target mirror of the target mirror group of the object to be measured or the space to be measured, and is reflected by the target mirror of the target mirror group to return to the laser tracking interference distance measurement module to obtain tracking error signals, reference interference signals and measurement interference signals in real time, and then be used to realize distance measurement and tracking error acquisition.

[0024] One of the double electro-optic frequency combs is used as the measurement light, and the other of the double electro-optic frequency combs is used as the reference light after frequency shift by acousto-optic modulation, and the reference light and the measurement light are commonly transmitted to the laser tracking interference distance measurement module through the polarization maintaining optical fiber.

[0025] Then in the laser tracking interference distance measurement module, the measurement light is combined with the indication light output by the laser diode through the polarization maintaining optical fiber combiner; the measurement light and the reference light are expanded and collimated by the first collimator and the second collimator respectively. The measurement light and the reference light are both divided into p-polarization state components and s-polarization state components.

[0026] The p-polarization state component in the measurement light is transmitted through the first polarization beam splitter, output to the beam adjustment module through the second quarter-wave plate, the right-angle reflector and the window piece, and returned after reflection by the rotating mirror and the target mirror; the s-polarization state component in the measurement light is reflected by the first polarization beam splitter, reflected by the first quarter-wave plate, the filter and the reference corner cube after reflection by the reference corner cube, and returned; the two returned measurement lights are first processed by the dichroic piece to be transmitted and reflected, the indication light reflected by the dichroic piece is transmitted to the two-dimensional position detector to obtain the tracking error signal used for tracking control, the measurement light transmitted by the dichroic piece is reflected and transmitted at the second polarization beam splitter respectively; the s-polarization state component of the reference light is reflected by the second polarization beam splitter, and then transmitted to the first photodetector together with the p-polarization state component of the measurement light transmitted by the dichroic piece to obtain the reference interference signal; the p-polarization state component of the reference light is transmitted by the second polarization beam splitter, and then transmitted to the second photodetector together with the s-polarization state component of the measurement light reflected by the dichroic piece to obtain the measurement interference signal, and the reference interference signal and the measurement interference signal are used for distance measurement.

[0027] 2) The modulation of turning on and off of the light source modulation module is controlled, and then the absolute distance and the relative displacement are measured and obtained in the absolute distance measurement mode and the relative displacement mode respectively by the laser tracking interference distance measurement module;

[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 input into the tracking control and signal processing module for processing, the rotation 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 of:

[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 control, which can ensure that the target mirror is always in the middle area of the field of view, and is conducive to multi-mirror identification and tracking control.

[0045] (3) The present application adopts a frame 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 ranging principle block diagram of a laser tracking interference based on a double electro-optical frequency comb.

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

[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, 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 Figure 1, the laser tracking interference space coordinate measurement system based on double electro-optical frequency comb specifically comprises:

[0054] The whole device is divided into three parts: a precision optical tracking unit, a distance measuring unit based on double electro-optical frequency comb, and an electric 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 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 precision optical tracking unit and the distance measuring unit respectively. The electric control unit controls the distance measuring unit based on double electro-optical frequency comb to emit a double electro-optical frequency comb light beam, which is reflected and adjusted by the precision 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.

[0055] The precision optical tracking unit mainly comprises 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.

[0056] The target mirror group 1 comprises 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.

[0057] 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.

[0058] The rotating mirror shaft is 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.

[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.

[0062] The ranging unit based on the double electro-optical frequency comb mainly comprises, from bottom to top, 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 which are coaxially arranged in sequence and 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 output by the light source module 15 is transmitted to the light source modulation module 14 through a polarization maintaining optical fiber for electro-optical phase modulation to generate the double electro-optical frequency comb.

[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 light 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 then 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 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 measuring 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 combined with the rotation of the turning mirror 4.

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

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

[0073] The laser tracking interferometric distance measuring 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 distance measuring unit emits measurement light in the double electro-optical frequency comb, which is incident together with the indicating light emitted by the laser diode 1303 into the polarization-maintaining fiber combiner 1304 to form first combined light. The first combined light is expanded and collimated by the first collimator 1305 and then incident into 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 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 through the window piece 1311 on the shielding shell 1321 to the beam adjustment module 12. After adjustment by the beam adjustment module 12, the first combined light is incident into the target mirror 101 in the target mirror group 1 and then returns to the first polarization beam splitter 1306 to undergo second reflection after reflection by the target mirror 101 in the target mirror group 1.

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

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

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

[0078] In specific implementation, the two-dimensional position detector 1319, the first photodetector 1317, and the second photodetector 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. 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 interference distance measuring 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 expanded and collimated by the first collimator 1305 and the second collimator 1314, respectively. The measurement light and the reference light are both divided into p-polarization state components and s-polarization state components.

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

[0081] Wherein, the first photodetector 1317 and the second photodetector 1318 are internally integrated with polarizing plates, and the transmission axis of the polarizing plate is 45° different from the p-polarization state of the second polarizing beam splitter 1316.

[0082] The laser tracking interference distance measuring module 13 has two functions of absolute distance measurement and relative displacement measurement, 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 to output a double electro-optical frequency comb, at this time, the first photodetector 1317 and the second photodetector 1318 of the laser tracking interference distance measuring module 13 respectively obtain a reference multi-heterodyne interference signal and a measuring multi-heterodyne interference signal, and after signal processing, an 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 to 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 interference distance measuring module 13 respectively obtain a reference heterodyne interference signal and a measuring heterodyne interference signal, and after signal processing, a 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 present application, the center frequency of the measuring light in the dual electro-optical frequency comb is higher than that of the reference light by F a =100MHz, the repetition frequency is higher than that of the reference light by 1MHz; the bandwidth of the photoelectric detector is 200MHz, and the cutoff frequency of the filter amplification 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 comprises 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, wherein the signal processing module 1711 comprises 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 to the vision module 7, the two-dimensional position detector 1318, and the azimuth angle measurement module 11 respectively, the input ends of the absolute distance measurement signal processing module 1704 and the relative displacement measurement signal processing module 1706 are electrically connected to 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 to the environment monitoring sensor 2, and the output end 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 absolute distance measurement signal processing module 1704 and the relative displacement measurement 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 measurement signal processing module 1704 and the relative displacement measurement 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] Fig. 3 is a schematic diagram of the tracking control and signal processing principle, which is a further illustration of the working principle of the tracking control and signal processing module 17 in Fig. 1.

[0092] The image processing module 1701 processes the image output by the vision module 7, uses artificial intelligence algorithm to quickly identify all the targets 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 measurement signals output by the pitch angle measurement module 8 and the azimuth angle measurement module 11, and calculates the angle value in real time.

[0093] In the ADM absolute ranging mode, the first photodetector 1317 and the second photodetector 1318 together output a pair of multi-heterodyne interference signals; in the RDM relative ranging 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 ranging 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 through wireless transmission, calculates the air refractive index, and transmits it to the absolute ranging signal processing module 1704 and the relative displacement signal processing module 1706 for air refractive index compensation.

[0094] The measurement results of the absolute ranging 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 turning 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 scope recognition result output by the image processing module 1701 and the angle information output by the angle decoding module 1703 to preliminarily determine the approximate position of the target scope and guide the measurement light to irradiate the target scope. After the measurement light irradiates the target scope, the position deviation between the measurement light spot and the center of the target scope 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 scope, realizing closed-loop tracking of the target scope. When the target scope moves, the measurement light will automatically follow, ensuring that the measurement light always irradiates the center of the target scope. 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 data corresponding to the delay in the buffered 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 present application uses a single ranging unit based on a double electro-optical frequency comb to realize both absolute ADM and RDM ranging functions and simultaneously realize laser tracking error detection function, which can simplify the system structure, reduce the cost and avoid the measurement error introduced by beam bifurcation; the visual module uses a gear linkage method to control the field of view, which can ensure that the target scope is always in the middle region of the field of view, which is conducive to multi-target scope recognition and tracking control; the frame type body design integrates related modules, which is conducive to assembly and debugging, and the coaxial conductive ring is used to transmit signals, which can avoid cable winding problem during rotation and can rotate unlimitedly, which can be widely used in 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, 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 double electro-optical frequency comb, characterized in that: It is divided into three parts of precision optical tracking unit, double electro-optical frequency comb based ranging unit and electric control unit; one part of the precision optical tracking unit is installed on the frame body (3), the other part is installed on the measured object or space, the ranging unit is installed in the frame body (3), the electric control unit is electrically connected with the precision optical tracking unit and the ranging unit respectively, the electric control unit controls the double electro-optical frequency comb based ranging unit to emit the light beam of double electro-optical frequency comb, which is reflected and adjusted by the precision optical tracking unit to be incident on the measured object or space, and then receives the spatial coordinate measurement of the measured object or space.

2. A laser tracking interferometry spatial coordinate measurement system based on dual electro-optical frequency combs according to claim 1, characterized in that: The precision optical tracking unit mainly comprises 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 measured object or in the measured space; the azimuth torque motor (10) is installed on the upper end of the frame body (3), a horizontal and parallel rotating mirror shaft and a vision shaft are installed on the rotating end of the azimuth torque motor (10) through a support, and 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 shaft is coaxially fixedly connected with the rotating end of the pitch torque motor (5), 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, and the rotating mirror is fixedly installed with the rotating mirror (4); the vision shaft is rotatably installed on the support through a gear set (6), and the vision module (7) is fixedly installed on the vision shaft.

3. A laser tracking interferometry spatial coordinate measurement system based on dual electro-optical frequency combs according to claim 1, characterized in that: The double electro-optical frequency comb based ranging unit comprises, from bottom to top, a light beam adjusting module (12), a laser tracking interferometric ranging module (13), a light source modulation module (14) and a light source module (15); The light source module (15) outputs single-frequency laser traced to gas absorption peak, the single-frequency laser is transmitted to the light source modulation module (14) through a polarization maintaining optical fiber to generate double electro-optical frequency comb after electro-optical phase modulation, the double electro-optical frequency comb is transmitted to the laser tracking interferometric ranging module (13), the laser tracking interferometric ranging module (13) outputs measurement light to the light beam adjusting module (12), the measurement light is expanded and collimated by the light beam adjusting module (12), and then is adjusted by translation and deflection control, so that the measurement light is incident on the center of the rotating mirror (4), is reflected by the rotating mirror (4) and is incident on the target mirror group (1) of the measured object or space, and is returned to the laser tracking interferometric ranging module (13) after being reflected by the target mirror group (1).

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

5. A laser tracking interferometry spatial coordinate measurement system based on dual electro-optical frequency combs according to claim 1, characterized in that: The electric control unit mainly comprises 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 precise optical tracking unit and the distance measuring unit respectively; The environment monitoring sensor (2) is electrically connected with the tracking control and signal processing module (17) of the electric control unit, and the environment monitoring sensor (2) is used for measuring the temperature, humidity and air pressure parameters of air and transmitting the parameters to the tracking control and signal processing module (17) through wireless transmission.

6. A laser tracking interferometry spatial coordinate measurement system based on dual electro-optical frequency combs according to claim 1, characterized in that: The tracking control and signal processing module (17) of the electric control unit processes and outputs a closed-loop control signal according to the target mirror information in the image obtained by the visual module (7) and the tracking error signal obtained by the laser tracking interference distance measuring module (13), and then controls the rotation of the rotating mirror (4) of the azimuth torque motor (10) and the elevation torque motor (5) to track the target mirror (1); meanwhile, the azimuth angle measuring module (11) and the elevation angle measuring module (8) are used to obtain the angle information of the azimuth angle and the elevation angle of the target mirror in the tracking state, the distance information obtained by the laser tracking interference distance measuring module (13) is combined, the angle information and the distance information are matched synchronously, and the three-dimensional coordinates of each target mirror (101) in the target mirror group (1) are obtained after the computer (18) processes.

7. A dual electro-optical frequency comb based laser tracking interferometry spatial coordinate measuring system according to claim 1, characterized in that: The laser tracking interferometric distance measuring module (13) comprises 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) installed in a shielded housing (1321); the measuring light in the double 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 first combined light, and the first combined light is expanded and collimated by the first collimator (1305) and then incident on 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) 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 shielded housing (1321) through the window sheet (1311) to the beam adjusting module (12), and after being adjusted by the beam adjusting module (12), the light is incident on the target mirror group (1) and then returns to the first polarization beam splitter (1306) to undergo second reflection. The second combined light after the second reflection and the second transmission of the first polarization beam splitter (1306) is reflected by the dichroic filter (1316) to undergo transmission and reflection, the light reflected by the dichroic filter (1316) is received by the two-dimensional position detector (1319) to obtain a tracking error signal, and the light transmitted by the dichroic filter (1316) is reflected and transmitted by the second polarization beam splitter (1316) respectively; the reference light in the double electro-optic frequency comb is expanded and collimated by the second collimator (1314) and then incident on the second polarization beam splitter (1316) to undergo reflection and transmission, the light reflected by the second polarization beam splitter (1316) and the light transmitted by the second polarization beam splitter (1316) are received by the first photodetector (1317) to obtain a reference interference signal, and the light transmitted by the second polarization beam splitter (1316) and the light reflected by the second polarization beam splitter (1316) are received by the second photodetector (1318) to obtain a measurement interference signal.

8. The laser tracking interferometry spatial coordinate measurement system based on dual electro-optical frequency combs according to claim 1, characterized in that: the tracking control and signal processing module (17) comprises 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) comprises 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 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 measurement module (11) respectively, the input ends of the absolute distance measurement signal processing module (1704) and the relative displacement measurement 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 measurement signal processing module (1704) and the relative displacement measurement signal processing module (1706) respectively; the output ends 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), and 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); the output ends of the angle decoding module (1703) and the distance fusion module (1710) are connected to the synchronization module (1709), and the output end of the synchronization module (1709) is connected to the computer (18).

9. A laser tracking interferometry spatial coordinate measurement and control method based on dual electro-optical frequency combs for the laser tracking interferometry spatial coordinate measurement system according to claim 1, characterized in that: 1) The light source module (15) outputs single-frequency laser traced to the gas absorption peak, the single-frequency laser is transmitted to the light source modulation module (14) through the polarization maintaining optical fiber, and the double electro-optic frequency comb is generated after the electro-optic phase modulation, the double electro-optic frequency comb is transmitted to the laser tracking interference distance measurement module (13), the laser tracking interference distance measurement module (13) outputs the measurement light to the light beam adjustment module (12), the measurement light is expanded and collimated by the light beam adjustment module (12), then the translation and deflection control adjustment are performed, so that the measurement light is incident to the center of the rotating mirror (4), is reflected by the rotating mirror (4), and is incident to the target mirror group (1) of the object to be measured or the space to be measured, and the tracking error signal, the reference interference signal and the measurement interference signal are obtained by the laser tracking interference distance measurement module (13) receiving in real time after the target mirror group (1) is reflected and returns; 2) The modulation of the opening and closing of the light source modulation module (14) is controlled, and then the absolute distance and the relative displacement are measured and obtained in the absolute distance measurement mode and the relative displacement mode respectively through the laser tracking interference distance measurement module (13); At the same time, the air parameter signal is measured by the environment monitoring sensor (2), the angle measurement signals of the pitch angle and the azimuth angle of the rotating mirror (4) are obtained in real time through the pitch angle measurement module (8) and the azimuth angle measurement module (11), and the picture image of the target mirror group (1) is obtained in real time through the vision module (7); 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 input into the tracking control and signal processing module (17) for processing, the rotation control of the pitch torque motor (5) and the azimuth torque motor (10) is controlled, and then the rotation of the rotating mirror (4) is controlled, the closed-loop tracking of the target mirror group (1) is realized, and the synchronous angle information and distance information are converted into three-dimensional space coordinates for display.

10. A laser tracking interferometry spatial coordinate measurement and control method based on dual electro-optical frequency combs according to claim 9, characterized in that: In the tracking control and signal processing module (17), 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 (17) for processing, wherein the angle measurement signal is transmitted to the angle decoding module (1703) for decoding to obtain angle information, the reference interference signal and the measurement interference signal are transmitted to the signal processing module (1711) for processing and compensation to obtain distance information, the tracking error signal is transmitted to the tracking error signal preprocessing module (1702) for processing to obtain position deviation information of the measurement light spot and the target mirror (4), and the picture image is transmitted to the image processing module (1701) for processing to obtain identification information of all target mirrors; 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 (1707), the feedback control signal is obtained through the closed-loop control algorithm, the motor driver (1708) is transmitted to the pitch torque motor (5) and the azimuth torque motor (10), the rotation of the rotating mirror is controlled, and the closed-loop tracking of the target mirror is realized. On the other hand, the synchronization module (1709) is used 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 the computer (18) for conversion and display of the three-dimensional space coordinates.

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