Single-station multi-target spatial coordinate measurement method based on photoelectric scanning and absolute ranging

Abstract

The application discloses a kind of single station multi-target space coordinate measurement methods based on photoelectric scanning and absolute ranging, comprising: constructing integrated measurement base station and cooperative target, the relative position of photoelectric scanning module and absolute ranging module on measurement base station is calibrated, the position of photoelectric receiving unit and optical reflection unit on cooperative target is calibrated;The rotation angle and normal vector of scanning light plane are obtained, with the center position of optical reflection unit as target measurement point, the coarse measurement coordinates of target measurement point are calculated;Absolute ranging module is guided ranging light beam according to coarse measurement coordinates and is aligned with the center position of optical reflection unit, the distance between optical reflection unit and absolute ranging module is measured;Establish coordinate measurement model, and calculate the accurate space coordinates of target measurement point.The application realizes the automatic coordinate measurement of single station measurement equipment to space multi-target.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of large-scale space coordinate precision measurement in industrial field, and particularly relates to a single-station multi-target space coordinate measurement method based on photoelectric scanning and absolute ranging. BACKGROUND

[0002] Large-scale space coordinate precision measurement is a basic supporting technology for advanced manufacturing industries such as aviation, aerospace, shipbuilding and automobile manufacturing, and plays an important role in product part assembly, industrial robot positioning, final quality detection and other fields. The distributed measurement system represented by indoor GPS is based on the principle of spatial intersection, which can flexibly expand the range while ensuring high precision, realize multi-target parallel measurement, but has the problems of too many devices, complex global orientation operation, inconvenient movement after networking, and poor intersection conditions in complex environments.

[0003] The total station type devices such as laser tracker and laser radar can work independently and are convenient to replace the working space, but are limited by the tracking mechanism and angle measurement principle, and can only measure single point and need manual guidance or marking, so the measurement efficiency is low and the automation degree is low. SUMMARY

[0004] The present application provides a single-station multi-target space coordinate measurement method based on photoelectric scanning and absolute ranging, which realizes automatic coordinate measurement of space multi-target by single-station measurement device, as described in detail below:

[0005] A single-station multi-target space coordinate measurement method based on photoelectric scanning and absolute ranging, the method comprising:

[0006] An integrated measurement base station and a cooperative target are constructed, the relative positions of the photoelectric scanning module and the absolute ranging module on the measurement base station are calibrated, and the positions of the photoelectric receiving unit and the optical reflection unit on the cooperative target are calibrated;

[0007] The rotation angle and normal vector of the scanning light plane are obtained, the center position of the optical reflection unit is taken as the target measurement point, and the coarse measurement coordinates of the target measurement point are calculated;

[0008] The absolute ranging module guides the ranging light beam to aim at the center position of the optical reflection unit according to the coarse measurement coordinates, and measures the distance between the optical reflection unit and the absolute ranging module;

[0009] A coordinate measurement model is established, and the accurate space coordinates of the target measurement point are calculated.

[0010] The absolute ranging module comprises an absolute laser range finder, a light beam guiding mechanism and a light beam centering feedback control mechanism.

[0011] The absolute distance measuring module is located below the photoelectric scanning module, the absolute laser range finder adopts femtosecond laser ranging principle or frequency-modulated continuous wave ranging principle to realize absolute distance measurement, the beam guiding mechanism deflects the ranging beam emitted by the absolute laser range finder based on a fast mirror and switches between multiple target units, the beam centering feedback control mechanism obtains the offset of the returned beam through the mirror and the optical reflection unit through a four-quadrant photodetector, and adjusts the beam guiding mechanism through a control unit to form a beam adjustment closed-loop system, so that the ranging beam is aligned with the target measurement point.

[0012] The cooperation target is provided with a photoelectric receiving unit, an optical reflection unit and a signal processing unit.

[0013] The photoelectric receiving unit is fixed on the cooperation target in an equilateral triangle shape, used for receiving scanning light signals and synchronous light signals and converting them into logic pulses; the optical reflection unit is fixed on the cooperation target in the same plane as the three photoelectric receiving units, reflecting the ranging beam to return along the original path; and the signal processing unit is located inside the cooperation target, converting the output signals of the photoelectric receiving unit into the rotation angle of the scanning light plane.

[0014] The relative positions of the photoelectric scanning module and the absolute distance measuring module on the calibration measurement base station are as follows:

[0015] A high-precision control field is constructed by using a laser tracker, the photoelectric scanning module measures each control point, and the directional parameters of the tracker coordinate system and the photoelectric scanning module coordinate system are established according to the spatial resection principle;

[0016] The absolute distance measuring module measures the distance between each control point and the distance measuring module, the ranging origin coordinates are obtained by using the multi-lateration principle, as the origin of the absolute distance measuring coordinate system, the beam guiding mechanism rotates the two rotation axes respectively and keeps the deflection angle of the other rotation axis to be zero, rotates multiple times to different angles and measures the point coordinates on the light path of the ranging beam by using the laser tracker, and the two axes of the absolute distance measuring coordinate system are established by fitting the plane normal vector respectively, and the other axis is determined according to the right-hand coordinate system, so that the directional parameters of the tracker coordinate system and the absolute distance measuring module coordinate system are obtained;

[0017] The directional parameters of the photoelectric scanning module coordinate system and the absolute distance measuring module coordinate system are calculated by using the directional parameters between the photoelectric scanning module coordinate system, the absolute distance measuring module coordinate system and the tracker coordinate system.

[0018] The rotation angle and the normal vector of the scanning light plane are obtained, the center position of the optical reflection unit is taken as the target measurement point, and the coarse measurement coordinates of the target measurement point are calculated as follows:

[0019] The rotation angle of the two scanning light planes when passing each photoelectric receiving unit is acquired by the signal processing unit, the light plane normal vector of the corresponding position is obtained according to the rotation transformation, and six plane constraint conditions are established according to this, the distance between the photoelectric receiving unit and the optical reflection unit on the cooperative target also establishes six structure constraint conditions, and the spatial coordinates of the photoelectric receiving unit and the optical reflection unit are established to optimize the equation for iterative solution, so that the coarse measurement coordinates of the target measurement point in the photoelectric scanning module coordinate system are obtained.

[0020] The coordinate measurement model is established, and the spatial coordinates of the target measurement point are calculated as follows:

[0021] The distance between the target measurement point and the absolute distance measuring module is introduced as a constraint condition, combined with the plane constraint condition and the structure constraint condition, an optimization equation is established, and iterative optimization solution is performed again to obtain the spatial coordinates of the target measurement point.

[0022] The beneficial effects of the technical scheme provided by the application are:

[0023] 1. The application uses a single measurement base station in cooperation with a cooperative target to realize automatic measurement of multiple targets in a full range, performs coarse measurement of the spatial coordinates of multiple target points to be measured by an optical-electrical scanning method, completes accurate alignment of the ranging light beam to the optical reflection unit by using a light beam guiding mechanism, measures the high-precision absolute distance between the target point to be measured and the ranging origin by an absolute distance measuring module, and performs high-dynamic and fast switching between different targets to realize independent measurement of length observation and angle observation, thereby effectively improving the principle limitation of the simultaneous measurement of length and angle of the existing single-station measuring instrument.

[0024] 2. The application adopts optical-electrical scanning angle measurement and laser ranging to establish light plane constraints and distance constraints, constructs an optimization equation, and performs iterative solution to realize high-precision spatial coordinate measurement of the target point to be measured.

[0025] 3. The method improves the difficulties in layout and poor intersection conditions of the multi-node intersection measurement technology in some complex or relatively narrow working environments, effectively solves the efficiency problem of the single-point sequential measurement of the tracking instrument, total station and other single-station instruments and the need for manual guidance, and realizes high-efficiency and high-precision multi-target spatial coordinate measurement. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a work flow chart of the single-station multi-target spatial coordinate measurement method based on optical-electrical scanning and absolute ranging.

[0027] Figure 2 It is a structural schematic diagram of an integrated measurement base station.

[0028] Figure 3 It is a structural schematic diagram of an absolute ranging module.

[0029] Figure 4 Structure diagram of cooperative target.

[0030] In the drawings, the components represented by each reference numeral are listed as follows:

[0031] 1: base station housing; 2: absolute ranging module;

[0032] 3: rotor platform; 4: scanning laser;

[0033] 5: synchronous pulse laser; 6: photoelectric receiving unit;

[0034] 7: optical reflection unit; 8: signal processing unit. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present application clearer, the embodiments of the present application are described in further detail below.

[0036] Single-station multi-target spatial coordinate measurement method based on photoelectric scanning and absolute ranging, see Figures 1 to 4 The method comprises the following steps:

[0037] Step 101: constructing an integrated measurement base station and a cooperative target, calibrating the relative positions of the photoelectric scanning module and the absolute ranging module 2 on the measurement base station, and calibrating the positions of the photoelectric receiving unit 6 and the optical reflection unit 7 on the cooperative target (as shown in the figure); Figure 4

[0038] Step 102: obtaining the rotation angle and normal vector of the scanning light plane, taking the center position of the optical reflection unit 7 as the target measurement point, and calculating the coarse measurement coordinates of the target measurement point;

[0039] Step 103: the absolute ranging module 2 guides the ranging light beam to aim at the center position of the optical reflection unit 7 according to the coarse measurement coordinates, and measures the distance between the optical reflection unit 7 and the absolute ranging module 2;

[0040] Step 104: establishing a coordinate measurement model and calculating the accurate spatial coordinates of the target measurement point.

[0041] In step 101, the construction of the integrated measurement base station and the cooperative target specifically comprises:

[0042] The integrated measurement base station comprises: a base station housing 1, a photoelectric scanning module and an absolute ranging module 2.

[0043] ​The photoelectric scanning module comprises a rotor platform 3, a scanning laser 4 and a synchronous pulse laser 5; the scanning laser 4 is installed on the rotor platform 3 to realize full-circumferential space scanning, the synchronous pulse laser 5 is fixed in a ring on the base station shell 1, and the synchronous pulse laser 5 is triggered once when the rotor platform 3 is turned to zero position.

[0044] The absolute distance measuring module 2 comprises an absolute laser range finder, a light beam guiding mechanism and a light beam centering feedback control mechanism; the absolute distance measuring module 2 is located below the photoelectric scanning module, the absolute laser range finder realizes high-precision absolute distance measurement by using femtosecond laser ranging principle or frequency-modulated continuous wave ranging principle, the light beam guiding mechanism switches the ranging light beams emitted by the absolute laser range finder between multiple target units based on high-speed deflection of a fast mirror, and the light beam centering feedback control mechanism obtains the offset amount of the return light beams of the fast mirror and the optical reflection unit through a four-quadrant photodetector, adjusts the light beam guiding mechanism through a control unit, and forms a light beam adjustment closed-loop system to accurately align the ranging light beam with the target measurement point.

[0045] The cooperation target is provided with a photoelectric receiving unit 6, an optical reflection unit 7 and a signal processing unit 8.

[0046] Further, the photoelectric receiving unit 6 is fixed on the cooperation target in an equilateral triangle shape, is used for receiving scanning light signals and synchronous light signals and converting them into logic pulses; the optical reflection unit 7 is fixed on the cooperation target in a plane with the three photoelectric receiving units 6, reflects the ranging light beams to return along the original path; and the signal processing unit 8 is located inside the cooperation target, converts the output signals of the photoelectric receiving unit 6 into the rotation angle of the scanning light plane.

[0047] Further, the step 101 of calibrating the positions of the photoelectric scanning module and the absolute distance measuring module 2 on the measurement base station comprises the following steps:

[0048] Step 1-1: a high-precision control field is constructed by using a laser tracker, the photoelectric scanning module measures each control point, and directional parameters of the laser tracker coordinate system and the photoelectric scanning module coordinate system are established according to the space resection principle;

[0049] Step 1-2: the absolute distance measuring module 2 measures the distance between each control point and the distance measuring module, obtains the distance measuring origin coordinates by using the multi-lateration principle as the origin of the absolute distance measuring coordinate system, the light beam guiding mechanism rotates two rotation axes and keeps the deflection angle of the other rotation axis to be zero, rotates multiple times to different angles and measures the point coordinates on the light path of the ranging light beam by using the laser tracker, two axes of the absolute distance measuring coordinate system are respectively established by the fitting plane vector, and the other axis is determined according to the right-hand coordinate system, so that the directional parameters of the laser tracker coordinate system and the absolute distance measuring module coordinate system are obtained;

[0050] Step 1-3: The orientation parameters between the photoelectric scanning module coordinate system, the absolute distance measuring module coordinate system and the tracker coordinate system obtained in steps 1-1 and 1-2 are used to realize the orientation parameter calculation of the photoelectric scanning module coordinate system and the absolute distance measuring module coordinate system.

[0051] In step 101, the positions of the photoelectric receiving units 6 and the optical reflection units 7 on the cooperative target are calibrated, specifically, the distances between each two photoelectric receiving units 6 and the distances between the optical reflection units 7 and each photoelectric receiving unit 6 are calibrated by using a laser tracker or an image measuring instrument.

[0052] Further, in step 102, the rotation angles of the two scanning light planes passing through each photoelectric receiving unit 6 are obtained by the signal processing unit 8, the light plane normal vectors of the corresponding positions are obtained according to the rotation transformation, and accordingly, six plane constraint conditions are established. In addition, the distances between the photoelectric receiving units 6 and the optical reflection units 7 on the cooperative target also establish six structure constraint conditions. The optimization equation for the space coordinates of the photoelectric receiving units 6 and the optical reflection units 7 is established and iteratively solved to obtain the coarse measurement coordinates of the target measurement point in the photoelectric scanning module coordinate system.

[0053] Further, in step 103, the coarse measurement coordinates in the photoelectric scanning module coordinate system are converted to the absolute distance measuring module coordinate system, and the target measurement point is aligned according to the coordinate information to obtain the absolute distance between the target point and the absolute distance measuring module 2.

[0054] Further, in step 104, by introducing the distance between the target measurement point and the absolute distance measuring module as a constraint condition, combining the plane constraint condition and the structure constraint condition, an optimization equation is established, and iterative optimization is performed again to obtain the accurate space coordinates of the target measurement point.

[0055] Embodiment 1

[0056] The single-station multi-target space coordinate measurement method based on photoelectric scanning and absolute distance measurement, as shown in Figures 1 to 4 , comprises the following steps:

[0057] Step 201: As shown in Figure 2 , Figure 3 and Figure 4 , an integrated measurement base station and a cooperative target are constructed, the positions of the photoelectric scanning module and the absolute distance measuring module 2 on the measurement base station are calibrated, and the positions of the photoelectric receiving units 6 and the optical reflection units 7 on the cooperative target are calibrated.

[0058] Step 202: The rotation angle and the normal vector of the scanning light plane are obtained, the center position of the optical reflection unit 7 is taken as the target measurement point, and the coarse measurement coordinates of the target measurement point are calculated.

[0059] Step 203: The absolute distance measurement module 2 guides the distance measurement light beam to the center position of the optical reflection unit 7 according to the coarse coordinate, and measures the distance between the optical reflection unit 7 and the absolute distance measurement module 2.

[0060] Step 204: Establish a coordinate measurement model to calculate the accurate spatial coordinates of the target measurement point.

[0061] In step 201, the integrated measurement base station and the cooperative target are specifically constructed as follows:

[0062] The integrated measurement base station comprises a base station shell 1, an optoelectronic scanning module, and an absolute distance measurement module 2.

[0063] The optoelectronic scanning module comprises a rotor platform 3, a scanning laser 4, and a synchronous pulse laser 5. Two scanning lasers 4 are installed on the rotor platform 3 to realize full-circumferential space scanning. The synchronous pulse laser 5 is fixed around the base station shell 1, and the rotor platform 3 triggers the synchronous pulse laser 5 once every revolution.

[0064] The absolute distance measurement module 2 comprises an absolute laser distance meter, a light beam guiding mechanism, and a light beam centering feedback control mechanism. The absolute distance measurement module 2 is located below the optoelectronic scanning module. The absolute laser distance meter uses femtosecond laser distance measurement principle or frequency-modulated continuous wave distance measurement principle to realize high-precision absolute distance measurement. The light beam guiding mechanism deflects the distance measurement light beam emitted by the absolute laser distance meter at high speed based on a fast mirror and switches between multiple target units. The light beam centering feedback control mechanism obtains the offset of the returned light beam through the fast mirror and the optical reflection unit through a four-quadrant photodetector, adjusts the light beam guiding mechanism through a control unit, and forms a light beam adjustment closed-loop system to accurately align the distance measurement light beam with the target measurement point.

[0065] The cooperative target is provided with an optoelectronic receiving unit 6, an optical reflection unit 7, and a signal processing unit 8. The optoelectronic receiving units P1, P2, and P3 are fixed in an equilateral triangle on the cooperative target, used to receive two scanning light signals and a synchronous light signal and convert them into logic pulses. The optical reflection center S r is coplanar with the three optoelectronic receiving units and is fixed on the cooperative target. It reflects the distance measurement light beam so that it returns along the original path. The signal processing unit 8 is located inside the cooperative target and converts the output signal of the optoelectronic receiving unit 6 into the rotation angle of the scanning light plane.

[0066] In step 201, the positions of the optoelectronic scanning module and the absolute distance measurement module 2 on the measurement base station are calibrated as follows:

[0067] Step 2-1: Calibrate a high-precision control field using a laser tracker. The optoelectronic scanning module measures each control point, and a tracker coordinate system Ox T -X TY T Z T Coordinate system O of photoelectric scanning module S -X S Y S Z S Orientation parameters;

[0068] Step 2-2: Absolute ranging module 2 measures the distance between each control point and the ranging module, and uses the principle of polygon intersection to obtain the coordinates of the ranging origin, which is used as the origin O of the absolute ranging coordinate system. L The beam guiding mechanism rotates two axes while keeping the deflection angle of the other axis zero. It rotates multiple times to different angles, and a laser tracker measures the coordinates of the points along the path of the ranging beam. The Z-axis of the absolute ranging coordinate system is then established by fitting the plane normal vector. L and Y L The axis is determined according to the right-hand coordinate system. L The axis is used to obtain the tracker coordinate system O. T -X T Y T Z T Coordinate system O of the absolute ranging module L -X L Y L Z L Orientation parameters;

[0069] Steps 2-3: Use a laser tracker to unify the coordinate systems of the two modules, and obtain the coordinates O′ of the ranging origin in the coordinate system of the photoelectric scanning module. L (x l ,y l ,z l ).

[0070] Specifically, step 201, calibrating the positions of the photoelectric receiving unit and the optical reflecting unit on the cooperative target, involves using a laser tracker or image measuring instrument to calibrate the distance between every two photoelectric receiving units and the distance between the optical reflecting unit and each photoelectric receiving unit. Then:

[0071]

[0072] In the above formula, (x i ,y i ,z i i = 0 and i = 1, 2, 3 represent the spatial coordinates of the optical reflective unit and the three photoelectric receiving units on the cooperative target in the coordinate system of the photoelectric scanning module, respectively. ij This indicates the distance between two control points.

[0073] In step 202, the rotation angle θ of the two scanning light planes as they pass through each photoelectric receiving unit is obtained by the signal processing unit. mi(m = 1, 2; i = 1, 2, 3), the light plane coefficient of the corresponding position is obtained according to the rotation transformation:

[0074]

[0075] In the above formula, [a mi b mi c mi d mi ] T represents the light plane coefficient when the mth light plane rotates to the ith photoelectric receiving unit, [a m0 b m0 c m0 d m0 ] T represents the light plane coefficient of the mth light plane at the initial position.

[0076] Accordingly, six plane constraints are established, that is, each scanning light plane forms a light plane constraint at each photoelectric receiving unit:

[0077]

[0078] In addition, the distance between the photoelectric receiving unit and the optical reflection unit on the cooperative target also establishes six structure constraints, and the optimization equation of the spatial coordinates of the photoelectric receiving unit and the optical reflection unit is established, and the objective function is:

[0079]

[0080] For the above nonlinear optimization problem, the L-M algorithm is used for iterative solution to obtain the coarse measurement coordinates (x'0y'0z'0) of the target measurement point in the photoelectric scanning module coordinate system.

[0081] Wherein, step 203 converts the coarse measurement coordinates of the target measurement point in the photoelectric scanning module coordinate system to (x"0y"0z"0) in the absolute ranging module 2 coordinate system, and the pitch angle and azimuth angle of the target measurement point in the absolute ranging module 2 coordinate system are:

[0082]

[0083] The absolute ranging module 2 aligns the target measurement point according to the azimuth information to obtain the absolute distance L between the target point and the ranging origin. Wherein, step 204 introduces the distance between the target measurement point and the absolute ranging module as a constraint condition:

[0084] L 2 = (x l -x0) 2 +(y l -y0) 2 +(z l- z0) 2

[0085] In combination with the above-mentioned plane constraint condition, structure constraint condition and distance constraint condition, the optimization equation is established again, and the objective function is:

[0086]

[0087] The L-M algorithm is used to solve the nonlinear optimization problem by selecting a suitable iteration initial value, and accurate target measurement point space coordinates are obtained.

[0088] Those skilled in the art can understand that the accompanying drawings are only schematic diagrams of a preferred embodiment, and the above-mentioned embodiment numbers are only for description, not representing the advantages and disadvantages of the embodiments.

[0089] The above only describes the preferred embodiments of the present application, and does not limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A single-station multi-target spatial coordinate measurement method based on optoelectronic scanning and absolute ranging, characterized in that, The method comprises: The integrated measurement base station and the cooperative target are constructed, the relative positions of the photoelectric scanning module and the absolute distance measuring module on the measurement base station are calibrated, and the positions of the photoelectric receiving unit and the optical reflection unit on the cooperative target are calibrated; The rotation angle and the normal vector of the scanning light plane are obtained, the center position of the optical reflection unit is taken as a target measurement point, and the coarse measurement coordinates of the target measurement point are calculated; The absolute distance measuring module guides the distance measuring light beam to be aligned with the center position of the optical reflection unit according to the coarse measurement coordinates, and measures the distance between the optical reflection unit and the absolute distance measuring module; A coordinate measurement model is established, and the accurate spatial coordinates of the target measurement point are calculated; The photoelectric receiving unit, the optical reflection unit and the signal processing unit are arranged on the cooperative target; The photoelectric receiving unit is fixed on the cooperative target in an equilateral triangle shape, is used for receiving the scanning light signal and the synchronous light signal and converting into a logic pulse; the optical reflection unit is fixed on the cooperative target in a plane with the three photoelectric receiving units, reflects the distance measuring light beam so that the distance measuring light beam returns along the original path; and the signal processing unit is located inside the cooperative target, converts the output signal of the photoelectric receiving unit into the rotation angle of the scanning light plane; The rotation angle and the normal vector of the scanning light plane are obtained, the center position of the optical reflection unit is taken as a target measurement point, and the coarse measurement coordinates of the target measurement point are calculated; The rotation angle of each photoelectric receiving unit when two scanning light planes pass through the photoelectric receiving unit is obtained through the signal processing unit, the light plane normal vector of the corresponding position is obtained according to the rotation transformation, six plane constraint conditions are established according to this, six structure constraint conditions of the distance between the photoelectric receiving unit and the optical reflection unit on the cooperative target are established, and an optimization equation of the spatial coordinates of the photoelectric receiving unit and the optical reflection unit is established to be iteratively solved, so that the coarse measurement coordinates of the target measurement point in the photoelectric scanning module coordinate system are obtained; The rotation angle and the normal vector of the scanning light plane are obtained, the center position of the optical reflection unit is taken as a target measurement point, and the coarse measurement coordinates of the target measurement point are calculated; The distance between the target measurement point and the absolute distance measuring module is introduced as a constraint condition, the plane constraint condition and the structure constraint condition are combined, an optimization equation is established, and iterative optimization solving is performed again, so that the spatial coordinates of the target measurement point are obtained; The signal processing unit obtains the rotation angle of the two scanning light planes when passing through each photoelectric receiving unit The light plane coefficient of the corresponding position is obtained according to the rotation transformation. ； In the above formula, represents the optical plane coefficient of the mth optical plane when rotated to the ith photoelectric receiving unit, represents the optical plane coefficient of the mth optical plane at the initial position; According to this, six plane constraint conditions are established, that is, each scanning light plane forms an optical plane constraint at each photoelectric receiving unit: ； In addition, six structure constraint conditions of the distance between the photoelectric receiving unit and the optical reflection unit on the cooperative target are established, and an optimization equation of the spatial coordinates of the photoelectric receiving unit and the optical reflection unit is established, and the objective function is: ； For the above nonlinear optimization problem, the L-M algorithm is used to solve iteratively to obtain the coarse measurement coordinates of the target measurement point in the photoelectric scanning module coordinate system , is the distance between each two photoelectric receiving units and the distance between the optical reflecting unit and each photoelectric receiving unit.

2. The single station multi-target spatial coordinate measurement method based on photoelectric scanning and absolute ranging according to claim 1, characterized in that, The absolute distance measuring module comprises an absolute laser range finder, a light beam guiding mechanism and a light beam centering feedback control mechanism. The absolute distance measuring module is located below the photoelectric scanning module, the absolute laser range finder adopts femtosecond laser ranging principle or frequency-modulated continuous wave ranging principle to realize absolute distance measurement, the beam guiding mechanism deflects the ranging beam emitted by the absolute laser range finder based on a fast mirror and switches between multiple target units, the beam centering feedback control mechanism obtains the offset of the returned beam through the mirror and the optical reflection unit through a four-quadrant photoelectric detector, adjusts the beam guiding mechanism through a control unit, and constitutes a beam adjustment closed-loop system to align the ranging beam with the target measurement point.

3. The single station multi-target spatial coordinate measurement method based on photoelectric scanning and absolute ranging according to claim 1, characterized in that, The relative position of the photoelectric scanning module and the absolute distance measuring module on the calibration measurement base station is: A high-precision control field is constructed by using a laser tracker, the photoelectric scanning module measures each control point, and directional parameters of the tracker coordinate system and the photoelectric scanning module coordinate system are established according to the spatial resection principle; The absolute distance measuring module measures the distance between each control point and the distance measuring module, obtains the ranging origin coordinates by using the multi-lateration principle, takes the ranging origin coordinates as the origin of the absolute distance measuring coordinate system, rotates the two rotation axes of the beam guiding mechanism and keeps the deflection angle of the other rotation axis to be zero, rotates to different angles multiple times and measures the point coordinates on the light path of the ranging beam by using the laser tracker, establishes two axes of the absolute distance measuring coordinate system by fitting plane normal vectors, determines the other axis according to the right-hand coordinate system, and thus obtains the directional parameters of the tracker coordinate system and the absolute distance measuring module coordinate system; The directional parameters of the photoelectric scanning module coordinate system and the absolute distance measuring module coordinate system are calculated by using the directional parameters between the photoelectric scanning module coordinate system, the absolute distance measuring module coordinate system and the tracker coordinate system.

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