Surveying system, surveying method, and surveying program

Abstract

A surveying system (1) comprising: a target device (3) having a pole (14) and a target (15) of which the distance from the lower end of the pole is known; and a surveying device (2) capable of measuring the target. The lower end of the pole is matched with a prescribed measurement point (13). The surveying device is configured so as to: calculate an O-M vector linking the instrument center of the surveying device and the measurement position of the target, and an M-P vector linking the measurement position and the measurement point; calculate the angle ϕ formed by the O-M vector and a plane that is orthogonal to the M-P vector and passes through the measurement position; calculate, on the basis of the angle ϕ, the measurement error between the measurement position and the optical center of the target; correct the measurement position on the basis of the measurement error; and calculate, on the basis of the corrected measurement position, the three-dimensional coordinates of the measurement point.

Description

Surveying system, surveying method and surveying program

[0001] The present invention relates to a surveying system, a surveying method, and a surveying program that are capable of measuring the three-dimensional coordinates of a desired measurement point.

[0002] When surveying a desired measurement point, the survey is generally carried out using a retroreflective prism, etc. In prism surveying using a prism, for example, a pole with a prism mounted at a known position is installed at the measurement point, and the prism is leveled so that it is positioned vertically above the measurement point using a vial or the like, and then the prism is measured using a surveying device such as a total station.

[0003] However, when prism measurement is performed at a plurality of measurement points, leveling must be performed each time the measurement point is moved, which takes time for measurement and reduces work efficiency.

[0004] Furthermore, when the measurement point is a corner of a room, the pole cannot be leveled vertically. If the prism cannot be installed vertically above the measurement point, it is difficult to perform a survey using a prism.

[0005] Furthermore, there is also a surveying instrument that is equipped with an inclination angle detector on the pole, which detects the inclination angle of the pole and corrects the measurement value based on the detected inclination angle, making it possible to measure the corners of a room, etc. However, with this surveying instrument, there is a risk that errors will occur in the measurement results depending on the direction of the inclination.

[0006] Patent No. 6721479

[0007] The present invention provides a surveying system, a surveying method, and a surveying program that improve the measurement accuracy of measurement points.

[0008] The present invention relates to a surveying system having a target device which has a pole and a target whose distance from the bottom end of the pole is known, and a surveying instrument capable of measuring the target, wherein the bottom end of the pole is aligned with a predetermined measurement point, the surveying instrument calculates an O-M vector connecting the instrument center of the surveying instrument and the measurement position of the target, and an M-P vector connecting the measurement position and the measurement point, calculates the angle φ between the O-M vector and a plane which is perpendicular to the M-P vector and passes through the measurement position, calculates the measurement error between the measurement position and the optical center of the target based on the angle φ, corrects the measurement position based on the measurement error, and calculates the three-dimensional coordinates of the measurement point based on the corrected measurement position.

[0009] The present invention also relates to a surveying system configured so that the target device swings the pole while aligning the lower end of the pole with a predetermined measurement point, the surveying device measures the target at at least three points, calculates three-dimensional coordinates of virtual measurement points based on the measurement positions of each target, and calculates the MP vector based on the measurement positions of the targets and the virtual measurement points.

[0010] The present invention also relates to a surveying system in which the target device further has an inclination sensor, and the surveying device is configured to calculate the MP vector based on the measured position and the attitude of the pole detected by the inclination sensor.

[0011] The present invention also relates to a surveying system configured such that the surveying instrument calculates the degree of coincidence between the measurement point and the virtual measurement point as an accuracy, and when the accuracy meets a preset threshold, corrects the measurement position of each target, recalculates the virtual measurement point as a measurement point based on each corrected measurement position, and performs the measurement completion operation.

[0012] The present invention also relates to a surveying system configured such that the surveying device corrects all measurement positions of the target each time the virtual measurement point is calculated, recalculates the virtual measurement point based on the corrected measurement position, calculates the degree of coincidence between the measurement point and the virtual measurement point as accuracy, and when the accuracy meets a preset threshold, considers the virtual measurement point to be the measurement point and performs the measurement completion operation.

[0013] The present invention also relates to a surveying system in which the surveying instrument is configured to calculate the distance from the bottom end of the pole to the target as the radius, calculate the center of a sphere fitting to each measurement position as the measurement point, calculate a reference sphere normalized with the radius of the sphere set to 1, calculate the area of ​​the smallest curved surface that includes all the point clouds on the surface of the reference sphere, and calculate the accuracy based on a comparison between the curved surface and a preset reference curved surface.

[0014] The present invention also relates to a surveying system in which the surveying instrument further has a tracking function and is configured so that the surveying instrument can measure the target while tracking it.

[0015] The present invention also relates to a surveying system configured such that, each time the surveying device measures the target, it sequentially calculates spheres that fit to the measurement positions of at least three consecutively measured targets, and determines whether the target device has been installed at the measurement point based on whether the distance between the centers of each sphere converges within a predetermined threshold range.

[0016] The present invention also relates to a surveying method comprising the steps of: calculating, with the bottom end of the pole aligned with a predetermined measurement point, an O-M vector connecting the instrument center of the surveying instrument and the measurement position of a target attached to the top end of the pole, and an M-P vector connecting the measurement position and the measurement point; calculating the angle φ between the O-M vector and a plane that is perpendicular to the M-P vector and passes through the measurement position; calculating the measurement error between the measurement position and the optical center of the target based on the angle φ; correcting the measurement position based on the measurement error; and calculating the three-dimensional coordinates of the measurement point based on the corrected measurement position.

[0017] The present invention also relates to a surveying method that further includes the steps of swinging the pole while aligning the lower end of the pole with a predetermined measurement point and measuring the target at at least three points, calculating the three-dimensional coordinates of a virtual measurement point based on the measurement position of each target, and calculating the MP vector based on the measurement position of the target and the virtual measurement point.

[0018] The present invention also relates to a surveying method further comprising the steps of receiving the attitude of the pole from an inclination sensor provided on the pole, and calculating the MP vector based on the received attitude of the pole.

[0019] Furthermore, the present invention relates to a surveying program that causes the surveying instrument to execute the following processes: a process of calculating, with the bottom end of the pole aligned with a predetermined measurement point, an O-M vector connecting the instrument center of the surveying instrument and the measurement position of a target attached to the top end of the pole, and an M-P vector connecting the measurement position and the measurement point; a process of calculating the angle φ between the O-M vector and a plane that is perpendicular to the M-P vector and passes through the measurement position; a process of calculating the measurement error between the measurement position and the optical center of the target based on the angle φ; a process of correcting the measurement position based on the measurement error; and a process of calculating the three-dimensional coordinates of the measurement point based on the corrected measurement position.

[0020] According to the present invention, there is provided a surveying system having a target device which has a pole and a target whose distance from the bottom end of the pole is known, and a surveying instrument capable of measuring the target, wherein the bottom end of the pole is aligned with a predetermined measurement point, the surveying instrument calculates an O-M vector connecting the instrument center of the surveying instrument and the measurement position of the target, and an M-P vector connecting the measurement position and the measurement point, calculates an angle φ between the O-M vector and a plane which is perpendicular to the M-P vector and passes through the measurement position, calculates a measurement error between the measurement position and the optical center of the target based on the angle φ, corrects the measurement position based on the measurement error, and calculates the three-dimensional coordinates of the measurement point based on the corrected measurement position, so that even if a measurement error exists between the measurement position of the target measured by the surveying instrument and the optical center of the target, the measurement error can be corrected, and the measurement accuracy of the measurement point can be improved.

[0021] Furthermore, according to the present invention, with the bottom end of the pole aligned with a predetermined measurement point, the method includes the steps of: calculating an O-M vector connecting the instrument center of the surveying instrument and the measurement position of a target attached to the top end of the pole, and an M-P vector connecting the measurement position and the measurement point; calculating the angle φ between the O-M vector and a plane that is perpendicular to the M-P vector and passes through the measurement position; calculating a measurement error between the measurement position and the optical center of the target based on the angle φ; correcting the measurement position based on the measurement error; and calculating the three-dimensional coordinates of the measurement point based on the corrected measurement position.Therefore, even if a measurement error exists between the measurement position of the target measured by the surveying instrument and the optical center of the target, the measurement error can be corrected, and the measurement accuracy of the measurement point can be improved.

[0022] Furthermore, according to the present invention, with the bottom end of the pole aligned with a predetermined measurement point, the surveying instrument executes the following processes: a process of calculating an O-M vector connecting the instrument center of the surveying instrument and the measurement position of a target attached to the top end of the pole, and an M-P vector connecting the measurement position and the measurement point; a process of calculating the angle φ between the O-M vector and a plane that is perpendicular to the M-P vector and passes through the measurement position; a process of calculating a measurement error between the measurement position and the optical center of the target based on the angle φ; a process of correcting the measurement position based on the measurement error; and a process of calculating the three-dimensional coordinates of the measurement point based on the corrected measurement position.Therefore, even if a measurement error exists between the measurement position of the target measured by the surveying instrument and the optical center of the target, the measurement error can be corrected, and the measurement accuracy of the measurement point can be improved.

[0023] FIG. 1 is a schematic diagram showing a surveying system according to a first embodiment. FIG. 2 is a schematic block diagram showing a surveying device according to the first embodiment. FIG. 3(A) is an explanatory diagram showing the swing of a target device, and FIG. 3(B) is an explanatory diagram showing a sphere to be fitted to the measurement results. FIG. 4 is an explanatory diagram explaining how to calculate the accuracy of a measurement point according to the first embodiment. FIG. 5 is an explanatory diagram explaining the measurement position and the position of the optical center according to the first embodiment. FIG. 6 is a flowchart explaining measurement by the surveying system according to the first embodiment. FIG. 7 is a flowchart explaining measurement by the surveying system according to the second embodiment. FIG. 8 is a schematic diagram showing a surveying system according to a third embodiment.

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0025] First, referring to FIG. 1, a surveying system according to a first embodiment of the present invention will be described.

[0026] The surveying system 1 comprises a surveying device 2 and a target device 3. The surveying device 2 is, for example, a total station with a tracking function, and is composed of a leveling unit 5 attached to a tripod 4, and a surveying device main body 6 attached to the leveling unit 5 and capable of horizontal rotation relative to the leveling unit 5. The surveying device 2 is installed at a reference point having known three-dimensional coordinates.

[0027] The leveling unit 5 has a sensor (not shown) for detecting the inclination of the leveling unit 5 and a motor (not shown) for driving a leveling screw that levels the leveling unit 5, and is configured to automatically level the leveling unit 5 based on the detection results of the sensor.

[0028] The surveying instrument main body 6 has a telescope unit 7 that can rotate vertically relative to the surveying instrument main body 6. The telescope unit 7 also incorporates a distance measuring unit 8 (described later) and a tracking unit 9 (described later). The distance measuring unit 8 is configured to emit distance measuring light 11 on a distance measuring optical axis and measure the distance to the object to be measured based on the distance measuring light reflected by the object to be measured. The tracking unit 9 is configured to emit tracking light 12 on a tracking optical axis (on the distance measuring optical axis) that is coaxial with the distance measuring light 11 and perform tracking based on the reflected tracking light reflected by the object to be measured.

[0029] The target device 3 has a rod-shaped pole 14 installed at the measurement point 13 and a prism 15 as a target (measurement object) attached to the upper end of the pole 14. The lower end of the pole 14 is conical, with the diameter tapering downward, and the lower end is pointed. The prism 15 is, for example, a 360° full-circumference prism combining multiple retroreflective prisms 15a to 15n. The optical center of the prism 15 is located on the axis of the pole 14, and the distance from the lower end of the pole 14 to the optical center of the prism 15 is known. Note that in FIG. 1, a cross section of the prism 15 is shown as the prism 15.

[0030] Next, the configuration of the surveying device 2 will be described with reference to FIG.

[0031] The surveying instrument 2 has a horizontal rotation drive unit 16 for rotating the surveying instrument main body 6 relative to the leveling unit 5, a horizontal angle detector 17 for detecting the rotation angle (horizontal angle) of the surveying instrument main body 6, a vertical rotation drive unit 18 for rotating the telescope unit 7 relative to the surveying instrument main body 6, and a vertical angle detector 19 for detecting the rotation angle (vertical angle) of the telescope unit 7. The surveying instrument 2 also has an arithmetic and control unit 21, a memory unit 22, a display unit 23, and an operation unit 24.

[0032] The horizontal rotation drive unit 16 and the vertical rotation drive unit 18 constitute the drive unit of the surveying device 2, and the horizontal angle detector 17 and the vertical angle detector 19 constitute the angle measurement unit for detecting the irradiation direction of the distance measuring light 11.

[0033] The arithmetic control unit 21 may be a CPU specialized for this embodiment, or a general-purpose CPU, an embedded CPU, a microprocessor, etc. The storage unit 22 may be a semiconductor storage memory such as RAM, ROM, Flash ROM, or DRAM, a magnetic storage memory such as HDD, or an optical storage memory such as CD-ROM.

[0034] The storage unit 22 stores a sequence program for controlling the measurement operation, a distance measurement program for calculating the distance by a distance measurement operation, an angle measurement program for calculating the irradiation direction (angle) of the distance measurement light 11 and the tracking light 12 based on the detection results of the horizontal angle detector 17 and the vertical angle detector 19, a measurement program for calculating the three-dimensional coordinates of the prism 15 based on the distance and angle, a leveling program for making the leveling unit 5 perform leveling, a tracking program for making the tracking unit 9 track the prism 15, and a program for calculating the three-dimensional coordinates of a virtual measurement point based on measurement results (distance measurement results and angle measurement results) of at least three different points on the prism 15. various programs are stored, such as a calculation program for calculating the degree of coincidence between the measurement point 13 and the virtual measurement point as accuracy, an accuracy calculation program for calculating the degree of coincidence between the measurement point 13 and the virtual measurement point as accuracy, a judgment program for determining whether the calculated accuracy satisfies a preset threshold value, a correction program for correcting the calculation results (three-dimensional coordinates) of the virtual measurement point, a calculation program for calculating the three-dimensional coordinates of the measurement point 13 based on the corrected virtual measurement point, a notification program for notifying of measurement completion, a drive control program for controlling the horizontal rotation drive unit 16, the vertical rotation drive unit 18, etc., and a display program for displaying measurement results, etc. on the display unit 23.

[0035] The storage unit 22 also stores data such as measurement data (distance measurement data and angle measurement data) obtained when measuring the prism 15, and three-dimensional coordinate data of the measurement point 13 calculated based on the measurement data. It also stores thresholds for determining the accuracy of the position of the center of the sphere relative to the measurement point 13, as will be described later, and approximate formulas for correction. The accuracy indicates how closely the position of a virtual measurement point 13a determined by calculation matches the measurement point 13, i.e., the degree of agreement between the measurement point 13 and the virtual measurement point 13a. The calculation control unit 21 deploys and executes various programs stored in the storage unit 22 to perform various processes.

[0036] Next, measurements using the surveying system 1 will be described with reference to the flowcharts of FIGS. 3(A), 3(B), 4, 5 and 6.

[0037] STEP 01 First, the calculation control unit 21 causes the telescope unit 7 to collimate the prism 15 and start measuring and tracking the prism 15 .

[0038] The surveying device 2 measures the prism 15 (measures distance and angle) at a predetermined interval, for example, 20 Hz, while tracking the prism 15. Therefore, three-dimensional coordinates (point cloud) of a plurality of points along the trajectory 25 of the prism 15 are obtained. The measurement interval is not limited to 20 Hz, and an appropriate interval such as 10 Hz or 30 Hz can be selected.

[0039] In measuring the prism 15, there may be a mismatch between the timing of measuring the distance and the timing of measuring the angle for the prism 15. In this case, the measurement accuracy of the prism 15 can be improved by discarding the measurement results with the mismatched timing.

[0040] STEP 02 With the surveying device 2 tracking the prism 15 , the operator carries the target device 3 toward the predetermined measurement point 13 .

[0041] STEP 03: The distance (offset length R) from the bottom end of the pole 14 to the optical center of the prism 15 is known. The calculation control unit 21 calculates a sphere 26 with a radius equal to the offset length R and fits the sphere 26 to a group of at least three consecutive points set in advance. As shown in FIG. 3B , when fitting the sphere 26 based on four points, for example, in the nth measurement, the sphere 26 is fitted to four points: the prism 15n measured in the nth measurement, the prism 15n-1 measured in the n-1th measurement, the prism 15n-2 measured in the n-2th measurement, and the prism 15n-3 measured in the n-3th measurement. That is, the sphere 26 is sequentially fitted to the four consecutively measured points.

[0042] Alternatively, the calculation control unit 21 calculates the sphere 26 having the offset length R as its radius and passing through the three-dimensional coordinates of the measured four points of the prisms 15n, 15n-1, 15n-2, and 15n-3.

[0043] Moreover, the calculation control unit 21 sequentially calculates the sphere 26 that fits to the four points and calculates the center of the sphere 26 every time the prism 15 is measured.

[0044] STEP 04 The calculation control unit 21 determines whether the sphere 26 that fits the four points exists, and whether the distance between the centers of the spheres 26 that are sequentially calculated converges to a preset threshold value or less.

[0045] If the sphere 26 fitting to the four points cannot be calculated, or if the centers of the successively calculated spheres 26 do not converge to or below the threshold, the calculation control unit 21 determines that the target device 3 is moving and discards the measurement results. After discarding the measurement results, calculation of the sphere 26 and calculation of the center of the sphere 26 continue.

[0046] Furthermore, if a sphere 26 exists that fits the four points and the center of the sphere 26 converges below a predetermined threshold, the calculation control unit 21 determines that the target device 3 is installed at the measurement point 13, i.e., the lower end of the pole 14 coincides with the measurement point 13.

[0047] STEP 05 After setting up the target device 3, the operator swings the target device 3 in a predetermined direction at a predetermined angle with the lower end of the pole 14 aligned with the measurement point 13. For example, as shown in Fig. 3(A), the operator swings the target device 3 in a cross shape at ±15°.

[0048] The swing of the target device 3 is not limited to a cross shape. For example, the target device 3 may be tilted so that the prism 15 describes a circle, or so that the prism 15 describes a figure eight. Furthermore, the prism 15 may be tilted so that it describes a triangular trajectory and passes through one point within the triangle. In other words, it is sufficient that the swing direction has a two-dimensional spread. Furthermore, the tilt angle of the target device 3 is not limited to ±15°, but may be greater than or less than 15°.

[0049] From the time when it is determined that the target device 3 is placed at the measurement point 13, the calculation control unit 21 stores and accumulates the measurement results of the prism 15 as a point cloud in the storage unit 22 one after another.

[0050] STEP 06 The calculation control unit 21 calculates the sphere 26 that fits to the accumulated point cloud, and calculates the center of the sphere 26, that is, the bottom end of the pole 14, as a virtual measurement point 13a.

[0051] STEP 07 After calculating the virtual measurement point 13a, the calculation control unit 21 calculates the accuracy A of the virtual measurement point 13a. Here, the accuracy A of the virtual measurement point 13a is a value indicating the degree of agreement between the calculated virtual measurement point 13a and the actual measurement point 13a.

[0052] 3B, for example, the calculation control unit 21 calculates the accuracy A of the measurement point 13 based on the spread of the measurement results (point cloud) of the prism 15 at four consecutive points on the sphere 26 having the virtual measurement point 13a as its center and the offset length R as its radius. That is, after the target device 3 is installed, the calculation control unit 21 calculates the accuracy A of the virtual measurement point 13a based on the spread of all point clouds stored in the memory unit 22.

[0053] In the above method, the calculation control unit 21 first normalizes the sphere 26 to a reference sphere 27 as shown in Fig. 4. The reference sphere 27 is normalized with an offset length R = 1, is centered at the virtual measurement point 13a, and has a radius of 1. That is, the three-dimensional coordinates of the point cloud obtained by measuring the prism 15 and located on the surface of the sphere 26 are converted into a point cloud 28 located on the surface of the reference sphere 27 and centered at the virtual measurement point 13a.

[0054] Next, the calculation control unit 21 calculates the area S of the smallest curved surface 29 that includes all of the point cloud 28 located on the surface of the reference sphere 27. The curved surface 29 is a curved surface that forms a part of the surface of the reference sphere 27. The storage unit 22 stores a reference curved surface 31 for comparison with the area S. The reference curved surface 31 is a curved surface that forms a part of the surface of the reference sphere 27 and has an area B. Here, the area B is a size that allows a desired fitting accuracy to be obtained when the reference sphere 27 is fitted to the point cloud 28.

[0055] The accuracy A of the virtual measurement point 13 a can be expressed as accuracy A = area S / area B. The calculation control unit 21 calculates the accuracy A of the virtual measurement point 13 a based on the area S of the curved surface 29 and the area B of the reference curved surface 31.

[0056] STEP 08: Once the accuracy A of the virtual measurement point 13a has been calculated, the calculation control unit 21 determines whether the accuracy A of the virtual measurement point 13a satisfies a predetermined threshold, for example, whether it is equal to or greater than 1. That is, the calculation control unit 21 determines whether the area S is equal to or greater than the area B. When the accuracy is equal to or greater than 1, it can be determined that the reference sphere 27 has been fitted to the point cloud 28 with the desired fitting accuracy.

[0057] If it is determined that the accuracy A is less than 1, i.e., the size of the area S is smaller than the area B and does not satisfy the threshold value, the target device 3 is swung more greatly so as to increase the area S, and the processing of STEP: 05 to STEP: 08 is executed again. That is, every time a measurement of the prism 15 is performed, the fitting of the sphere 26 is executed for each measurement result, and the calculation of the virtual measurement point 13a and the fitting of the sphere 26 are repeated until the accuracy becomes 1 or more.

[0058] An alarm may be used to notify the operator whether the accuracy A has met a threshold value. For example, the sound may be made lower as the accuracy A deviates from 1 and higher as the accuracy A approaches 1, or the sound may be generated intermittently, with the intervals between the sounds increasing as the accuracy A deviates from 1 and narrowing as the accuracy A approaches 1. Alternatively, a light may be flashed, with the frequency of the flashing increasing as the accuracy A deviates from 1 and the frequency of the flashing decreasing as the accuracy A approaches 1, or the color of the light may be changed when the accuracy A reaches 1.

[0059] Also, as an alarm, the value of area S / area B may be displayed as a percentage on the display unit 23, and may become 100% when area S / area B≦1. Furthermore, as an alarm, when accuracy A meets a threshold value, the process may simply proceed to the next step, or the measurement result may be displayed on the display unit 23. It goes without saying that various actions to indicate the completion of measurement, such as sound, light, display, etc., may be combined.

[0060] STEP 09 If it is determined that the accuracy A is 1 or more, that is, the size of the area S is equal to or larger than the area B and satisfies the threshold value, the calculation control unit 21 determines that the virtual measurement point 13a coincides or approximately coincides with the measurement point 13, and performs correction for the measurement point 13.

[0061] 5, the measurement position M measured as the center of the prism 15 by the surveying instrument 2 does not necessarily coincide with the actual center position (optical center) M' of the prism 15. For example, if the apparent direction of the prism 15 changes, the incident position of the distance measuring light 11 on the prism 15 also changes, and therefore a deviation (measurement error) occurs between the reflection position of the distance measuring light 11 within the prism 15, i.e., the measurement position M, and the center position M' of the prism 15.

[0062] Let O be the instrument center of the surveying instrument 2 installed at the reference point, M be the measurement position of the prism 15 measured by the surveying instrument 2, M' be the position of the actual center (optical center) of the prism 15, and P be the calculated virtual measurement point 13a, i.e., the position of the tip (bottom end) of the pole 14. The directional vector connecting the instrument center O and measurement position M is the O-M vector 32, the directional vector connecting measurement position M and measurement point P is the M-P vector 33, and the directional vector connecting measurement position M and the prism center M' is the M-M' vector 34. Note that the three-dimensional coordinates of the reference point are known, and the height of the surveying instrument 2, i.e., the height of the instrument center O, is also known, so the three-dimensional coordinate of the instrument center O is also known. Furthermore, the slope of the O-M vector 32 can be calculated based on the three-dimensional coordinates of the instrument center O and the measurement position M, and the M-P vector 33 can be calculated based on the three-dimensional coordinates of the measurement position M and the measurement point P.

[0063] In this case, if the angle between the O-M vector 32 and a plane that is perpendicular to the M-P vector 33 and passes through the measurement position M is φ, and the angle between the O-M vector 32 and the M-P vector 33 is θ, the angle φ can be calculated as φ = 90° - θ.

[0064] The calculation control unit 21 calculates the distance (measurement error) between the measurement position M and the prism center M' based on the angle φ, that is, the measurement error Δe in the direction of the MP vector 33. As a method for calculating Δe, for example, the method for calculating the measurement error shown in Patent Document 1 can be used.

[0065] When there is a difference in height between the surveying device 2 and the prism 15, which has a structure in which rotation in the axial direction of the pole 14 is fixed, the measurement error Δe is uniquely determined by the angle φ, the size of the prism 15, the refractive index of the prism 15, the inclination angle with respect to the incident surface of the prism 15, and the horizontal distance between the vertex of each retroreflective prism 15a to 15n and the optical center M' of the prism 15.

[0066] On the other hand, parameters other than the angle φ can be obtained from the specifications of the prism 15 used and can be substituted, so the measurement error Δe of the prism 15 can be expressed as a function of the angle φ only, i.e., Δe = e(φ).

[0067] The measurement error Δe can be divided into a horizontal measurement error Δd and a vertical measurement error Δh. Here, it is known that the measurement error Δh is approximately proportional to the magnitude of the angle φ, and the measurement error Δh can be approximated by a linear function of the angle φ. It is also known that the measurement error Δd is approximately a quadratic function of the angle φ, and the measurement error Δd can be approximated by a quadratic function of the angle φ.

[0068] Furthermore, Δd and Δh depend on the specifications of the prism 15, such as the size and refractive index, the inclination angle of the incident surface of the prism 15 with respect to the optical axis of the distance measuring light, and the angle φ. Therefore, by calculating in advance approximate formulas for the measurement errors Δd and Δh based on the specifications of the prism 15 and storing them in the memory unit 22, the measurement errors Δd and Δh can be easily calculated based on the approximate formulas. The calculation control unit 21 calculates the measurement errors Δd and Δh based on the approximate formulas, and calculates the measurement error Δe based on the measurement errors Δd and Δh.

[0069] Once the measurement error Δe is calculated, the calculation control unit 21 corrects the measurement results (three-dimensional coordinates) of all of the point clouds 28 stored and accumulated in the memory unit 22, i.e., for all measurement positions M, by the measurement error Δe in the direction of the MP vector 33, and updates the three-dimensional coordinates of the measurement positions M. The updated measurement positions M are saved in the memory unit 22 as the three-dimensional coordinates of the optical center M'. Note that the three-dimensional coordinates of the measurement positions M are not overwritten by the three-dimensional coordinates of the optical center M'. That is, the memory unit 22 stores the measured three-dimensional coordinates of the measurement positions M and the corrected and updated three-dimensional coordinates of the optical center M'.

[0070] STEP 10: The calculation control unit 21 calculates the sphere 26 that fits to each corrected measurement position M, i.e., each optical center M′, and recalculates the center of the sphere 26 as the three-dimensional coordinate of the virtual measurement point 13 a. The calculated three-dimensional coordinate of the virtual measurement point 13 a is stored in the memory unit 22 as the measurement point 13.

[0071] The calculated measurement point 13 is calculated in the same manner as the virtual measurement point 13a in STEP: 06, but since it is determined in STEP: 08 that the accuracy A satisfies the threshold value, the recalculated three-dimensional coordinates of the center of the sphere 26 can be regarded as the three-dimensional coordinates of the measurement point 13.

[0072] STEP 11: When the measurement of the measurement point 13 is completed, the calculation control unit 21 performs an operation to complete the measurement. The operation to complete the measurement may be, for example, to notify the operator of the completion of the measurement by an audible alarm or an optical alarm. The above-mentioned alarms may be issued from the surveying device 2 or from an alarm notification mechanism separately provided in the target device 3.

[0073] If there are other measurement points to be measured based on the alarm notification, the operator repeats the processing of STEP 02 to STEP 11. If there are no other measurement points to be measured, the measurement processing ends.

[0074] Furthermore, if the recalculation of the center of the sphere 26 is performed immediately and in a short time after determining whether the accuracy A meets the threshold value in STEP: 08, the notification of measurement completion in STEP: 11 may be omitted.

[0075] As described above, in the first embodiment, while the surveying device 2 is tracking and measuring the prism 15, the three-dimensional coordinates of the measurement point 13 can be calculated simply by aligning the lower end of the pole 14 with the measurement point 13 and swinging the target device 3 so that it has a two-dimensional spread.

[0076] Therefore, it is not necessary to level the target device 3 so that the prism 15 is positioned vertically above the measurement point 13, thereby shortening the work time. Also, it is possible to measure the measurement point 13 where the target device 3 cannot be installed vertically, such as on a wall or in a corner of a room, thereby improving work efficiency.

[0077] In addition, in the first embodiment, the calculation control unit 21 automatically determines whether the target device 3 is installed at the measurement point 13 based on whether there is a sphere 26 that fits at least three points measured consecutively and whether the centers of the spheres 26 converge.

[0078] Therefore, there is no need to notify the surveying device 2 of the completion of installation every time the target device 3 is installed at the measurement point 13, so that the work time can be shortened and improved.

[0079] When the sphere 26 is fitted to three points, two three-dimensional coordinates of the center of the sphere 26, i.e., the measurement point 13 where the target device 3 is installed, can be obtained. On the other hand, when measuring a floor, for example, the top and bottom of the prism 15 and the bottom end of the pole 14 are clear, the three-dimensional coordinates of the measurement point 13 can be uniquely determined.

[0080] Furthermore, in the first embodiment, it is possible to calculate the accuracy indicating the degree to which the calculated virtual measurement point 13a matches the actual measurement point 13, and only calculation results where the accuracy meets the threshold (is 1 or greater) are adopted, thereby enabling highly accurate measurements of the measurement point 13.

[0081] In the first embodiment, a measurement error Δe, which is the amount of deviation between the measurement position M measured by the surveying instrument 2 and the optical center M' of the prism 15, is calculated based on the specifications of the prism 15 and the angle φ between the O-M vector 32 and a plane perpendicular to the M-P vector 33, and the measurement result (measurement position M) is corrected based on the measurement error Δe.

[0082] Therefore, the deviation between the measurement position and the optical center of the prism 15 due to the apparent direction of the prism 15 as seen from the surveying device 2 can be corrected, and the calculation accuracy of the center of the sphere 26, i.e., the measurement point 13, can be further improved.

[0083] In the first embodiment, when a start command is input, measurement and tracking are continuously performed even when the target device 3 is moved or set up. On the other hand, it is also possible to perform only tracking of the prism 15 when the target device 3 is moved, and measure the prism 15 after the target device 3 is set up.

[0084] In addition, in the first embodiment, it is determined whether the target device 3 is moving or has been placed at the measurement point 13 based on whether the sphere 26 exists that fits to a point group of at least three consecutive points, or whether the center of the sphere 26 that is sequentially fitted to the three points converges to a predetermined threshold value or less each time the prism 15 is measured.

[0085] On the other hand, while tracking the prism 15, the surveying device 2 measures the prism 15 at predetermined time intervals, for example every 2 seconds, and each time the calculation control unit 21 measures the prism 15, it calculates the center of the sphere 26 that fits the measurement results of at least three consecutive measurements of the prism 15 as the virtual measurement point 13a, and when the accuracy A of the virtual measurement point 13a meets a predetermined threshold, it may be determined that the target device 3 has been installed at the measurement point 13.

[0086] Alternatively, while tracking the prism 15, the surveying device 2 measures the prism 15 at predetermined time intervals, and each time the calculation control unit 21 measures the prism 15, it calculates the center of the sphere 26 that fits the measurement result from a predetermined time ago or a predetermined number of times ago (for example, 5 seconds ago or 5 times ago) as the virtual measurement point 13a, and when the accuracy A of the virtual measurement point 13a meets a predetermined threshold, it determines that the target device 3 has been placed at the measurement point 13, and calculates the center of the sphere 26 that fits the latest measurement result as the measurement point 13.

[0087] In either case, simply by installing the target device 3 at the measurement point 13, measurement of the measurement point 13 is performed automatically, so after installing the target device 3, there is no need to instruct the surveying device 2 to start measurement, which improves workability.

[0088] It should be noted that, once it is determined that the target device 3 has been placed at the measurement point 13, the measurement of the measurement point 13 may be started after a predetermined time has elapsed. That is, after the predetermined time has elapsed, the calculation control unit 21 may perform the processes of STEP: 05 to STEP: 11.

[0089] Furthermore, the calculation of the measurement error Δe in the first embodiment and the correction of the measurement position M using the measurement error Δe can be applied to other embodiments as well. For example, when the target device 3 is leveled in a vertical position, the MP vector 33 becomes a vertical vector, which eliminates the need for calculation, and therefore the measurement error Δe can be easily calculated.

[0090] Next, a second embodiment of the present invention will be described with reference to the flowchart of FIG.

[0091] In FIG. 7, STEP 21 to STEP 26 are the same as STEP 01 to STEP 06 in FIG. 6 of the first embodiment, STEP 27 and STEP 28 are the same as STEP 09 and STEP 10, and STEP 29 to STEP 31 are the same as STEP 07, STEP 08 and STEP 11.

[0092] That is, the timing of correcting the measurement results of the prism 15 (see FIG. 1) and the timing of recalculating the center of the sphere 26 (see FIG. 3) are different from those in the first embodiment.

[0093] In the second embodiment, the calculation control unit 21 (see FIG. 2) calculates the sphere 26 that fits to the accumulated point cloud 28 (see FIG. 4), and corrects the measurement result (measurement position M) of the prism 15 each time the calculation control unit 21 calculates the center of the sphere 26 as the virtual measurement point 13a (STEP: 27).The calculation control unit 21 also recalculates the center of the sphere 26 based on the corrected and updated measurement position M, i.e., the optical center M' (STEP: 28).

[0094] After recalculating the center of the sphere 26, the calculation control unit 21 calculates accuracy A using the calculated center of the sphere 26 as the virtual measurement point 13a (STEP: 29), and determines whether accuracy A exceeds a predetermined threshold (STEP: 30). If accuracy A exceeds the predetermined threshold, the calculation control unit 21 instructs the operator to complete the measurement (STEP: 31), and ends the measurement. If accuracy A does not exceed the predetermined threshold, STEP: 25 to STEP: 30 are executed again.

[0095] In the first embodiment, an alarm may be issued after the accuracy A meets a predetermined threshold value, but in the second embodiment, an alarm may be issued as an action to complete measurement.

[0096] In the second embodiment, the three-dimensional coordinates of the measurement point 13 where the pole 14 (see FIG. 1) is installed can be calculated simply by swinging the target device 3 (see FIG. 1). This eliminates the need to level the target device 3, thereby shortening the work time and improving the work efficiency.

[0097] Furthermore, each time the three-dimensional coordinates of the virtual measurement point 13a are calculated, all measurement results (measurement position M) are corrected and the virtual measurement point 13a is recalculated based on the corrected measurement position, thereby further improving the accuracy (precision) of the virtual measurement point 13a.

[0098] Furthermore, whether the target device 3 has been installed at the measurement point 13 is automatically determined based on whether the center of the sphere 26 converges, so there is no need to input the start and end of measurement for each measurement point 13, thereby shortening and improving work time.

[0099] Furthermore, since the amount of deviation between the measurement position of the prism 15 and the optical center of the prism 15 can be calculated as a measurement error Δe, even if the target device 3 is tilted and the measurement position of the prism 15 is deviated from the optical center of the prism 15, the three-dimensional coordinates of the optical center of the prism 15 can be obtained, and the measurement accuracy of the measurement point 13 can be further improved.

[0100] Next, a third embodiment of the present invention will be described with reference to Fig. 8. In Fig. 8, the same components as those in Fig. 1 are given the same reference numerals, and the description thereof will be omitted.

[0101] In the third embodiment, the target device 3 has an inclination sensor 35 provided midway on the pole 14. The inclination sensor 35 is an IMU that includes, for example, an acceleration sensor or a gyro sensor, and is capable of detecting the attitude of the pole 14, i.e., the inclination angle and inclination direction of the pole 14. In addition, the target device 3 has a communication unit (not shown), and is capable of transmitting the inclination angle and inclination direction detected by the inclination sensor 35 to the surveying device 2.

[0102] The surveying device 2 (arithmetic and control unit 21) calculates the O-M vector 32 and the M-P vector 33 in the same manner as in the first and second embodiments, based on the measurement results of the prism 15 and the tilt angle and tilt direction of the pole 14 received from the target device 3, and calculates the angle φ formed between the O-M vector 32 and a plane that is perpendicular to the M-P vector 33 and passes through the measurement position M. In addition, the arithmetic and control unit 21 calculates the measurement error Δe between the measurement position M of the prism 15 measured by the surveying device 2 and the optical center M' of the prism 15, based on the angle φ.

[0103] The calculation control unit 21 displaces the pole 14 downward from the measurement position M along the inclination direction of the pole 14, i.e., along the MP vector 33, by Δe from the measurement position M, and calculates the three-dimensional coordinates of the optical center M'.

[0104] In addition, the calculation control unit 21 measures the three-dimensional coordinates of the measurement point 13 where the target device 3 is installed based on the three-dimensional coordinates of the optical center M', the known distance from the optical center of the prism 15 to the bottom end of the pole 14, and the inclination angle and inclination direction of the pole 14 received from the target device 3.

[0105] In the third embodiment as well, the amount of deviation between the measurement position M and the optical center M' can be calculated as a measurement error Δe based on the measurement result of the prism 15 and the tilt angle and tilt direction of the pole 14. Therefore, even if the target device 3 is tilted and the measurement position M of the prism 15 is misaligned from the optical center M' of the prism 15, the three-dimensional coordinates of the optical center of the prism 15 can be obtained, and the measurement accuracy of the measurement point 13 can be improved.

[0106] Furthermore, since it is not necessary to set the target device 3 in a vertical position every time the target device 3 is placed at the measurement point 13, the measurement time can be reduced and workability can be improved.

[0107] In the third embodiment, the target device 3 is provided with the tilt sensor 35, and the measurement error Δe is calculated based on the measurement results of the prism 15 and the detection results of the tilt sensor 35, i.e., the tilt angle and tilt direction of the pole 14. On the other hand, if the attitude of the pole 14, i.e., the tilt angle and tilt direction, can be detected or calculated using a device other than the tilt sensor 35, the measurement error Δe, which is the amount of deviation between the measurement position M of the prism 15 and the optical center M' of the prism 15 of the present invention, can be calculated, and the measurement results of the prism 15 can be corrected.

[0108] REFERENCE SIGNS LIST 1 Surveying system 2 Surveying device 3 Target device 8 Distance measuring unit 9 Tracking unit 11 Distance measuring light 12 Tracking light 13 Measurement point 14 Pole 15 Prism 21 Arithmetic control unit 22 Memory unit 26 Sphere 28 Point cloud 32 O-M vector 33 M-P vector 35 Tilt sensor

Claims

1. A surveying system having a target device having a pole and a target whose distance from the bottom end of the pole is known, and a surveying instrument capable of measuring the target, wherein the bottom end of the pole is aligned with a predetermined measurement point, the surveying instrument calculates an O-M vector connecting the instrument center of the surveying instrument and the measurement position of the target, and an M-P vector connecting the measurement position and the measurement point, calculates an angle φ between the O-M vector and a plane that is perpendicular to the M-P vector and passes through the measurement position, calculates a measurement error between the measurement position and the optical center of the target based on the angle φ, corrects the measurement position based on the measurement error, and calculates the three-dimensional coordinates of the measurement point based on the corrected measurement position.

2. The surveying system of claim 1, wherein the target device is configured to swing the pole while aligning the lower end of the pole with a specified measurement point, the surveying instrument measures the target at at least three points, calculates three-dimensional coordinates of a virtual measurement point based on the measurement positions of each target, and calculates the M-P vector based on the measurement positions of the target and the virtual measurement point.

3. A surveying system according to claim 1, wherein the target device further comprises a tilt sensor, and the surveying device is configured to calculate the M-P vector based on the measured position and the attitude of the pole detected by the tilt sensor.

4. A surveying system as claimed in claim 2, wherein the surveying device is configured to calculate the degree of coincidence between the measurement point and the virtual measurement point as an accuracy, and when the accuracy meets a preset threshold value, correct the measurement position of each target, recalculate the virtual measurement point as the measurement point based on each corrected measurement position, and perform an operation to complete the measurement.

5. A surveying system as claimed in claim 2, wherein the surveying device is configured to correct all measurement positions of the target each time the virtual measurement point is calculated, recalculate the virtual measurement point based on the corrected measurement positions, calculate the degree of coincidence between the measurement point and the virtual measurement point as an accuracy, and when the accuracy meets a preset threshold value, regard the virtual measurement point as the measurement point and perform an operation to complete the measurement.

6. A surveying system according to claim 4 or 5, wherein the surveying device is configured to take the distance from the bottom end of the pole to the target as a radius, calculate the center of a sphere fitting to each measurement position as the measurement point, calculate a reference sphere normalized with the radius of the sphere set to 1, calculate the area of ​​the smallest curved surface that includes all the points on the surface of the reference sphere, and calculate the accuracy based on a comparison between the curved surface and a preset reference curved surface.

7. A surveying system according to claim 6, wherein said surveying instrument further has a tracking function, and said surveying instrument is configured to be able to measure said target while tracking it.

8. The surveying system of claim 7, wherein the surveying device is configured to sequentially calculate spheres fitting to the measurement positions of at least three consecutively measured targets each time the target is measured, and to determine whether the target device is installed at the measurement point based on whether the distance between the centers of each sphere converges within a preset threshold range.

9. A surveying method comprising the steps of: calculating, while aligning the bottom end of a pole with a specified measurement point, an O-M vector connecting the instrument center of a surveying instrument and a measurement position of a target attached to the top end of the pole, and an M-P vector connecting said measurement position and the measurement point; calculating the angle φ between said O-M vector and a plane that is perpendicular to said M-P vector and passes through said measurement position; calculating the measurement error between said measurement position and the optical center of the target based on said angle φ; correcting the measurement position based on the measurement error; and calculating the three-dimensional coordinates of the measurement point based on the corrected measurement position.

10. The surveying method of claim 9, further comprising the steps of: swinging the pole while aligning the lower end of the pole with a predetermined measurement point, and measuring the target at at least three points; calculating three-dimensional coordinates of a virtual measurement point based on the measurement positions of each target; and calculating the M-P vector based on the measurement positions of the targets and the virtual measurement point.

11. The surveying method according to claim 9, further comprising the steps of: receiving the attitude of said pole from an inclination sensor provided on said pole; and calculating said MP vector based on the received attitude of said pole.

12. A surveying program that causes the surveying instrument to execute the following processes while aligning the bottom end of the pole with a specified measurement point: calculating an O-M vector connecting the instrument center of the surveying instrument and the measurement position of a target attached to the top end of the pole, and an M-P vector connecting the measurement position and the measurement point; calculating the angle φ between the O-M vector and a plane that is perpendicular to the M-P vector and passes through the measurement position; calculating the measurement error between the measurement position and the optical center of the target based on the angle φ; correcting the measurement position based on the measurement error; and calculating the three-dimensional coordinates of the measurement point based on the corrected measurement position.

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