Laser tracker based measurement system with inertial measurement unit

Abstract

The invention relates to a laser tracker based measuring system with an inertial measurement unit, in particular to a laser tracker based measuring system with a measuring aid having an inertial measurement unit (IMU). The measuring system is designed for determining the coordinates of surface points scanned by means of the measuring aid.

Description

Technical Field

[0001] This invention relates to a measurement system based on a laser tracker, the system having a measurement auxiliary device and a measurement auxiliary detection unit for detecting and tracking the measurement auxiliary device. The measurement system is configured to determine the coordinates of surface points scanned by the measurement auxiliary device. Background Technology

[0002] In object measurement technology, various measurement systems are known for determining the 3D coordinates of a point on an object's surface, also known as a surface point. Each system is based on the use of a specific measurement aid, which has a measuring head / sensor that scans the object's surface. The measurement task, and particularly its requirements for measurement accuracy / speed, fundamentally dictates the selection of the measurement aid. Measurement aids exist for both tactile and non-contact scanning. A tactile scanning measurement aid, for example, has a needle-shaped measuring probe with a ruby ​​ball mounted at one end. The ruby ​​ball is brought into contact with the point on the object's surface, and the measurement system determines the 3D coordinates of that point based on this contact. A non-contact scanning measurement aid, such as a laser scanner, has a radiation source that emits detection radiation, in which the point on the object's surface is irradiated by the detection radiation, and the irradiated point is reflected back, and the measurement system determines the 3D coordinates of that point based on this reflection.

[0003] Such tactile scanning and / or non-contact scanning measurement aids can be used in conjunction with coordinate measuring machines (CMMs), automatically guided kinematic chains, or robotic arms, or can be designed for manual operation by the user.

[0004] High-precision determination of the 3D coordinates of surface scanning points is extremely important for determining the position and orientation of measurement auxiliary devices. Summary of the Invention

[0005] Therefore, one objective of the present invention is to provide a measurement system that allows for highly accurate determination of the 3D coordinates of a point on a surface to be measured.

[0006] Another objective of the present invention is to provide a flexible measurement system, wherein the measurement aid can be machine-operated and / or manually operated and allows for efficient measurement of surface points.

[0007] Another objective of this invention is to provide a measurement system that allows for simple and intuitive operation.

[0008] The measurement system according to the invention is based on a laser tracker and is designed to determine the coordinates, particularly the 3D coordinates, of the points to be measured on the surface based on the laser tracker.

[0009] Therefore, the measurement system according to the invention has a measurement auxiliary device for scanning the points to be measured on the surface, which is in particular a laser scanner.

[0010] The measurement aid device has an inertial measurement unit (IMU) for determining the motion data of the measurement aid device, a reflector, and a plurality of measurement aid marks, wherein the plurality of measurement aid marks are arranged in a pattern on the measurement aid device with a certain mutual positional relationship, so that the position of the measurement aid device can be determined by the measurement system with the aid of the reflector and the orientation of the measurement aid device can be determined with the aid of the measurement aid marks or with the aid of the pattern.

[0011] In addition, the measurement system has a ranging module, a radiation module for emitting detection radiation in a variable direction, and a measurement auxiliary detection unit that can be aligned in direction, can communicate with measurement auxiliary devices, and has a detection field of view.

[0012] Here, the measurement-aided detection unit is configured to detect and track the measurement-aid device based on the detection radiation reflected by the reflector, detect the measurement-aid mark, and determine the coordinates of the surface to be measured based on the detection and tracking of the measurement-aid device, the detection of the measurement-aid mark, the distance from the measurement-aid device determined by the ranging module, and the measurement-aid device scanning the surface to be measured point.

[0013] Here, the measurement-aided detection unit is also configured to determine the coordinates of the points to be measured on the surface based on the motion data of the measurement-aided device determined by the IMU.

[0014] Furthermore, the measurement system is configured to align the measurement-aid detection unit based on motion data of the measurement-aid device determined by the IMU, so that the reflector is within the detection field of view.

[0015] The measurement aid can be, for example, a laser scanner that non-contactly scans the point to be measured on a surface using detection radiation. Based on the principle of triangulation, the laser scanner can, for example, measure the distance between the measurement aid and the point to be measured on the surface. The measurement aid can also be a white light scanner that measures the distance between the measurement aid and the point to be measured on the surface. Alternatively, the measurement aid can be a non-scanning measurement aid for non-contact measurement of the distance between the measurement aid and the point to be measured on the surface.

[0016] The measurement aid can also be a tactile scanning measurement aid, wherein at least a portion of the measurement aid is brought into contact with the surface point to be measured in order to perform the measurement. By bringing it into contact, the coordinates of the point to be measured can be determined.

[0017] An inertial measurement unit (IMU) is designed to determine motion data as a measurement aid moves, enabling a three-dimensional description of the measurement aid's motion. This motion data may, for example, relate to the measurement aid's position and / or its spatial orientation. Typically, an IMU has multiple accelerometers and yaw rate sensors for this purpose. Based on this motion data, the orientation of the measurement aid can be determined, for example, in up to three degrees of freedom.

[0018] The reflector can be a back reflector. This reflector, particularly a back reflector, is designed to reflect the detection radiation incident upon it back towards the radiation source. The detection radiation reflected by the reflector allows a measurement-aided detection unit, such as a laser tracker, to determine the position of the measurement-aided device.

[0019] For example, the reflector can be illuminated by laser radiation from a laser tracker, which is then reflected back to the laser tracker. Based on the detection of the reflected laser radiation, the laser tracker or measurement system can determine the precise angle at which the reflector is illuminated. The distance to the reflector used by the laser tracker or ranging module can also be determined based on the laser radiation reflected by the reflector. Based on the angular information involving the emitted laser radiation and the determined distance to the reflector, the laser tracker or measurement auxiliary detection unit can determine the position of the reflector and, consequently, the measurement auxiliary device.

[0020] In particular, the visual measurement aid marks are arranged in a prescribed mutual spatial relationship to form a specific pattern, which is used to enable the orientation of the measurement aid device to be determined by a measurement aid detection unit, such as a laser tracker.

[0021] The measurement aid markers can be, for example, light spots. These light spots can be generated, for example, by a light source at each point or by means of the reflection of light set for this purpose at each point.

[0022] Light from a single source can also be guided to various points via a light guide.

[0023] This light spot then generates a direction-specific pattern, which can be used by the measurement-aid detection unit to determine the orientation of the measurement-aid device. For example, this direction-specific pattern can be a light spot pattern.

[0024] To determine the orientation of the measurement aid, a spot pattern can be projected or imaged onto a plane for evaluation. The determination of the measurement aid's orientation is based on the fact that the pattern from the spot projection changes in an orientation-specific manner depending on that orientation. For example, when the measurement aid rotates about an axis, the spot projections of two spots approach or move away from each other; this axis is transverse to a connecting axis that connects the two spots and places them simultaneously in a plane parallel to the projection plane.

[0025] Therefore, the measurement-aided detection unit can determine the position of the measurement-aided device with the help of a reflector and determine the orientation of the measurement-aided device with the help of measurement-aided markings.

[0026] The ranging module is designed to measure the distance to a measuring aid using ranging radiation. This ranging module can be laser-based and designed to determine the distance based on time-of-transit measurement or interferometry principles. Typically, the ranging radiation is aligned with a reflector and at least partially reflected back to the ranging module. The ranging module is designed to determine the distance to the reflector or measuring aid based on this.

[0027] The radiation module is designed to emit detection radiation in a variable direction. This detection radiation can be laser radiation. The radiation module can be designed to emit detection radiation simultaneously in multiple directions within a defined angular range. The measurement system is therefore configured so that when the detection radiation strikes a reflector, it is reflected back to the measurement auxiliary detection unit. The measurement auxiliary detection unit is then designed to detect the reflected detection radiation and, based on this, detect and track the measurement auxiliary device. Tracking here involves the continuous alignment or tracking of the detection field of view, ensuring that the reflector is within or remains within the detection field of view.

[0028] Therefore, the detection and tracking of the measurement auxiliary device is based on the detection of the detection radiation reflected by the reflector.

[0029] Reflectors, especially backreflectors, typically have a so-called effective angle of incidence range within which incident radiation is reflected, particularly backreflected. Radiation incident at angles outside the effective angle of incidence range for reflection is not reflected as expected or is not reflected at all, especially not backreflected. For example, typical backreflectors are designed for perpendicular radiation incident, but here they also backreflect incident radiation at + / - 45–60 degrees relative to the vertical plane. In other words, reflectors also have a so-called (effective) "field of view".

[0030] Therefore, if the reflector is located in the field of view of the measurement auxiliary detection unit and there is a so-called (effective) direct line of sight between the radiation module, the measurement auxiliary detection unit and the reflector, the measurement auxiliary device can be detected and tracked. That is, here, the radiation module, the measurement auxiliary detection unit and the reflector are arranged and aligned relative to each other so that the detection radiation reflected by the reflector of the radiation module can be detected.

[0031] The measurement-aided detection unit is also configured to detect the measurement-aided marker. For example, the measurement-aided detection unit is designed to detect and continuously evaluate the pattern formed by the measurement-aided marker. Then, based on the evaluation, the orientation of the measurement-aided device can be determined.

[0032] Furthermore, the measurement-aided detection unit is configured to determine the position of the measurement aid device based on the distance measured by the ranging module and the angular information relating to the direction of the emitted ranging radiation determined by the measurement system, and to determine the orientation of the measurement aid device based on the detection of the measurement aid marker. Based on the position and orientation of the measurement aid device and the distance from the measured point on the surface determined by the measurement aid device, the coordinates of that point can be determined by the measurement-aided detection unit.

[0033] According to the present invention, the measurement-aided detection unit is also configured to determine the coordinates of the point to be measured based on motion data of the measurement-aided device determined by the IMU. Here, the motion data may be related to the position and / or orientation of the measurement-aided device. Therefore, the measurement system according to the present invention is designed to use motion data determined by the IMU to determine the coordinates. Thus, due to a certain degree of data redundancy, the measurement system can be used flexibly and efficiently.

[0034] The measurement system according to the invention is also designed to use motion data determined by the IMU for particularly continuous alignment of the measurement-aided detection unit, such that the reflector is located within the detection field of view. This allows for efficient use of the measurement system because the reflector can always be kept within the detection field of view and can therefore be detected once a direct line of sight exists between the radiation module, the measurement-aided detection unit, and the reflector. In this case, a direct line of sight means that the radiation module, the measurement-aided detection unit, and the reflector are arranged and aligned relative to each other such that the detection radiation reflected by the reflector from the radiation module (as described above) can be detected.

[0035] According to an advantageous embodiment of the measurement system, the system is configured such that if the reflector is within the detection field of view and there is a direct line of sight between the radiation module, the measurement auxiliary detection unit, and the reflector, the measurement auxiliary device can be detected and tracked at least based on the detection radiation reflected by the reflector; and if the reflector is outside the detection field of view or there is no direct line of sight between the radiation module, the measurement auxiliary detection unit, and the reflector, the measurement auxiliary device can be detected and tracked based on the motion data of the measurement auxiliary device determined by the IMU.

[0036] The latter may involve situations where, for example, the line of sight between the reflector and the measurement-aided detection unit is interrupted by an object and / or the reflector is not in the detection field of view.

[0037] This allows for flexible and largely uninterrupted use of the measurement system, as the measurement auxiliary device can be detected and tracked even when there is no direct line of sight between the reflector, radiation module, and measurement auxiliary detection unit, thus allowing the coordinates of the point to be measured to be determined.

[0038] According to an advantageous embodiment of the measurement system, the reflector is formed by a plurality of reflectors, and the plurality of reflectors are arranged on the outer region of the measurement aid and dispersed thereon in a specific relative positional relationship.

[0039] Here, the measurement system is configured such that if, after a first state in which one of the plurality of reflectors is within the detection field of view and there is a direct line of sight between the radiation module, the measurement auxiliary detection unit, and one of the plurality of reflectors, the plurality of reflectors are outside the detection field of view or there is no direct line of sight between the radiation module, the measurement auxiliary detection unit, and one of the plurality of reflectors, the measurement auxiliary detection unit is aligned based on the motion data of the measurement auxiliary device determined by the IMU, such that the time period until one of the plurality of reflectors is within the detection field of view and there is a direct line of sight between the radiation module, the measurement auxiliary detection unit, and one of the plurality of reflectors is minimized or minimized.

[0040] The state following the first state, referred to below as the interrupted state, can be, for example, a state in which none of the multiple reflectors have a direct line of sight to the radiation module and the measurement auxiliary detection unit and / or in which none of the multiple reflectors are in the detection field of view.

[0041] If such an interruption state follows the first state, the measurement system can be configured to continuously align the measurement-aided detection unit with the aid of motion data, such that one of the multiple reflectors is again within the detection field of view and / or has a direct line of sight to the radiation module and the measurement-aided detection unit within the shortest possible time period.

[0042] To this end, the measurement system is configured, for example, to determine a prediction of the future position and orientation of the measurement aid based on the motion data of the IMU, particularly the time curve of the motion data, wherein this prediction is automatically provided to the measurement aid detection unit. The measurement aid detection unit is also configured to automatically align the field of view with the predicted orientation in the event of an interruption.

[0043] For example, the measurement-assisted detection unit also has an automatic target search function, which is configured to automatically search for targets around the initial orientation of the detection field of view, wherein the prediction includes, for example, a time estimate of when the measurement-assisted device will be in a future position and orientation, and the target search function is automatically triggered based on the time estimate.

[0044] According to one embodiment of the measurement system, the measurement aid marker is designed to emit and / or reflect light.

[0045] For example, measurement aid markers can be light spots generated using light-emitting diode (LED) technology. Measurement aid markers can also be reflectors designed to reflect radiation, so that reflected radiation from the measurement aid detection unit can be detected and evaluated as a pattern.

[0046] The use of LED technology allows for variable adjustment of the light spot pattern, for example, by adjusting the light spot intensity.

[0047] According to one embodiment of the measurement system, the measurement auxiliary detection unit has a detector with a radiation-sensitive sensor. Here, the measurement auxiliary detection unit is configured to detect and track the measurement auxiliary device using the radiation-sensitive sensor and also detect the measurement auxiliary marker.

[0048] By using the same radiation-sensitive sensor for the detection and tracking of measurement aids and the detection of measurement aid markers, the measurement system can be implemented in a simple and compact configuration, thereby providing efficient measurement.

[0049] According to an advantageous embodiment of the measurement system, the measurement auxiliary detection unit is configured to alternatively determine the position and orientation of the measurement auxiliary device not only by means of the motion data of the measurement auxiliary device determined by the IMU, but also by means of a combination of means of a reflector, means of a measurement auxiliary marker and means of the motion data of the measurement auxiliary device determined by the IMU.

[0050] For example, using a combination to determine the position and orientation of a measuring aid may mean that the position and orientation of the measuring aid can be determined by means of a reflector and by means of measuring aid markers.

[0051] For example, determining the position and orientation of a measurement aid by means of combination may mean that the position and orientation of the measurement aid can be determined by means of a reflector and by means of motion data of the measurement aid determined by the IMU.

[0052] For example, determining the position and orientation of a measurement aid by means of combination may mean that the position and orientation of the measurement aid can be determined by means of measurement aid markers and by means of motion data of the measurement aid determined by the IMU.

[0053] This combinability allows for the flexible determination of the location and orientation of measurement aids using redundant data. This also enables more efficient and less disruptive measurements.

[0054] According to one embodiment of the measurement system, the measurement-aided detection unit is configured to determine the orientation and position of the measurement-aided device based on detection criteria using motion data of the measurement-aided device determined by the IMU, or using a combination of motion data of the measurement-aided device determined by the IMU, using a reflector, using a measurement-aided marker, and using motion data of the measurement-aided device determined by the IMU.

[0055] According to one embodiment of the measurement system, the detection criterion involves at least one of the following states: the measurement aid can be fully detected by means of a reflector and a measurement aid mark; the measurement aid can be detected at least partially by means of a reflector and a measurement aid mark; the measurement aid can be detected at least partially by means of a reflector or a measurement aid mark; there is no direct line of sight between the reflector and the measurement aid detection unit, and the line of sight between the measurement aid mark and the measurement aid detection unit is interrupted (the measurement aid mark cannot be seen by the measurement aid detection unit).

[0056] This allows the position and orientation of the measurement aids to be determined as appropriate, depending on the circumstances. It also allows for flexible use of the measurement system, for example, in situations where there is no direct connection to the reflector and / or the measurement aids are obstructed, or when the reflector and / or the measurement aids are outside the detection field of view.

[0057] According to one embodiment of the measurement system, the measurement auxiliary detection unit is configured to determine the position and / or orientation of the measurement auxiliary device at a first moment by means of a reflector and / or measurement auxiliary markers, and to determine the position and / or orientation of the measurement auxiliary device at a second moment by means of motion data determined by the IMU, wherein at least a portion of the second moment is located in time between the first moments.

[0058] One method, based on the orientation and / or position determination using reflectors and / or measurement aids, and another method, based on the orientation and / or position determination using motion data of the measurement aids determined by the IMU, can be coordinated to determine the position and / or orientation of the measurement aids, thereby optimizing the number of measurable points per unit time. This allows for efficient measurements with high temporal resolution.

[0059] According to an advantageous embodiment of the measurement system, the measurement-aided detection unit is configured to determine the orientation of the measurement-aided device using measurement-aided markers and motion data determined by the IMU, wherein the measurement-aided detection unit is configured to determine the orientation based on measurements averaged over a first time interval for determining the orientation using measurement-aided markers and measurements averaged over a second time interval for determining the orientation using motion data determined by the IMU.

[0060] Typically, measurements are averaged to check for measurement noise based on random measurement bias and thus measurement accuracy. Because the orientation of the measurement aid can be determined using two methods, the measurements from each method can be averaged independently of averaging the measurements from the other methods, to check for measurement noise for each method. The combination of these methods, each with its own averaging method, also allows for highly accurate determination of the coordinates of the point to be measured, even when the measurement aid is manually operated.

[0061] According to one embodiment of the measurement system, the measurement-aided detection unit is also configured to continuously calibrate motion data determined by the IMU based on the position and / or orientation determined by the reflector and / or measurement-aided markers.

[0062] Typically, IMU measurements carry systematic biases. For example, the IMU sensor offset and its scaling factor must be continuously calibrated. To check for this systematic bias, the IMU can be calibrated and then recalibrated at specified time intervals. Because the position and / or orientation of the measurement aids can be determined using both IMU methods and methods involving reflectors and measurement aid markings, the position and orientation of the measurement aids determined using reflectors and measurement aid markings can be used to calibrate, particularly to continuously recalibrate, the IMU, for example, to continuously calibrate the IMU sensor offset and associated scaling factor. This allows for flexible use of the measurement system.

[0063] The IMU and calibration data regarding the position and / or orientation of the measurement aid, i.e., so-called absolute data, are combined, for example, using a state estimation filter such as a Kalman filter. Using this filter, a statistical dynamic model is employed to estimate the 6DOF pose and intrinsic parameters of the measurement aid, such as IMU offset. For each sensor value, the model is updated accordingly, taking into account not only the sensor value and its uncertainties but also estimates of the measurement aid's dynamics. This allows for the fusion of various types of sensors, potentially with different measurement rates, while fully utilizing the strengths of each sensor. The IMU remains continuously calibrated, and high-frequency noise in the measurement system is attenuated and replaced with less noisy but more drift-prone IMU data.

[0064] If the IMU noise is low enough, random noise from the absolute system (e.g., caused by air turbulence) can be almost completely eliminated, thus providing a signal primarily limited by the systematic errors of the absolute system. In many cases, this signal can be used during motion without further averaging, achieving an accuracy similar to that of a static measurement in a system without an IMU, including averaging. This allows for, for example, faster tactile measurements because the measurement aid does not need to remain stationary for a longer period (e.g., 3 seconds) during the measurement. This long averaging time is primarily attributable to air turbulence fluctuating on a relatively “slow” timescale. Therefore, tracking accuracy at least as high as that of a static measurement aid can be achieved using a scanning measurement aid.

[0065] By combining absolute measurements, for example, performed at 100 Hz, with IMU data obtained, for example, at 1 kHz, it is possible to track motion dynamically an order of magnitude faster without loss of absolute accuracy. The IMU thus allows for determination of the absolute 6DOF system at lower frame rates.

[0066] If a simple sensor fusion filter is used, for example, to estimate the orientation of the measurement aid from only the IMU and the measurement aid markers without modification, the same type of state estimation filtering algorithm as described above can be employed. Alternatively, a simplified algorithm can be used, such as a low-pass filter for absolute angles and a matched high-pass filter for IMU angles, thereby resulting in a flat frequency response of the final signal and maintaining the absolute accuracy of the marker-based system, while benefiting from reduced noise and a higher sampling rate of the IMU data.

[0067] For real-time applications such as obstacle avoidance where rapid response time is critical, such as state estimation filtering performed only forward, i.e. in causal mode (i.e., using only information from earlier measurements, without information from future measurements).

[0068] For applications requiring high precision, such as interpolation or noise suppression, filters are adapted to operate in a non-causal manner, using future information to estimate the state at each point. This can be achieved, for example, through so-called Kalman filtering smoothing, where the filter adds a backward pass through the data set to propagate state information in the opposite direction.

[0069] Another potential advantage is that approximate geographical locations can be considered for absolute data to compensate for the Earth's rotation.

[0070] According to one embodiment of the measurement system, the measurement system is configured to identify the approach of a measurement aid device to an obstacle having a certain position and shape based on motion data determined by means of an IMU.

[0071] For example, the measurement system can have data on the location and shape of an obstacle located on the surface to be measured. This data can be used as a reference to the position of a measurement aid, whereby the movement of the measurement aid relative to the obstacle can be tracked using motion data determined by an IMU. Based on this tracking, it is possible to identify when the measurement aid is approaching an obstacle. Based on this proximity detection, the user of the measurement system can be warned of a potential collision. This allows for the safe and efficient use of the measurement system.

[0072] According to one embodiment of the measurement system, the measurement system is configured to trigger proximity detection if there is no direct line of sight between the reflector and the measurement-aided detection unit, particularly within a certain time period.

[0073] Thus, collision measurement aids can also be prevented in situations where they are not used directly during measurement.

[0074] According to one embodiment of the measurement system, the measurement system is configured to signal to the user of the measurement aid device, via optical feedback and / or acoustic feedback and / or tactile feedback, that proximity has been identified.

[0075] According to one embodiment of the measurement system, the measurement aid is a laser scanner, and the radiation module, ranging module, and measurement aid detection unit are part of a laser tracker. Attached Figure Description

[0076] The measurement system of the present invention will be described in detail below with reference to specific embodiments illustrated in the figures. Other advantages of the present invention will also be introduced here. Specifically:

[0077] Figure 1 An embodiment of a measurement system for determining the coordinates of a point to be measured on a surface is shown.

[0078] Figure 2 One embodiment of a manually operable measurement aid for non-contact scanning of a surface at a point to be measured is shown.

[0079] Figure 3 One embodiment of a measurement aid device for automatically guiding the measurement point on a non-contact scanning surface is shown.

[0080] Figure 4 One embodiment of a manually operable measurement aid for scanning a surface to be measured in a tactile manner is shown. Detailed Implementation

[0081] Figure 1 A measurement system 1 according to a first embodiment of the present invention is shown. The measurement system includes a measurement auxiliary device 2. This device is designed for manual operation and non-contact scanning of a surface to be measured. The measurement system also includes a distance measuring module 6 designed to measure the distance to the measurement auxiliary device 2. Furthermore, the measurement system 1 includes a radiation module 7 designed to emit detection radiation with a variable direction. Figure 1 The measurement system shown has an oriented measurement auxiliary detection unit 8.

[0082] Figure 1 The measurement system 1 shown illustrates a laser tracker 13 and a measurement aid implemented in the form of a laser scanner.

[0083] Figure 1 and Figure 2The measurement aid 2 shown has an inertial measurement unit (IMU) 3 (not shown) integrated within it, which determines the motion data of the measurement aid. Furthermore, the measurement aid has multiple reflectors 4, 4', 4" forming reflectors and multiple measurement aid marks 5, 5', 5" forming reflectors. The measurement aid has a handle 9, by which it can be manually operated.

[0084] Figure 3 The measurement aid 2' shown is designed for automatic guidance. For this purpose, it is attached to the automatic guidance unit, such as component 10 of a robot.

[0085] Figure 4 A measurement aid 2” is shown, which is designed to be manually manipulated and scanned tactilely on a surface to be measured. For this purpose, the measurement aid has a tactile sensor attachment 11 with a ball 12, which contacts the point to be measured. The measurement aid 2” has a reflector 4”' and multiple measurement aid marks 5”'.

[0086] Obviously, the accompanying drawings are only schematic representations of possible implementations.

Claims

1. A measurement system (1) for determining the coordinates of a test point on a surface based on a laser tracker, the measurement system (1) having: o A measurement auxiliary device (2, 2', 2'') for scanning the points to be measured on the surface, the measurement auxiliary device (2, 2', 2'') having: o An inertial measurement unit (IMU) used to determine the motion data of the measurement auxiliary device; o Reflector (4); and o Multiple measurement auxiliary markers (5, 5', 5''). in, The plurality of measurement auxiliary marks are arranged in a pattern with a certain mutual positional relationship on the measurement auxiliary device, so that the measurement system can determine the position of the measurement auxiliary device with the aid of the reflector and determine the orientation of the measurement auxiliary device with the aid of the measurement auxiliary marks. o Distance measuring module (6) o Radiation module (7) for transmitting detection radiation in a variable direction. o A measurement-aided detection unit (8) capable of alignment, the measurement-aided detection unit (8) being communicatively connected to the measurement-aid device and having a detection field of view, wherein the measurement-aided detection unit is configured to: o Detect and track the measurement aid based on the detection radiation reflected by the reflector; o Detect the measurement auxiliary marker; and The coordinates of the points to be measured on the surface are determined based on the following conditions: Detection and tracking of the aforementioned measurement auxiliary device; Detection of the measurement auxiliary markers; The distance to the measuring aid determined by the ranging module; and The measurement auxiliary device is used to scan the points to be measured on the surface. Its features are, The measurement-aided detection unit (8) is further configured to determine the coordinates of the point to be measured on the surface based on the motion data of the measurement-aided device determined by the IMU, and o The measurement system (1) is configured to align the measurement auxiliary detection unit with the motion data of the measurement auxiliary device determined by the IMU, such that the reflector is within the detection field of view.

2. The measurement system according to claim 1, characterized in that, The measurement system is configured such that If the reflector (4) is within the detection field of view and there is a direct line of sight between the radiation module (7), the measurement auxiliary detection unit (8), and the reflector, then the measurement auxiliary device (2, 2', 2'') can be detected and tracked at least based on the detection radiation reflected by the reflector. o If the reflector is outside the detection field of view or there is no direct connection between the radiation module, the measurement auxiliary detection unit and the reflector, the measurement auxiliary device can be detected and tracked based on the motion data of the measurement auxiliary device determined by the IMU (3).

3. The measurement system according to claim 2, wherein, The reflector (4) is composed of multiple reflectors (4, 4', 4'') and the multiple reflectors are arranged on the outer region of the measuring auxiliary device (2, 2', 2'') and distributed thereon in a certain positional relationship. The measurement system is characterized in that, if, after a first state in which one of the plurality of reflectors (4, 4', 4'') is within the detection field of view and there is a direct line of sight between the radiation module (7), the measurement auxiliary detection unit (8), and one of the plurality of reflectors, the state in which one of the plurality of reflectors is outside the detection field of view or there is no direct line of sight between the radiation module, the measurement auxiliary detection unit, and one of the plurality of reflectors, then the measurement auxiliary device is aligned based on motion data of the measurement auxiliary device determined by the IMU (3), such that the time period until one of the plurality of reflectors is within the detection field of view and there is a direct line of sight between the radiation module, the measurement auxiliary detection unit, and one of the plurality of reflectors is minimized.

4. The measurement system according to any one of claims 1 to 3, characterized in that, The measurement aid markers (5, 5', 5'') are designed to emit and / or reflect light.

5. The measurement system according to claim 1, wherein, The measurement-aided detection unit (8) has a detector with a radiation-sensitive sensor, characterized in that the measurement-aided detection unit is configured to utilize the radiation-sensitive sensor. o Detect and track the measurement aids (2, 2', 2''), and o Detect the measurement auxiliary markers (5, 5', 5'').

6. The measurement system according to claim 1, characterized in that, The measurement-aided detection unit (8) is configured to alternately determine the position and orientation of the measurement-aided device, thereby not only o Using the motion data of the measurement aids (2, 2', 2'') determined by the IMU (3), and also o Using a combination of the following items: o Using the reflector (4); o Using the aforementioned measurement aid markers (5, 5', 5''); and o Using motion data from the measurement aid determined by the IMU.

7. The measurement system according to claim 1, characterized in that, The measurement-aided detection unit (8) is configured to determine the orientation and position of the measurement-aided devices (2, 2', 2'') based on detection standards. o Using the motion data of the measurement aid determined by the IMU (3), or o Using a combination of the following items: o Using the reflector (4); o Using the aforementioned measurement auxiliary markers (5, 5', 5''), and o Using motion data from the measurement aid determined by the IMU.

8. The measurement system according to claim 7, characterized in that, The testing standard involves at least one of the following states: o The measuring auxiliary devices (2, 2', 2'') can be detected entirely by means of the reflector (4) and the measuring auxiliary marks (5, 5', 5''). The measurement aid device can be detected at least partially by means of the reflector and the measurement aid marker. The measurement aid device can be detected at least partially by means of the reflector or the measurement aid marker, and There is no direct line of sight between the reflector and the measurement-aided detection unit, and the line of sight between the measurement-aided mark and the measurement-aided detection unit is interrupted.

9. The measurement system according to claim 1, characterized in that, The measurement-aided detection unit (8) is configured to determine the position and / or orientation of the measurement-aided devices (2, 2', 2''), for which... o At the first moment, with the aid of the reflector (4) and / or the measurement auxiliary marks (5, 5', 5''), and o At a second time point, motion data determined by the IMU (3) is used, wherein at least a portion of the second time point is located between the first time points in time.

10. The measurement system according to claim 1, wherein, The measurement-assisted detection unit (8) is configured to determine the orientation of the measurement-assisted device (2, 2', 2'') using the measurement-assisted markers (5, 5', 5'') and motion data determined by the IMU (3). The characteristic is that the measurement-assisted detection unit (8) is configured to determine the orientation based on the following conditions: o The averaged measurement over the first time interval is used to determine the orientation with the aid of the measurement auxiliary marker, and The averaged measurement over the second time interval is used to determine the orientation using motion data determined by the IMU.

11. The measurement system according to claim 1, characterized in that, The measurement-assisted detection unit (8) is also configured to continuously calibrate motion data determined by the IMU (3) based on the position and orientation determined by the reflector (4) and the measurement-assisted markers (5, 5', 5'').

12. The measurement system according to claim 1, characterized in that, The measurement system is configured to identify the approach of the measurement aid (2, 2', 2'') to an obstacle with a certain position and shape based on motion data determined by the IMU (3).

13. The measurement system according to claim 12, characterized in that, The measurement system is configured to automatically trigger proximity detection if there is no direct line of sight between the reflector (4), the radiation module and the measurement auxiliary detection unit (8).

14. The measurement system according to claim 13, characterized in that, The measurement system is configured to signal the user of the measurement aid (2, 2', 2'') to indicate proximity via optical and / or acoustic and / or tactile feedback.

15. The measurement system according to claim 1, characterized in that, o The measurement auxiliary device (2, 2', 2'') is a laser scanner, and o The radiation module, the ranging module and the measurement auxiliary detection unit (8) are part of the laser tracker (13).

16. The measurement system according to claim 13, characterized in that, The measurement system is configured to automatically trigger the recognition of proximity if there is no direct line of sight between the reflector (4), the radiation module and the measurement auxiliary detection unit (8) within a certain period of time.

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