GEODETIC INSTRUMENT COMPRISING A BASE AND A GEODETIC SURVEYING AND/OR PROJECTION MODULE

A geodetic instrument with a base module and a surveying or projection module. A processor for control of the instrument is situated in the base module. The surveying or projection module is rotatable about two axes by a drive unit of the base. The instrument comprises a mechanical interface connecting the surveying or projection module to the base module and an optical or electrical contact interface between the base module and the geodetic surveying or projection module. The interfaces are designed such that the surveying or projection module is mountable to the base module and dismountable from the base module by a user, whereby the geodetic instrument is designed for mounting of various surveying or projection modules of different geodetic type and execution of accordingly different geodetic surveying or projection functions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to European Patent Application No. 20153248.8, filed on Jan. 22, 2020. The foregoing patent application is herein incorporated by reference.

FIELD OF INVENTION

The present invention relates to a geodetic surveying and/or projection instrument, in particular for construction works such as layout or stakeout tasks (“design to reality”) or as-built data capture (“reality to design”), a geodetic instrument base and a geodetic surveying and/or projection module.

BACKGROUND

Geodetic instruments for surveying or projection e.g. of point coordinates are known in the art. Such surveying appliances for tracking or marking and surveying spatial points on surfaces of a structure or object are particularly used for measuring of a surrounding or workpiece, in particular large entities such as fuselages, or construction or inspection of buildings, e.g. in course of BIM (Building Information Model) to Field-assignments or laying out building elements such as MEP (Mechanical Electrical Plumbing) installation, walls, anchor points etc. The distance and angle from a such measuring device to one or more target points to be surveyed can be recorded as spatial standard data. On the other hand, planned position data, e.g. based on a digital building plan or CAD-data, can be projected in a position true manner on an object's surface by a laser beam for layout or stake out purposes. Such instruments are used for traditional geodesy (land surveying) or for geodetic measuring in the industry (e.g. 3D-coordinate acquisition of workpieces for quality control) as well as for accurate construction of buildings like streets, tunnels or houses and for interior construction or assembly tasks, e.g. using templating, by designers like architects, kitchen makers, glaziers, tilers or staircase builders, e.g. for as-built data capture. It is emphasized that, in the present application, the terms “geodesy” and “geodetic” are not limited to the scientific discipline that deals with the measurement and representation of the surface of the earth and the seafloor, but relate in a broad sense to measuring, surveying and position determining or projection of object points in order to acquire digital object coordinates or mark digital object coordinates in space.

Known geodetic instruments of the generic type such as construction surveying appliances typically comprise a base, an upper part mounted so as to be able to rotate about an axis of rotation on the base, and a sighting unit, mounted so as to be able to swivel about a swivel axis, with a laser source, which is designed to emit a laser beam, and an imaging detector, for example equipped with an orientation indicating functionality for indicating an orientation of the sighting unit with respect to a spatial point as a sighting point, and also with a distance determining detector for providing a distance measuring functionality. By way of example, the orientation indicating functionality may be a reticle in the viewfinder or a camera as imaging detector.

Modern, automated construction surveying appliances furthermore comprise rotary drives, which make the upper part and/or the sighting unit drivable in a motorized manner, goniometers and, if appropriate, inclination sensors for determining the spatial orientation of the sighting unit, and also an evaluation and control unit, which is connected to the laser source, the distance determining detector and also the goniometers and, if appropriate, inclination sensors.

In this case, the evaluation and control unit is equipped, by way of example, with a display having input means for inputting control commands from a user on the display (e.g. touchscreen) or what is known as a joystick that is directable, for the purpose of altering the orientation of the sighting unit by directing the joystick, and for presenting an image from the imaging detector or the camera on the display, wherein the orientation of the sighting unit can be indicated by means of the orientation indicating functionality on the display, e.g. by means of overlaying. Functionalities are known in which the input means on the display are in the form of arrows, the marking and touching of which enable a user to alter the orientation of the sighting unit in a horizontal or vertical direction.

On the other hand, projection of visible or invisible points or lines is used for providing positional reference points or lines serving as a reference for either the human eye or for electronic systems and also allowing automatic positioning or machine guidance. Here, the reference lines are usually created by widening a laser beam, which is possible for straight lines in particular, or else by rotating projection of a laser point.

An example of geodetic instruments suitable for this are rotating lasers or line or point lasers, which serve to fix a plane using a visible or invisible laser beam and have been in use for a number of years now, for example in the building trade or in industry. They are a valuable aid for marking construction lines on horizontal, vertical or else defined angled planes. However, previous rotating lasers are disadvantageous in that they are only able to create those projection planes which contain the initial point of the laser beam. Thus, in order to project spatial points along a line in a predefined horizontal plane, the light emission point of a conventional rotating laser must be positioned precisely in this plane and the laser module must be adjusted precisely to the horizontal light emission (and the rotation axis must be aligned precisely vertical). Thus, the work region for using a rotating laser for marking a horizontal plane is restricted to the adjustment region for the height of a base on which the rotating laser is mounted. Projecting a laser beam rotating about a vertical axis by means of a conventional rotating laser in a non-horizontal (e.g. directed obliquely upward) direction leads to spatial points situated closer being projected to a lower height than spatial points situated further away.

DE 44 43 413 discloses a method and a device for both measuring and marking on distanced lines or areas. One or more relevant spatial points are measured in respect of in each case two spatial angles and the distance in relation to a reference point using a laser-distance measuring unit, mounted in a cardan-type mount. The laser-distance measuring unit is pivotable about two mutually perpendicular axes which are equipped with goniometers. In accordance with one embodiment described in these documents, spatial points to be measured are targeted manually, marking points are calculated from the measurement data based on a predetermined relative relationship between measuring and marking, which marking points are then targeted independently by the measuring and marking device.

As another example, EP 2 053 353 discloses a reference line-projecting unit with an electro-optical distance measuring unit. In accordance with the teaching of this application document, an optical reference beam, in particular a laser beam, is routed along a defined reference path. By integrating a distance measuring unit, the system disclosed in EP 2 053 353 also enables a control of the projection on the basis of an established surface topography.

DE 196 48 626 discloses a method and an apparatus for area surveying with a laser rangefinder having a laser transmitter and a laser receiver. The laser rangefinder is mounted on a stand. The apparatus furthermore comprises a tilting and rotating device for orientation and direction measurement, a telescopic sight and also an electronic evaluation unit for angle data capture, distance data capture and data transfer to a computer. For surveying a space, the appliance is positioned at a central location in the space. However, often it is not possible that all spatial and/or area corner points to be detected can be sighted and impinged upon by the laser beam from only one location and multiple stationings are necessary to cover all points to be surveyed whereby it is cumbersome and time-consuming to move and position the apparatus.

As can be seen, a large number of technical arrangements and methods are known for measuring and/or marking spatial points in the course of construction or development of buildings. Also, in order to fulfil complex surveying tasks, in particular in a free terrain, geodetic total stations or theodolites, as known in the generic prior art, have been used for very many years. Such devices are, in principle, technically also suitable for fulfilling a plumb point finding functionality, for example during interior finishing of a building. However, they are technically relatively complex and costly devices.

In addition, it is cumbersome and costly to have to provide many different geodetic instruments for different surveying or projection tasks to be done. As another disadvantage, such bulky instruments must be carried around when measuring, even when measuring only roughly or supplemental. Above that, with large instruments of the state of the art, some locations such as contorted room edges or very near to a surface (e.g. direct beneath a ceiling) are difficult to reach if not impossible to reach at all.

BRIEF DESCRIPTION

It is therefore an object of some aspects of the invention to provide an improved geodetic instrument.

It is a further object of some aspects the invention to provide an improved geodetic instrument which facilitates different geodetic surveying and/or projection tasks.

This object is achieved by the realization of the characterizing features of the independent claims. Features that develop the invention in an alternative or advantageous manner can be gathered from the dependent patent claims and also the description including the descriptions of figures. All embodiments of the invention that are illustrated or disclosed in some other way in this document can be combined with one another, unless expressly stated otherwise.

Some aspects of the invention relate to a geodetic instrument, for example for construction works, with a base module and a surveying and/or projection module. The geodetic instrument comprises a mechanical interface connecting the surveying and/or projection module to the base module and an optical and/or electrical contact interface adapted for transmission of data and/or energy between both modules. The surveying and/or projection module comprises at least one sensor, e.g. an electronic distance sensor, and/or projector, e.g. a point laser, for acquisition and/or projection of object data.

The base module comprises an electrical power unit for powering the geodetic instrument, a first processor, powered by the electrical power unit, for processing of geodetic data and control of the geodetic instrument. Further, the base module comprises at least one drive, powered by the electrical power unit, adapted for driving the geodetic surveying and/or projection module about two rotational axes (by rotation of the module relative to the base and/or rotation of the base and therewith the module), in particular a horizontal and a vertical axis and at least one angle encoder for measuring the rotational position of the surveying and/or projection module with respect to the two rotational axes, for example an angle sensor for a respective axis, each.

Said interfaces are designed such that the surveying and/or projection module is mountable to the base and dismountable from the base module by the user. Additionally, the geodetic instrument is designed for mounting of various surveying and/or projection modules of different geodetic type to the base module and execution of accordingly different geodetic surveying and/or projection functions. Thus, the geodetic instrument can be used for example like a total station when equipped with one module, like a laser scanner when another module is mounted by the user and like a rotating laser with still another of the exchangeable modules—whereby a module may cover in itself more than one geodetic function—, all this with one and the same base module and without displacing the instrument, i.e. in one and the same stationing.

Optionally, the geodetic instrument is designed in such a way that all of the mountable various surveying and/or projection modules are referenced to one and the same origin of coordinates. Thus, all modules relate to the same point without any parallax or offset. No transfer or correction (e.g. no correction matrices) of coordinates are needed but a user can for instance measure with one surveying and/or projection module, exchange it with another surveying and/or projection module and acquire additional measurement data directly in the same coordinate space or project digital point data referenced to the same origin as the first measurement.

For ease of exchange, optionally the interfaces are designed such that an operable mounting of dismounted surveying and/or projection module to the base module—and analogically dismounting of mounted surveying and/or projection module—is effectable by a single manual action of the user, e.g. pushing only one knob or release button for dismounting and mounting the surveying and/or projection module just by “clicking” it to the base module. For example, mounting and dismounting can be done by only one substantially linear or rotational hand movement, either with a tool or tool-free. As a further option, and/or the mechanical and optical and/or electrical contact interfaces are designed as a joined interface (which can be seen as one interface providing mechanical connectivity as well as optical and/or electrical connectivity; hence, in the present invention, “interface” is sometimes used both for mechanical or optical and/or electrical connection means as well as for the interface as a whole and only part or counterpart of the interface).

Additionally or alternatively, the mechanical interface is designed such that a mechanically stable mounting of the surveying and/or projection module to the base module is secured by at least one of a magnet (with magnetic or ferromagnetic counterpart), one screw, one spring-loaded catch/claw, one twistable catch/claw, a bayonet fastening, one ball lock pin. Preferably, in case of fixing means such as a screw or claw, there is exactly one of it (only one anchor point) such that a user has only to manipulate one of them to mount or dismount.

As another option, the mechanical interface is designed in such a way that the mounting position of a respective surveying and/or projection module is precisely reproducible and thermally stable. That is that a respective surveying and/or projection module is placed in exactly the same way onto the base module in spite of the various mounting and dismounting procedures and thermal or temperature variation.

Optionally, the surveying and/or projection module is designed as a portable stand-alone geodetic surveying and/or projection module with a battery, a data storage and a second processor in such a way that temporarily geodetic, e.g. free-hand, surveying and/or projection with the geodetic surveying and/or projection module dismounted from the base is enabled. In other words, the surveying and/or projection module is not only functional or operative when connected to the base module but also in some limited form on its own.

Optionally, the mechanical interface comprises at least three guidance elements with equal angular spacing to each other whereby each guidance element comprises a ball or spherical calotte and a two-point support as a receiving counterpart, each two-point support being for example embodied as one prism or two cylinders. Preferably, the ball or spherical calotte and a two-point support are preloaded with respect to each other by magnetic force or by springs.

In embodiments with an electric interface, the surveying and/or projection module is optionally chargeable by the power unit through the electric interface. As another option, a battery of the surveying and/or projection module serves as an electrical power reserve for the whole instrument. That is that not only the surveying and/or projection module can be powered by the base module but also the other way round the surveying and/or projection module can power the base module.

Optionally, the base module and the surveying and/or projection module comprise a transmitter each for wireless data transmission between base and (dismounted) module. In this case, as a further option, the surveying and/or projection module can be controlled wirelessly by the base module (processor) even when dismounted from the base in remote control.

As another option, the centre of gravity of the instrument is such that the instrument can be positioned stable by the base. The base module then comprises a ground surface, e.g. a complete flat bottom surface or three or more points defining a surface. Additionally or alternatively, the base module comprises a release interface for attaching the geodetic instrument to a support structure, in particular a tripod.

Some aspects of the invention also relate to a geodetic instrument base module comprising an electrical power unit, a (first) processor, powered by the electrical power unit, for processing of geodetic data and control of the base module. The instrument base module comprises further a mechanical interface part and an optical and/or electrical contact interface part. The interfaces are designed for mounting and dismounting a surveying and/or projection module by a user (in the field). By the optical and/or electrical contact interface, data and/or energy can be transmitted between the base module and the surveying and/or projection module if mounted. The processor is further adapted for control of a respective surveying and/or projection module.

The base module further comprises a drive, powered by the electrical power unit, adapted for driving the mechanical interface and/or the base module about two rotational axes, in particular a horizontal and a vertical axis, and at least one angle encoder for measuring the respective rotational position. In other words, the base comprises a drive adapted for driving the mounted surveying and/or projection module about two rotational axes, by changing a rotational position of the base itself and/or the rotational position of the mechanical interface, and at least one angle encoder for measuring the rotational position of the mounted geodetic surveying and/or projection module with respect to the two rotational axes.

Optionally, the base module comprises a power unit part comprising the power unit and a main part and the drive comprises a first drive unit for rotation of the main part (and therewith the module if mounted) relative to the power unit part about a first, in particular vertical, axis and a second drive unit for rotation of the mechanical interface (and therewith the mounted module) relative to the main part about a second, in particular horizontal, axis. Further, a respective angle encoder is integrated in the drive unit each. Preferably, the first and the second drive unit are of identical construction or type.

As further options, the mechanical interface and the optical and/or electrical contact interface are integrated in the second drive unit and/or the power unit part is tool-free exchangeably connected to the main part.

Optionally, the mechanical interface of the base comprises a centering and a fixation and/or the base module is asymmetric with respect to a vertical axis.

Some aspects of the invention further relate to a surveying and/or projection module comprising a mechanical interface counterpart designed for connecting the surveying and/or projection module to a geodetic base module according to the invention as described above and an optical and/or electrical contact interface counterpart adapted for transmission of data and/or energy between the base and the geodetic surveying and/or projection module. Preferably, the interfaces are designed such that the surveying and/or projection module is mountable to the base module and dismountable from the base module tool-free.

Further, the surveying and/or projection module is optionally designed as a portable stand-alone geodetic surveying and/or projection module with a battery, a data storage and a (second) processor in such a way that temporarily geodetic, for example free-hand, surveying and/or projection with the geodetic surveying and/or projection module dismounted from the base is enabled.

Optionally, the module is embodied as a laser scanning head, an opto-electronic surveying head, a point or line laser projector, a camera head with at least one camera and/or a multi-photo measuring head, whereby the features can be mixed in one and the same head (e.g. a module with a camera and a pointing laser).

As another option, the surveying and/or projection module comprises a telescope and/or a panorama and/or wide angle objective, and an illumination light for illumination of the field of view of the telescope and/or the objective. In other words, the surveying and/or projection module comprises a light source for illumination of the target or object space visible by the telescope of objective. As a further option, the surveying and/or projection module comprises an automatic target recognition unit designed for tracking (locking onto) geodetic targets such as a retroreflector.

For projection functionality, the surveying and/or projection module optionally comprises a first line laser, a second line laser and a point laser, whereby the emission plane of each of the two line lasers is oriented orthogonal to each other and to emission direction of the point laser.

Hence, the present invention advantageously provides a geodetic instrument which covers different geodetic technologies with only one instrument resp. one and the same basic infrastructure and different measuring top pieces. The instrument base can be equipped with surveying and/or projection modules of various type such that there is a multi-purpose geodetic instrument available whereby quick and comfortable exchange of modules is enabled. The exchange of e.g. a TPS head with a scanner head or the other way round can be done in the field by the user preferably tool-free without moving the instrument. Thus, the operator can complete a layout and scan on a single setup and most advantageously referenced to one and the same origin of coordinates. Then, the scan data can be used by the TPS head to position itself in space.

In addition, the surveying and/or projection modules preferably are designed such that they are (limitedly) usable as stand-alone geodetic devices. Thus, the functionality of the geodetic instrument is even more enlarged. For example, quick overview or supplemental measurements or surveying, using imaging technologies with embedded cameras and/or projection at otherwise inaccessible sites is enabled.

Some aspects of the invention allow for an uncomplicated and easy adaption to different geodetic objects or geodetic tasks by the user on-site, without the need for many different costly separate “full-fledged” instruments.

The geodetic instrument according to the invention is described or explained in more detail below, purely by way of example, with reference to working examples shown schematically in the drawing. Identical elements are labelled with the same reference numerals in the figures. The described embodiments are generally not shown true to scale and they are also not to be interpreted as limiting the invention.

DETAILED DESCRIPTION

FIG. 1illustrates a first example of a geodetic instrument1according to the invention and its utilisation by a user3.

FIG. 1shows on its left side the geodetic instrument1having a base module2and a surveying and/or projection module4connected to the base2by an interface5. The geodetic instrument1is positioned on a tripod7as support structure by a release interface (not shown). In this setup, the geodetic instrument1can be used in principle as a portable geodetic device known in the art like a total station or theodolite, laser templator or laser scanner, which is positioned at a station for example for surveying or measuring purposes in indoor or outdoor construction works, if the surveying and/or projection module4is embodied as an opto-electronic surveying head, multi-photo measuring head or laser scanner head. As a further example, having a projection module4, the instrument1can be used as a point and/or line laser projector, e.g. in form of a laser level or rotary laser. Further, a projection module4can be used for position true projection of a point, line or geometric shape on an object's surface according to a construction plan or CAD-data or the like, enabling a visual marking of a nominal position such that for instance a construction work can be performed at or according to that nominal position. For example, the instrument1provides by module4a 780 nm EDM (electronic distance measuring) laser for surveying and a 532 nm laser for pointing.

Further, as also known in principle by the skilled person, the instrument1can comprise an automatic target recognition (ATR)-unit (not shown) in the geodetic module4for locking onto a geodetic target such as a surveying pole respectively for target tracking. In addition, a far field ATR is optionally present.

For whatever surveying or construction task, the user3can command or operate the geodetic instrument1by a user interface (not shown) situated at the base2. For example, a measuring of 3D coordinates of object points (single point measurement or scanning) can be started by pushing a button at the instrument or a remote control or running on a tablet/smartphone/control unit once the instrument1is stationed in a room as indicated in the figure (reference number6).

According to the invention, the surveying and/or projection module4of the geodetic instrument1is also easily dismountable, e.g. tool-freely, from the base2(indicated by arrow8) and exchangeable by another surveying and/or projection module by the user3. That is the “sensitive” main component4of instrument1can be connected to the base main component2and disconnected from it in the field conveniently by user3. Further, the geodetic instrument1is designed such that surveying and/or projection modules4of different type are supported by base module2and operable with their varying functionalities. For example, a laser scan module4for scanning an environment can be exchanged by a laser projection module for visually marking planned position or object points in the environment.

All mountable modules4thereby relate to one and the same origin of coordinates. Hence for instance, a surrounding first can be scanned by a scanning module4, then referenced or compared to a stored digital map of the surrounding, the map comprising target positions, and then these target positions can be visibly marked position-true in the surrounding by a projection module4mounted by the user3instead of the scanning module4in the meantime, based on the scan data and reference data. Thereby, due to the same coordinate origin, no parallax has to be taken into account and no computational correction of coordinates is needed.

In the example, surveying and/or projection module4is in addition not only operational in connection to the base module2, but temporarily usable as stand-alone geodetic device. As indicated in exemplaryFIG. 1, the user3can use the module4for free-hand geodetic tasks, controlling it by a human-machine-interface (HMI) at the module4(indicated by reference number9).

For example, often not all 3D coordinates of a room can be measured from a station but some points are hidden or occluded. The user3then can quickly disconnect the geodetic module4wherefore conveniently no tools are necessary, go to a position wherefrom the missing points are visible and measure these points. Measuring can be done e.g. using a measuring beam L as shown in the figure and using measuring methods such as time-of-flight, phase, wave form, photogrammetric or interferometric evaluation.

Preferably, the interface5comprises an electrical contact such that the battery of the surveying and/or projection module4can be loaded from the power unit of the base2through this electrical interface, thus providing an easy and self-reliant way of charging surveying and/or projection module4.

For referencing of free-hand measurements with dismounted surveying and/or projection module4to the same reference or coordinate system of the stationary measurements, the module4comprises for instance positional sensors such as an inertial measurement unit (IMU), gyroscope and/or inclinometer or GNSS-receivers in case of outdoor activities (not shown). Additionally or alternatively, a referencing such as registration of 3D point clouds can be effected by measuring a number of reference points from both the stationary position as well as from the free-hand position and/or by 2D- or 3D-image based path derivation using image processing techniques such as feature matching with algorithms such as SIFT—(Scale Invariant Feature Transformation), SURF—(Speeded Up Robust Features), FAST—(Features from Accelerated Segment Test), BRIEF—(Robust Independent Elementary Features) or ORB—(Oriented FAST and Rotated BRIEF).

As another example, the autonomy of the surveying and/or projection module4and its relatively small size can be used to position it at nearly every position, in particular positions which are not accessible with the relatively large or bulky geodetic device1as a whole. Thus, e.g. a level laser can be emitted from nearly everywhere in a room. For this purpose, the geodetic module4may have attaching means such as magnet or clamp (not shown) for attaching it onto a wall or ceiling or the like.

As still another example, the possibility of independent operation of the geodetic module4enables the user3to perform quick data acquisition such as a rough scanning of a room. Hence, for instance a 3D-overview of a surrounding can be gathered just by the user3holding the module4and turning around himself. When more reliability resp. more precise measurement is needed, e.g. a specific section of the surrounding determined or selected based on the rough overview surveying, the geodetic module4is then mounted to the base2—which is easily done due to the tool-free handling enabled by interface5—for improved measurement capabilities.

Improved surveying capabilities of the complete geodetic device1as a whole—compared to the geodetic module4on its own—are provided by the stable holding and automatic positioning of the geodetic module4when mounted to the base2. For precise positioning and thus measuring or projecting, the base2comprises a drive (not shown inFIG. 1), powered by an electrical power unit (not shown) of the base module2, for driving the surveying and/or projection module4about a first axis H and a second axis V. The respective actual rotational position about each axis H, V is determined with respective angle encoder (not shown).

In addition, the power unit of the base2possesses a relatively large capacity, allowing for power intensive computations with a processor built into the base2, power intensive surveying operations such as measuring points in the far field with a measuring beam and long operating duration. Compared with, the geodetic module4when used as a temporarily stand-alone device is of limited operational and computational power.

For example, data intensive measurements (e.g. a laser scan) in the autonomous, off-station modus of the surveying and/or projection module4are just stored on an internal data storage of the module4without any further data evaluation or processing. Then, after attaching the module4to the base2, the stored data is transferred to the base module2and the computational power of the base2is used to process and evaluate the measurement data and e.g. to form a graphic representation or interpretation, displaying it on a display of the instrument1(which may also be a portable display such as a tablet or smartphone connected with the base2resp. instrument1). In an analogous manner, it is possible to buffer the scan data in the module4and then directly transfer (when connected) to a tablet or other control unit.

Alternatively, data acquired in the stand-alone mode can be transferred wirelessly from module4to the base2for further processing there, particularly on-the-fly or already during measuring. In such embodiments with wireless data transmitters, the data storage of the mobile module4may be only a non-permanent storage and a permanent storage may be dispensable or optional, e.g. in form of an exchangeable storage card inserted in a card reader of module4or e.g. as a back-up to the already transferred data to tablet, smartphone or control unit.

Generally spoken, the geodetic measurement capabilities or range of functions of the geodetic module4are enhanced and extended when combined with the base2to form the geodetic instrument1compared to its stand-alone use. The capacity and functionality of the module4in autonomous application are limited compared to the “full” instrument1.

The described configuration of geodetic instrument1enables first robust and highly reliable geodetic measurements or position true projection by the combination of surveying and/or projection module4and base module2with a high level of geodetic capability/functionality and precision.

Second, the geodetic instrument1is designed such that it may comprise various exchangeable geodetic survey or projection modules4of different type, thus providing different geodetic functionalities with only one and the same basic (infra-)structure (in form of base2) which is described in more detail with respect toFIG. 3. In other words, the geodetic instrument1is configured such that not only one (generic group of) module4is provided but multiple sort of module4can be combined with base2, thus providing a bunch of geodetic capabilities. Geodetic instrument1serves as a multi-purpose geodetic instrument by the possibility to easily exchange the measuring or pointing module4with another one. High flexibility and improved range of application is provided in that the geodetic module4is easily exchangeable by another geodetic module4, i.e. base module2can be combined with different surveying and/or projection modules4.

Third, high flexibility and improved range of application is further enhanced in that the geodetic module4is easily attachable and detachable to the base2and in that it can be used as a semi- or temporarily autonomous geodetic unit, e.g. for quick or supplemental measurements, fast and temporary change of location or locations not or hardly accessible with the complete instrument1. Flexibility of module mounting and dismounting and stationed and free-hand measurement is provided.

FIGS. 2aand 2bshow in a 3D-view an exemplary embodiment of a geodetic instrument1—as for instance intended for geodetic measuring or referencing at a construction site—in more detail.

InFIG. 2a, the geodetic instrument1is depicted with the geodetic survey and/or projection module4docked to the base module2. For attachment, the base2and the surveying and/or projection module4comprise an interface5or that is to say the instrument1comprise an interface5with part of it situated at base2and the counterpart situated at module4. Interface5is shown in more detail inFIG. 2b.

The base module2optionally comprises on its lower side or bottom face2sa connector (not shown) for connection of the instrument1to a stand, e.g. a tripod. Alternatively or additionally, the bottom face2sis designed such, for example as a flat surface or with three contact points, that the instrument1can be placed stable on a surface (bottom) wherefore the instrument1is designed such that the centre of gravity of the instrument1lies securely within bottom surface2s.

As depicted, the exemplary instrument1is asymmetric with respect to the vertical axis V. This facilitates a simple mounting and demounting of the surveying and/or projection module4by an operator.

FIG. 2billustrates the geodetic instrument1with a detached surveying and/or projection module4such that the interface5is visible. Also indicated are the vertical axis V the base2and accordingly the module4attached to the base is rotatable about and the horizontal axis H as a second axis the module4is rotatable about by the interface5when attached with the help of one or more drives and angular sensors which are described in more detail in the following figures. For example, the interface5is integrated in a drive unit for driving the module4about horizontal axis H.

As shown in the upper part ofFIG. 2b, the interface5comprises a mechanical part5a, an electrical connection5band optical connection5c. One can also say that there are two interfaces, a mechanical interface5afor fastening the module4to the base and an optical and electrical interface5b,5cfor energy supply and data transfer, wherein the two interfaces5aand5b,care embodied a joined interface5.

As said, the interface5comprises a mechanical centering and fixation5aas well as an electrical connection5band an optical connection5c. The interface5is designed such that the module4can be mounted to the base2and demounted from the base2very easily, with a only one operation, for example with one translation or rotation, with or preferably without any tool. For example, the interface5comprises a release button for demounting the module4and it has just to be “clicked” onto for mounting. Alternatively, the module4can be slided or pressed onto and off without button release. For example, the interface comprises a single eight-pole connector connecting the geodetic module4with the base2.

Thereby, though the interface5is designed in such a way that fast fastening of various surveying modules4of different type (and therewith often different geometry and mass or mass distribution) is enabled, it is also designed in such a way that a repeatedly stable connection between module4and its base2is guaranteed. That is that the mounting remains positional precise despite environmental influences such a temperature change, various dismounting and mounting procedures and despite the fact that it is embodied as receptacle for various surveying and/or projection units4. Thus, the high precise interface5allows for no shift of an internal reference point of respective module4but any coordinative measuring or projection is precisely referenced with respect to a common reference position, no matter how often there is a module change or how long a measurement tasks takes. The interface5combines easy handling and flexibility with high, stable and reproducible mounting position precision.

FIG. 3shows an example for various surveying and/or projection modules4a-4dof different type which all can be mounted on base2. That is the instrument1is designed such that exchangeability of a geodetic module4a-4dof one type with another one of another type. Hence, the instrument1can advantageously be equipped with different surveying or projection heads, enabling multiple geodetic functionality with one and the same base2as main structure.

FIG. 3depicts the base2comprising mechanical and opto-electrical interface5on the left side and four different exemplary geodetic modules4a,4b,4cand4dwhich each of them can be combined with the base2to form a different geodetic instrument1. Thus, only one base2as basic support-, drive-, energy- and computation-unit, providing defined positioning mechanism, controlling and data evaluation means, energy supply, HMI-elements as well as additional infrastructure such as shock protection, is sufficient for enabling various geodetic measurement and construction aid functionalities. Preferably, each module4a-4dcomprises an identifier, e.g. by RFID, such that the base2can automatically identify which type or which individual module4a-4dis mounted.

First exemplary geodetic module4ais embodied as a telescope surveying head. A measurement beam, generated by a light source (not shown) such as a laser source or SLED inside module4is emitted through objective10onto an object point. The reflected beam is captured through objective10by an optical sensor (not shown) and from the sensor signal a distance to the object point is calculated, e.g. based on TOF or phase measurement. The measurement beam can be visible or an additional visible light beam is generated as a pointer. The module4acan also comprise a camera (with objective10being part of it) such that a user can capture images or a live-stream of the environment and view them on a display of the module4a(not shown).

When used in stand-alone modus, the module4acan be used as an electronic distance meter or camera. In combination with base2, there is provided a geodetic instrument1in form of total station- or electronic tachymeter-type or lasertracker-type.

The second example, geodetic module4b, is designed as a point and line-laser projection module, thus providing functionality of visible marking of spatial references. The point laser11acan for example be used for point pointing or plumbing or perpendicular marking whereas the two (or more) line lasers11b,11ccan mark vertical or—dependent on the orientation of module4b—horizontal reference lines. When dismounted from base2, it can be positioned nearly everywhere whereas a construction laser level or rotary laser as geodetic instrument1is provided in combination with base2. As shown, in the example the first line laser11bis perpendicular to the second line laser11cand the point laser11ais perpendicular to both line lasers11b,11c.

Module4cis a third example and embodied as a laser scanning head. It comprises a rotatable deflection element23for fast deflection of measurement beam such that a dense scan pattern of a high number of 3D coordinates of an object's surface can be acquired.

The fourth example is module4d, embodied as a multi-photo measuring head. It comprises a number of photosensors or photodetectors24distributed on a housing of the module4d.

FIG. 4illustrates another example of a tool-freely mountable and dismountable geodetic surveying and projection module4e, providing specific geodetic functionality and being non-permanently or limitedly usable as a stand-alone geodetic unit. Module4ecomprises a surveying telescope40for coordinative measuring of object points using a measurement beam41. Further, the module4ecomprises a horizontal projecting line laser42and a vertical projection line laser43as well as an orthogonal projection point laser44. In the example as can be seen, the emission direction or plane of each of the two line lasers42,43are perpendicular to each other as well as to the emission direction of point laser44.

For capturing images of the surrounding or surveying environment, the module4ehas a panorama camera objective46on the top as well as a wide angle objective47on one side whereby both objectives can be part of a combined panorama and wide angle camera. In addition, geodetic module4ecomprises an illumination light45as sort of flashlight for illumination of a target object or field of view of the telescope40and/or camera objectives46,47.

FIG. 5ais a cross-sectional view of the geodetic instrument1with the asymmetrical base part2to the left and bottom and the detachable module unit4to the upper right.

The surveying and/or projection module4comprises a battery16, a data processing unit17with a permanent or non-permanent data storage and a surveying and/or projection unit18.

The base module2comprises a lower part with a battery14for providing energy to the base2, e.g. the motors for change of orientation, a processor15, and through interface5to the module4. Instead of or in addition to a battery14, the base2comprises a power supply unit for connection to an external power supple. Further, an inclinometer sensor25is part of the base2for measuring a tilt of instrument1.

The base2comprises above that in its lower part a first or vertical drive unit13for rotation of the base2and therewith module4(if attached) about the vertical axis V. In addition, the upper part comprises a second or horizontal drive unit12for rotation of the module4about horizontal axis H. In the example, the interface5and an angle encoder are integrated in the drive unit12which shown in more detail inFIG. 5b. Preferably, first and second drive unit12and13are substantially structurally identical, except for interface5. As can be seen, base2is asymmetrical with respect to axis V due to the non-centric upper part, situated at one side of the lower battery part.

FIG. 5bshows the first (or similarly second) drive unit12in detail. The drive unit comprises a motor19, an angular measuring system or angular sensor20and an axle bearing21. Further, it shows interface5with mechanical centering and fixation5a, electrical contact5band optical interface5c. The presented drive unit12resp.13provides a compact and nevertheless reliable and robust mean for precise rotation of geodetic instrument1resp. change of its aiming or targeting direction.

FIG. 6shows a variation of the embodiment as shown inFIG. 5a. In difference to this above described embodiment, the battery or power unit part2b, comprising battery14, is separated from and superimposed on the main part2aby an interface5′, the main part2acomprising CPU15, second drive12and first drive13. By first drive13, the main part2aand thus module4is drivable around the vertical axis and relative to battery part2b. Thus, the relatively heavy power unit14has not to be moved which saves energy.

Preferably, the power unit part2bis detachable tool free from the main part2a. This allows for a quick and easy exchange or replacement of battery14, without the need for a longer interruption of the geodetic work.

In particular advantageous embodiments, the whole instrument1is temporarily supplied with energy through interface5by the module battery16during exchange of main battery14or in case of any failure in power supply by base battery14. Thus, advantageously, there is an electrical reserve in form of module battery16in case of low or broken main battery14. This allows for a limited continuation of operation (limited with respect to time and/or functionality) which is e.g. particularly advantageous in case of measurements which otherwise would have to be repeated completely from the beginning. At least, an “emergency” power reserve by module battery16prevents loss of data as at least it gives time to permanently store measurement data before instrument1is off.

FIGS. 7aand 7billustrate a way of position stable fixation of two separable modules or units of the geodetic instrument with respect to each other by a mechanic interface5a.

FIG. 7ashows in the upper part two 3D views of (part of) mechanical interface5aas used for mounting or connection of a surveying or projection module and base module. In the lower part, there are two side and cross sectional views. On the left side,FIG. 7adepicts the reception part and the insertion part separated or dismounted (semi-exploded view) and the right side depicts the interface5awhen the modules are attached to each other.

As shown, the interface5acomprises three balls27fixed in conical receptions (bores)28, distributed equally around a center (120° angular spacing) and being part of the base module2. The balls27are to be clamped by a pair of elongated cylindrical guiding elements26each situated in the interface's counterpart at surveying module4. The clamping is for example effected by magnetic force. Therefore, for instance the cylinders26are made of steel and the balls27are made of steel or ceramic and a magnet either in the center of the arrangement (not shown) or located around the balls (not shown) are pulling the two parts4and2towards each other (see alsoFIG. 8a). This configuration results in a self-centering coupling.

A possible alternative to the configuration shown inFIG. 7aas a robust and tolerance independent interface, which can compensate for thermal expansion, too, the fixation50comprises three equally spaced cylinders26(or elongated prismatic bodies) clamped into a pair of balls27each. That is to say, in difference to the embodiment shown inFIG. 7a, not the balls27are fixed by cylinders26but the other way round.

FIG. 7bshows in a sketchy cross-sectional view another alternative illustrating the underlying principle of a positional stable interface. The base module2comprises three spherical calottes27adistributed in an area or plane. The calottes27aare received by a two-point reception26aaccordingly distributed at the interface at surveying module4.

FIGS. 8a-8fshow in cross sectional views examples for fastening means as an instrument's mechanical interface or part of it, e.g. for convenient and user-friendly but nevertheless position stable mounting and dismounting a surveying and/or projection module4to the base module2(each depicted in a respective figure only symbolically).

FIG. 8ashows a first example using magnetic force as already mentioned above. The instrument thereby comprises a set of magnets29a,29b. A first group of magnets29a, situated at dismountable part4exert force on a second group of magnets29b, situated at the static part2. Surveying module4thus can be mounted by docking onto base part2and dismounted by pulling it away.

FIG. 8bshows another example wherein the interface is secured by a screw30bat base part2going into a thread30aat mobile part4. The screw30bthereby can be revolved tool-free by hand as depicted or alternatively is designed for manipulation with a specialized tool like a screwdriver or an item like a coin or key fob as a tool.

FIG. 8cshows an embodiment wherein a pin31ais to be secured by a claw31bat base part2, the claw31bbeing preloaded with a spring31c(indicated by the black dots). The claw31band the interface at base part2thereby are formed in such a way that a force is exerted in the mounted state due to spring31c.

FIG. 8dshows an embodiment having a bayonet fastening32, whereby in the lower part ofFIG. 8din addition a birds-eye view is given. Module4comprises the inner part32aof the bayonet fastening and module2the outer (counter-)part32b.

FIG. 8eshows another embodiment with a claw33b. Therein, a pin33ais to be secured by a claw33bat base part2, the claw33bbeing rotatable as indicated in lower part ofFIG. 8e, showing a 3D-view of claw33b.

FIG. 8fshows an example with a ball lock pin34bat base part2for being secured by reception34aat module4for fixation.

Preferably, the mechanical interface comprises not more than one of such a fixation means as depicted inFIGS. 8b, 8c, 8eand 8f. Thus, in all examples one movement of a user's hand is sufficient for mounting or dismounting (fix and unfix) of a separable unit of the geodetic instrument.

A skilled person is aware of the fact that details, which are here shown and explained with respect to different embodiments, can also be combined in other permutations in the sense of the invention if not indicated otherwise.