Device and method for generating a reference plane

Abstract

In a device and a method for generating a reference plane, a radiation transmitter (118), designed, for example, as a rotating laser, is provided, which is configured to rotate a measuring beam (121) in a plane at relatively constant angular velocities in two directions of rotation. A signal transmitter is configured to detect at least one predetermined angular value assigned to a direction of the measuring beam (121). Furthermore, computing and evaluation units of the radiation transmitter (118) and of a radiation receiver (130) have timers that run synchronously except for a temporally constant but unknown phase shift. This allows the position of a radiation receiver (130) with respect to a reference direction linked to the radiation transmitter (118) to be determined with relatively little effort.

Description

The invention relates to an apparatus for generating a reference plane according to the preamble of claim 1.The invention further relates to a method for generating a reference plane.Such an apparatus and a method for generating a reference plane are known from EP 2 781 879 A1. This previously known device has a radiation transmitter designed as a rotating laser, which is designed to emit a measurement beam rotatably about an axis of rotation over an angle range and pivotable relative to a reference plane about at least one axis into a reference plane. A radiation receiver is provided for detecting the measurement beam at a setup position, wherein the radiation receiver has a receiver data processing unit which is configured to emit a detection signal after a passage of the measurement beam is detected. Furthermore, the aforementioned device is equipped with a central data processing unit which is configured to receive detection signals of the or at least one radiation receiver and to determine the direction of the installation position of the relevant radiation receiver with respect to a reference direction on the basis of the detection signals. For this purpose, the different ranges of the angle of rotation are distinguished by code patterns assigned to one angle of rotation range in each case.Further devices for generating a reference plane are known from EP 2 000 767 A2, DE 10 2011 054 224 A1, U.S. Pat. No. 6,693,706 B2 and DE 10 2010 061 725 A1.The object of the invention is to specify a device and a method of the type mentioned at the beginning which is distinguished by a relatively simple design for determining the installation position of a radiation receiver at a relatively high angular resolution.This object is achieved in a device for generating a reference plane of the type mentioned at the beginning with the characterizing features of claim 1.This object is achieved in a method for generating a reference plane having the features of claim 8.Because in an apparatus and a method according to the invention the measuring beam rotates in two directions of rotation, time differences in the time systems of the receiver data processing unit and the central data processing unit can be eliminated and the directions of installation positions of the or each radiation receiver concerned can be determined relatively accurately.Further expedient embodiments of the invention are the subject matter of the dependent claims.Further expedient configurations and advantages of the invention are evident from the following explanation of exemplary embodiments with reference to the figures of the drawing.The following are shown: FIG. 1 shows in a schematic perspective view an embodiment of an exemplary apparatus for generating a reference plane by means of a measurement beam with a rotating laser as radiation source and with two radiation receivers, FIG. 2 is a block diagram showing essential components of the rotating laser and a radiation receiver in the embodiment of FIG. 1, FIG. 3 shows in an illustrative illustration the relationships when arranging a radiation receiver with respect to a polar coordinate system of a rotating laser with an installation axis at an angular distance from a laser sensor axis in the embodiment according to FIG. 1, FIG. 4 shows, in a further illustrative illustration, the relationships according to FIG. 3 over an angle range of less than 180 degrees with indicated opposite directions of rotation of the measurement beam, and FIG. 5 shows a graph in an exemplary embodiment of the time relationships in the case of the rotating laser and a radiation receiver during revolutions of the measurement beam.FIG. 1 shows a schematic perspective view of an embodiment of an exemplary device for generating a reference plane according to the invention. In the illustration according to FIG. 1, a construction base 103 is illustrated with a horizontal placement plane 106, for example, and with a construction plane 115 to be measured which is inclined with respect to the placement plane in an X axis 109 and in a Y axis 112. Conveniently, but not necessarily, the X-axis 109 and the Y-axis 112 are oriented perpendicular to each other for high user experience.The exemplary embodiment explained below has a rotating laser 118 as a radiation transmitter, which is configured to rotate a measurement beam 121 about an axis of rotation over an angle range and to pivot with respect to a reference plane, for example the placement plane 106, about at least one axis, but preferably about two axes such as the X axis 109 and the Y axis 112 into a reference plane, for example into a plane parallel to the construction plane 115.The rotating laser 118 is rotatably shown in FIG. 1 and is preferably also pivotably mounted for coarse alignment and is adjustably vertically mounted on a rotatable-leg stand 124. The stand 124 is arranged in the illustration according to FIG. 1 such that its perpendicular foot 127 lies in the transition region of the construction plane 115 into the placement plane 106.Furthermore, the exemplary embodiment according to FIG. 1 has two radiation receivers 130, which are configured to detect the measurement beam 121 at a respective placement position. In the embodiment of FIG. 1, the radiation receivers 130 are releasably fixedly supported by a receiver support 133 while the receiver support 133 is again slidably mounted in the longitudinal direction of a support rod 136 and is rotatable together with the support rod 136. The retaining rods 136, in turn, are set up substantially upright in the construction base 103, in the illustration according to FIG. 1, for example in the installation plane 106, and secured against unintentional tilting or even dropping over.FIG. 2 shows, in a block diagram, essential components of the rotating laser 118 and of a radiation receiver 130 of the exemplary embodiment according to FIG. 2, the rotating laser 118 has an operating unit 203 which is formed with a laser light module 206 for generating the measurement beam 121 and with a rotating module 209 for rotating the measurement beam 121 in two rotational directions, namely, on the one hand, clockwise and, on the other hand, counterclockwise, over a predetermined angular range, expediently over an angular range of 360 degrees. The rotation module 209 is configured to generate rotation direction identifiers assigned to the respective rotation direction. Furthermore, the operating unit 203 is designed with an inclination sensor module 212 having a number of inclination sensors for detecting the effective inclination of the measurement beam 121 with respect to a reference plane.In the first embodiment of an operating unit 203 illustrated in FIG. 2, a signal module 215 is present, which is configured to generate rotation angle-dependent signals.In a first embodiment, the signal module 215 is designed as an angle measuring module which is configured to directly detect the respective angle of rotation of the measuring beam 121 with respect to a reference direction intrinsic to the rotation module 209 during the rotation of the measuring beam 121.In a second embodiment, the signal module 215 is designed as a pulse signal generator which is designed to generate at least one pulse signal as an index mark per revolution of the measuring beam 121. In particular, in the second embodiment, it is advantageous that the rotation module 209 provides a relatively high synchronism in both rotational directions, that is to say in each case a temporally constant and expediently also an identical angular speed in both rotational directions.The operating unit 203 is connected for bidirectional data exchange with a computing and evaluation unit 218 of the rotating laser 118 as a central data processing device, which in this exemplary embodiment is in turn connected to a timer 221. The timer 221 of the rotating laser 118 is configured to generate time stamps on a predetermined time scale explained in more detail below and to feed them to the computing and evaluation unit 218 of the rotating laser 118.Furthermore, an inclination setting unit 224 for receiving setting signals from the computing and evaluation unit 218 of the rotating laser 118 is connected to the computing and evaluation unit 218 of the rotating laser 118. The inclination adjustment unit 224 is configured to adjust the inclination of the measurement beam 121 with respect to at least one axis, but preferably about two axes such as the X axis 109 and the Y axis 112.Furthermore, the computing and evaluation unit 218 of the rotating laser 118 is connected to a communication unit 227 of the rotating laser 118 via a bidirectional data connection. As explained in more detail below, the communication unit 227 of the rotating laser 118 is configured to exchange data with the radiation receiver 130 via a preferably wireless communication link 230.The radiation receiver 130, in turn, has a laser sensor unit 233 which is configured to detect the passes of the measurement beam 121.The laser sensor unit 233 is connected to a computing and evaluation unit 236 of the radiation receiver 130, which is configured, inter alia, to receive output signals of the laser sensor unit 233 and to store them together with time stamps which can be generated by a timer 239 connected to the computing and evaluation unit 236.Certain data of the computing and evaluation unit 236 of the radiation receiver 130 can be fed to a display unit 242 for visual recording by a user of a device according to the invention.The radiation receiver 130 is furthermore equipped with a communication unit 245 which is configured to exchange data with the arithmetic and evaluation unit 236 of the radiation receiver 130 and feed it to the communication connection 230.According to the invention, the timers 221, 239 are concurrent in the sense that they have the same time period for a periodic time cycle or equal time increments for a linearly progressive time scale, but run with a certain but constant phase shift with respect to one another. In this respect, the time stamps generated by the timers 221, 239 are, with knowledge of this phase shift which is usually initially unknown and which can be determined as explained in more detail below, comparable to one another and can be fed back to a common time system.FIG. 3 shows, in an illustrative illustration, the relationships when arranging a radiation receiver 130 with respect to a rotation laser 118 in a coordinate system determined by the X axis 109 and by the Y axis 112, with an installation axis 303 as connecting line between the rotation laser 118 and the radiation receiver 130 and with an angular spacing of the radiation sensor axis of the radiation receiver 130 from the Y axis 112.Furthermore, a reference plane 306 is shown in the illustration according to FIG. 3 bounded by an outer circle running through the radiation receiver 130, in which reference plane the measurement beam 121 currently coinciding with the placement axis 303 in the illustration according to FIG. 3 runs. It can be seen from FIG. 3 that the placement axis 303 of the radiation receiver 130 has a deposition angle 309 which is different from 90 degrees or from 0 degrees with respect to the X axis 109 and thus also with respect to the Y axis 112, the exact value of which is initially unknown when the measurement beam 121 passes through the radiation receiver 130 even on account of an unknown phase shift in the case of uncoupled, freely running timers 221, 239, even with the same clock time or the same time scale between the time stamps of the timers 221, 239.FIG. 4 shows, in a larger illustrative illustration, the relationships according to FIG. 3 over an angle range of less than 180 degrees. It can be seen from the illustration according to FIG. 4 that, in the case of an angle measurement according to the first embodiment with an angle measurement module as signal module 215, a right-time stamp can be generated in each case at a first rotational direction R of the measurement beam 121 in the clockwise direction, i.e. in a so-called right direction, at a predetermined first position 403 and at a predetermined second position 406 on the time scale of the timer 221 of the rotary laser 109, or a left-time stamp can be generated in each case at a first rotational direction L of the measurement beam 121 in the counterclockwise direction, i.e. in a so-called left direction, at the predetermined first position 403 and at the predetermined second position 406 on the time scale of the timer 221 of the rotary laser 109.Accordingly, when the rotational direction is reversed in a second rotational direction L of the measurement beam 121, i.e. counter-clockwise or in the left direction, two left-time stamps can be generated at the aforementioned predetermined position 403, 406 of the rotation laser 118 or two right-time stamps can be generated at the aforementioned predetermined positions 403, 406 of the rotation laser 118 in a second rotational direction R of the measurement beam 121, i.e. clockwise or in the right direction, at the aforementioned predetermined positions 403, 406 of the rotation laser 118.In the aforementioned first embodiment with an angle measuring module as signal module 215, predetermined positions 403, 406 are determined by predefined angle values of measuring beam 121.In the aforementioned second embodiment with a pulse signal generator as signal module 215, the predetermined positions 403, 406 are determined by predetermined points in time with respect to the pulse signal during a passage of the measuring beam 121 at constant, but not necessarily identical, angular speeds of the measuring beam 121 in each of the rotational directions L, R.When the measuring beam 121 passes through the radiation receiver 130, a receiver time stamp generated by the timer 239 of the radiation receiver 130 can be generated at a setup position 409 of the radiation receiver 130, which can be fed in via the communication connection 230 of the computing and evaluation unit 218 of the rotating laser 118.FIG. 5 shows a graph in an exemplary embodiment of the time relationships for the rotating laser 118 and a radiation receiver 130 during revolutions of the measuring beam 121.In the illustration according to FIG. 5, a time axis 503 for the time values t of the timer 221 of the rotating laser 118 is illustrated in dimensionless units. Furthermore, an angle scale 506 of the rotary laser 118 is shown in dimensionless units, on which the angular position α is also shown in dimensionless units in the case that the rotary laser 118 is equipped with an angle measurement module for explicit angle measurements according to the first embodiment of the exemplary embodiment explained above.Furthermore, FIG. 5 shows a time beam 509 for the direction of rotation R of the measurement beam 121 and a time beam 512 for the direction of rotation L of the measurement beam 121.Further, the graph of FIG. 5 shows a time axis 515 for the time t of the timer 239 of a radiation receiver 130 in dimensionless units.In the following, with reference to a constellation, to be considered purely by way of example, for the first embodiment with an angle measuring module as signal module 215, the sequence of a measurement for determining the direction of the installation position 409 of a radiation receiver 130 with respect to a reference direction of the rotation laser 118 is explained when the measurement beam 121 is rotated in the direction of rotation R, i.e. in the right direction.During a rotation of the measuring beam 121 in the direction of rotation R, a first right-time stamp is recorded at the first position 403 at a time t 1R, in the diagram according to FIG. 5 with t 1R= 18. In the further course, a receiver time stamp t ER, is recorded at a radiation receiver 130 at the setup position 409 in the diagram according to FIG. 5 with t ER= 516. Next, in the case of the rotary laser 118, at the second position 406, a second right-time stamp t 2R, in the diagram according to FIG. 5, is recorded with t 2R= 50.Since for the first embodiment with an angle measuring module as signal module 215 the positions 403, 406 are known in their angular positions α 1, α 2 a right-hand angular velocity ω R can be determined from the difference of the right-hand time stamps t 1R, t 2R with the assumption of an angular velocity constant during the rotational direction R at least between the positions 403, 406, with ω R= 1,25. in the diagram according to FIG. 5.In a rotational direction L of the measurement beam 121 in the left direction, the following conditions prevail for the first embodiment with an angle measurement module as signal module 215.During a rotation of the measuring beam 121 in the direction of rotation L, a first left-time stamp is recorded at the second position 406 at a time t 2L, in the diagram according to FIG. 5 with t 2L= 170.In the further course, a receiver time stamp t EL, in the diagram according to FIG. 5 with t EL= 696. is recorded at a radiation receiver 130 at the setup position 409. Next, in the case of the rotary laser 118, a second left-time stamp t 1L, is recorded at the first position 403 with t 1L= 218. in the diagram according to FIG. 5.Since for the first embodiment with an angle measuring module as signal module 215 the positions 403, 406 are known in their angular positions α 1, α 2 a left-hand angular velocity ω L can be determined from the difference of the left-hand delay stamps t 2L, t 1L with the assumption of an angular velocity constant at least between the positions 403, 406 during the rotational direction L, with ω L= 0,83. in the diagram according to FIG. 5.In the following, with reference to a constellation, to be considered purely by way of example, for the second embodiment with a pulse signal transmitter as signal module 215, the sequence of a measurement for determining the direction of the set-up position 409 of a radiation receiver 130 in relation to a reference direction of the rotation laser 118 is explained when the measurement beam 121 is rotated clockwise in the direction of rotation R, i.e. in the right direction.When the measuring beam 121 rotates in the direction of rotation R at a constant angular velocity, a receiver time stamp t ER, is recorded at a radiation receiver 130 at the setup position 409 in the diagram according to FIG. 5 at t ER= 516. Next, in the case of the rotation laser 118, a right-time stamp t 0R, is recorded at the index mark in the diagram according to FIG. 5 with t 0R= 34.In the case of a counterclockwise direction of rotation L of the measurement beam 121 in the left direction, the following conditions prevail for the second embodiment with a pulse signal generator as signal module 215.When the measuring beam 121 rotates in the direction of rotation L at a constant angular velocity, a receiver time stamp t EL, is recorded at a radiation receiver 130 at the setup position 409 in the diagram according to FIG. 5 at t EL= 696. Next, in the case of the rotation laser 118, a left-time stamp t 0L, is recorded at the index mark in the diagram according to FIG. 5 with t 0L= 193.Since the position of the index mark is known for the second embodiment with a pulse signal transmitter as signal module 215, the position of the radiation receiver 130 in relation to the index mark can be determined with angular speeds which are constant in both rotational directions R, L but not necessarily the same from the differences between the right-time stamp t 0R and the receiver time stamp t ER or the left-time stamp t 0L and the receiver time stamp t EL respectively.Exemplary procedures for a method according to the invention for determining the direction of the installation position of a radiation receiver 130 are explained below on the basis of the explanations with respect to the exemplary embodiment according to the invention explained above.In the first procedure with the first embodiment of the above-explained embodiment with explicit angle measurement, the determination of the exit angle of the measurement beam 121 in values of the angle measurement module 215 and the determination of the direction of the sensor axes of the inclination sensors of the inclination sensor module 212 take place in initial steps.In a next step, the radiation receiver 130 in the construction field 103 is brought to a set-down position 409.Subsequently, the rotating laser 118 is first relatively coarse and then finely aligned on the radiation receiver 130 in an automated capture process known per se until the reference plane 306 hits the laser sensor unit 233 of the radiation receiver 130. Thus, with the radiation receiver 130, for each pass of the measurement beam 121, a pass signal provided with a time stamp of the timer 239 of the radiation receiver 130 is transmitted as a function of the respective rotational direction L, R at times t EL, t ER.Time stamps of the rotation laser 118 are recorded on the side of the rotation laser 118 at two predetermined angular positions, for example at the first position 403 and at the second position 406 according to FIG. 4.The aforementioned steps take place in the case of a first rotational direction of the rotating laser 118, for example in the case of a clockwise rotation in the rotational direction R.Subsequently, the direction of rotation of the rotating laser 118 is reversed into a second direction of rotation, i.e. for example into a counterclockwise rotation in the direction of rotation L, and expediently it is waited until the measuring beam 121 moves again at a constant angular speed.Subsequently, time stamps are detected at the predetermined positions 403, 406 and the time stamp is detected when the measurement beam 121 passes through the radiation receiver 130.On the basis of this, the direction of the installation position 409 of the radiation receiver 130 with respect to a reference direction of the rotating laser 118 is determined as follows.In a first step, the angular speeds when the measuring beam 121 is moved counterclockwise in the direction of rotation L or when the measuring beam 121 is rotated clockwise in the direction of rotation R are determined according to equations (1.1) and (1.2) as follows: ω L: angular speed when the measuring beam 121 is moved counterclockwise in the direction of rotation L ω R: angular speed when the measuring beam 121 is moved clockwise in the direction of rotation R α 1: angle at the first position 403 α 2: angle at the second position 406 t 1L: time stamp of the rotating laser 118 at the first position 403 when it is rotated counterclockwise in the direction of rotation L t 1R: time stamp of the rotating laser 118 at the first position 403 when rotating clockwise in the rotational direction R t 2L: time stamp of the rotating laser 118 at the second position 406 when rotating counterclockwise in the rotational direction L t 2R: time stamp of the rotating laser 118 at the second position 406 when rotating clockwise in the rotational direction RThe time stamps at the radiation receiver 130 at the times t EL, t ER in the rotational directions L, R generally have an initially unknown but constant phase shift or time offset ΔT compared to the time stamps t 1L, t 1R, t 2L, t 2R of the rotary laser 118, wherein the following relationship applies when using the times t 1L and t 1R:Solving equation (1.2) according to ΔT yields:In an alternative method of using the points in time t 2L and t 2R the following relationship applies:Solving equation (1.4) for ΔT yields:Expediently, in order to reduce error influences, averaging for the phase shift ΔT is carried out from equations (1.3) and (1.5).The angular position ε of the radiation receiver 130 with respect to the angle measuring system of the rotating laser 118 is determined according to one of the following equations:For determining the angular position ε of the radiation receiver 130, an averaging of at least two of the equations (1.6) to (1.9), particularly preferably of all equations (1.6) to (1.9), is also expedient in order to reduce error influences.The method according to the invention for determining the direction of the installation position 409 of a radiation receiver 130 with respect to a reference direction of the rotating laser 118 with the second embodiment of the exemplary embodiment explained above having a pulse signal transmitter as signal module 215 proceeds in a further procedure as follows.First, as in the method explained above, the rotating laser 118 is aligned such that the measurement beam 121 strikes the laser sensor unit 233 of the radiation receiver 130 and this sends a time stamp determined by the timer 239 of the radiation receiver 130 to the rotating laser 118 at times t EL, t ER with each pass of the measurement beam 121 in the two rotational directions L, R.At a comparatively accurately constant angular speed in a rotational direction, for example, counterclockwise in the rotational direction L, at an index mark at a relative angular value predetermined in time and with respect to the relative angular value determined by the position of the index mark, but with respect to the absolute angular value in the coordinate system of the rotating laser 118, first basically, that is, in the case of not determining the angular value upon mounting, the indefinite index angular position α 0, which is determined in the second embodiment by the pulse signal generated by the pulse signal generator at time t 0L the detection of a time stamp generated by the timer 221 of the rotating laser 118 takes place.Subsequently, the rotational direction is reversed, for example, clockwise in the rotational direction R, and waiting until the angular speed of the rotating laser 118 is constant in the new rotational direction.At a relatively accurately constant angular velocity in this new rotational direction, for example, clockwise in the rotational direction R, at the index mark at the predetermined index angular position α 0, which is determined in the second embodiment by the pulse signal generated by the pulse signal generator at time t OR a time stamp generated by the timer 221 of the rotary laser 118 is detected.On the basis of this, in the second embodiment, the arithmetic determination of the direction of the installation position 409 of the radiation receiver 130 is made as follows.In a first step, the angular velocity upon a counterclockwise rotation of the measuring beam 121 in the direction of rotation L is determined according to equation (2.1) as follows: with τ L: cycle time upon a clockwise movement of the measuring beam 121 in the direction of rotation L via the index mark, unless already explained aboveSubsequently, in a second step following the first step, the angular velocity when the measuring beam 121 is moved clockwise in the direction of rotation R is determined according to equation (2.2) as follows: where, unless already explained above, τ R: cycle time when the measuring beam 121 is moved counter-clockwise in the direction of rotation R via the index mark Due to the fact that, as in the first embodiment, different time differences in the directions of rotation L, R with different angular velocities ω L, ω R correspond to identical angular differences, the correlation for the initially unknown phase shift ΔT and for the angular position ε of the radiation receiver 130 with respect to the position of the rotating laser 118 in the direction of rotation L and in the direction of rotation R results from the correlationIn the second embodiment, for determining the angular position ε of the radiation receiver 130 in order to reduce error influences, an averaging from the two equations (2.5) and (2.6) is expedient.It can thus be seen that, for a relatively accurate determination of the direction of the installation position 409 of a radiation receiver 130 with respect to a reference direction of the rotating laser 118, signals in the form of time stamps which are easy to process from a data standpoint are used in the case of concurrent timers 221, 239 of the rotating laser 118 or of the radiation receiver 130, the timers 221, 239 are used with the elimination of constant phase shifts which may possibly be present between the timers 221, 239, without latencies in the communication link 230 playing any role. For a computational correction of the coordinate system of the rotating laser 118 to the coordinate system of the radiation receiver 130, knowing the angular position ε obtained, a relatively simple construction is thus created.In a development of an apparatus and a method according to the invention, it is provided that the phase shift between the timers 221, 239 is determined from the above-explained determination of the actual angular position of the radiation receiver 130, and, provided that the angular speeds ω L, ω R are constant over time over the entire revolution and the value of the phase shift is constant, the angular position of the radiation receiver 130 is determined at each installation position 409 of the radiation receiver 130, without latencies playing any role in the communication link 230.As soon as the determination of the time difference Δt, i.e. a phase shift, between the two timers 221, 239 has been completed, the direction of the installation position of a radiation receiver 130 can be determined at any desired position. For this purpose, the radiation receiver 118 sends one of its previously explained time stamps t EL, t ER to the rotating laser 118 as soon as a measurement beam 118 has been detected.With one of the above-mentioned computing rules (1.6) to (1.9) for determining the angle value ε, a direct direction determination of the installation position of the radiation receiver 130 can thus be carried out.Only the respective rotational direction L, R of the rotating laser 118 and thus the corresponding selection of the computing rule, namely the equation (1.8) or the equation (1.9) for the counterclockwise rotational direction L in the left direction, otherwise the equation (1.6) or the equation (1.7) for the clockwise rotational direction R in the right direction, should be noted. The values to be considered constant for this case for the variables α1, α 2, t 1L, t 2L, t 1R and t 2R explained above can be adopted unchanged, namely as used for determining the time difference Δt.In the first embodiment with the signal module 215 designed as an angle measuring module, the previously determined angular velocity ω L, ω R between the angular positions α 1 and α 2 is assumed to be constant over the entire rotation range of the rotary laser 118.In order to reduce inaccuracies, it is also expedient here to change the direction of rotation L, R of the rotating laser 118 and thus to use both directions of rotation L, R with averaging for determining the angular position ε.In the second embodiment with the signal module 215 designed as a pulse signal generator, the respective angular velocity ω L, ω R is determined forcibly on the basis of a complete revolution of the measurement beam 121, with the proviso that the angular velocity ω L, ω R. is accordingly constant.As soon as the radiation receiver position 409 is at least roughly determined, the emission of the measurement beam 121 is expediently carried out only in a relatively small angular range in which the radiation receiver position 409 and thus the radiation receiver 130 is located. This makes it possible to largely avoid interference with other optical systems in the construction field 103.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedEP 2 781 879 A1

[0003] EP 2 000 767 A2

[0004] DE 10 2011 054 224 A1

[0004] U.S. Pat. No. 6,693,706 B2

[0004] DE 10 2010 061 725 A1

[0004]

Claims

Apparatus for generating a reference plane (306), having a radiation transmitter (118) which is configured to emit a measurement beam (121) rotatably about an axis of rotation over an angle range and pivotably relative to a reference plane about at least one axis (109, 112) into a reference plane (306), having at least one radiation receiver (130) which is configured to detect the measurement beam (121) at a setup position (409) and which has a receiver data processing unit (236) which is configured to emit a detection signal after detection of a passage of the measurement beam (121), and having a central data processing unit (218) which is configured to emit a detection signal, Detection signals of the or at least one radiation receiver (130) and to determine the direction of the installation position (409) of the relevant radiation receiver (130) with respect to a reference direction on the basis of the detection signals, characterized in that the radiation transmitter (118) is configured to rotate the measurement beam (121) in two rotational directions (L, R) and to feed a rotational direction identifier assigned to the respective rotational direction (L, R) to the central data processing unit (218), and in that the central data processing unit (218) is configured to determine the direction of the installation position (409) of at least one radiation receiver (130) with respect to the reference direction on the basis of detection signals obtained in the two rotational directions (L, R).Device according to Claim 1, characterized in that the central data processing unit (218) and the receiver data processing unit (236) each have a timer (221, 239) which are synchronous except for a temporally constant phase shift.The apparatus of claim 2, characterized in that each timer (221, 239) is arranged to generate its own time stamps.Device according to Claim 3, characterized in that the timer (221) assigned to the radiation transmitter (118) is configured, during a rotation at two predetermined angle values (α 1, α 2), which are assigned to two beam directions of the measurement beam (121), to feed in the associated time stamps of the central data processing unit (218), and in that the timer (239) assigned to the receiver data processing unit (236) is configured to feed in its time stamp generated during this rotation of the measurement beam (121) to the receiver data processing unit (236).Device according to Claim 4, characterized in that a signal module (215) which is designed as an angle measuring module is present and is designed to determine angle values (α 1, α 2) in the coordinate system of the radiation transmitter (118) at the two predetermined beam directions.Device according to Claim 3, characterized in that the beam rotation unit (209) has an angular velocity which is sufficiently constant for a predetermined accuracy for determining the direction of the installation position (409) of the at least one radiation receiver (130) in each of the two rotational directions (L, R), in that the timer (221) assigned to the radiation transmitter (118) is configured to feed the associated time stamps of the central data processing unit (218) during a rotation of the measurement beam (121) at two predetermined times, and in that the timer (233) assigned to the receiver data processing unit (236) is configured to feed its time stamp generated during this rotation of the measurement beam (121) to the receiver data processing unit (236).Device according to Claim 6, characterized in that a signal module (215) designed as a pulse signal transmitter is present, which is designed to generate at least one pulse signal as an index mark per revolution of the measurement beam (121).Method for generating a reference plane (306), comprising - providing an apparatus according to one of claims 1 to 7, - moving the measurement beam (121) in a first rotational direction (L, R) and obtaining detection signals from at least one radiation receiver (130) when the measurement beam (121) passes through, - feeding the detection signals into the central data processing unit (218), - moving the measurement beam (121) in a second rotational direction (R, L) opposite the first rotational direction (L, R), - feeding the detection signals of the radiation receiver (130) into the central data processing unit (218) and - determining the direction of the installation position (409) of a radiation receiver (130) with respect to a reference direction.Method according to Claim 8, insofar as an apparatus according to Claim 4 or according to Claim 5 is provided, characterized in that time stamps of the timer (221) assigned to the radiation transmitter (118) are obtained at two predetermined beam directions of the measurement beam (121).Method according to Claim 8, provided an apparatus according to Claim 6 or according to Claim 7, characterized in that, with a respectively constant angular speed in each of the two rotational directions (L, R), time stamps of the timer (221) assigned to the radiation transmitter (118) are obtained at two predetermined times.

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