Abstract: A construction machine, in particular in the form of a crane, cable excavator or similar, comprising an electronic control device for controlling and/or detecting operating parameters, in addition to at least one drive device for moving a functional element, especially a load take-up means. The functional element of the construction machine is guided in the desired direction by the exertion of manipulation forces on the functional element, or on a component fastened thereto, or the functional element is moved manually in a designated direction, this motion then being assisted by the drives of the construction machine. If the functional element is manually pressed or pulled in a designated direction and/or rotated, or if this is at least attempted, these motion attempts are detected and converted into a corresponding positioning motion of the construction machine.

Abstract: An improved eye tracking illumination system is disclosed. The system includes (i) an RGB laser device that is associated with a first collimating optic and (ii) an IR illumination device that is associated with a second collimating optic. The system also includes a DMA that has a MEMS mirror system. The DMA optically combines IR light and RGB light to generate combined light. The combined light is then directed towards a user's eye via a transport medium (e.g., a waveguide). One or more photodetector(s) are positioned to capture reflected light that is reflected off of the user's eye. The photodetectors include an IR detector configured to detect reflected IR light off of the user's eye in order to perform eye tracking.

Abstract: The present invention discloses a synchronization method for multi-station data of dynamic coordinate measurement by a workshop measuring and positioning network. The method comprises the following steps of: determining a measuring and positioning space according to the in-situ measurement dimension, selecting locations for placing several transmitters, calibrating external parameters of the transmitters by a reference ruler, and establishing a measurement field; in a communication data packet of a signal processor, attaching local clock information into the angle information of each transmitter; and setting fixed time nodes on a time axis, and synchronizing data of different transmitters to corresponding time nodes so as to realize data synchronization.

Abstract: A system for mounting a sensor on a construction machine is described. The system includes a sensor having a bottom interface and a base for mounting the sensor on a construction machine. The base includes a top interface for rotatably interlocking with the bottom interface of the sensor. The rotatably interlocking of the base with the bottom interface of the sensor causes one or more terminals of the bottom interface of the sensor to communicatively couple to corresponding terminals of the top interface of the base.

Abstract: A lidar apparatus including a laser transceiver assembly, a wireless charging assembly and a driving assembly is provided. The wireless charging assembly is coupled to the laser transceiver assembly. The wireless charging assembly is configured to provide a charge power to the laser transceiver assembly. The driving assembly is configured to drive the laser transceiver assembly to rotate. The wireless charging assembly and the driving assembly are respectively located at two opposite sides of the laser transceiver assembly.

Abstract: An improved eye tracking illumination system is disclosed. The system includes (i) an RGB laser device that is associated with a first collimating optic and (ii) an IR illumination device that is associated with a second collimating optic. The system also includes a DMA that has a MEMS mirror system. The DMA optically combines IR light and RGB light to generate combined light. The combined light is then directed towards a user's eye via a transport medium (e.g., a waveguide). One or more photodetector(s) are positioned to capture reflected light that is reflected off of the user's eye. The photodetectors include an IR detector configured to detect reflected IR light off of the user's eye in order to perform eye tracking.

Abstract: A wideband, radio-frequency localization system may estimate the one-dimensional, two-dimensional or three-dimensional position and trajectory of a static or moving object. These estimates may have a high spatial accuracy and low latency. The localization may be determined based on phase or amplitude of a wideband signal in each frequency band in a set of multiple frequency bands. The localization may be based on a single shot of measurements across a wide band of radio frequencies, without frequency hopping. The measurements of the wideband signal may be taken over time and over space at multiple receivers. The localization may be based on measurements taken while a backscatter node remains in a first reflective state or in a second reflective state, rather than when the backscatter node is transitioning between reflective states. In some cases, the localization achieves sub-centimeter spatial resolution in each of three spatial dimensions.

Abstract: A system and method for forming a range estimate for a target with a laser detection and ranging system. The system includes a laser transmitter and an array detector. The method includes: transmitting a plurality of laser pulses; for each transmitted laser pulse: detecting, with the array detector, a plurality of ladar return photons from the laser pulse, each detection producing an electrical pulse; identifying, for each of the electrical pulses, a time bin of a plurality of time bins corresponding to the laser pulse, within which the electrical pulse was produced; forming a one dimensional range histogram array having, for each of a subset of the plurality of bins, an element with a value equal to the number of electrical pulses produced in the array detector during a time interval corresponding to the bin; and forming an estimated range rate for the target.

Abstract: A wideband, radio-frequency localization system may estimate the one-dimensional, two-dimensional or three-dimensional position and trajectory of a static or moving object. These estimates may have a high spatial accuracy and low latency. The localization may be determined based on phase or amplitude of a wideband signal in each frequency band in a set of multiple frequency bands. The localization may be based on a single shot of measurements across a wide band of radio frequencies, without frequency hopping. The measurements of the wideband signal may be taken over time and over space at multiple receivers. The localization may be based on measurements taken while a backscatter node remains in a first reflective state or in a second reflective state, rather than when the backscatter node is transitioning between reflective states. In some cases, the localization achieves sub-centimeter spatial resolution in each of three spatial dimensions.

Abstract: A computer-implemented method of determining a relative velocity between a vehicle and an object. The method includes receiving sensor data generated by one or more sensors of the vehicle configured to sense an environment following a scan pattern. The method also includes obtaining, based on the sensor data, a point cloud frame. The point cloud frame comprises a plurality of points of depth data and a time at which the depth data was captured. Additionally, the method includes selecting two or more points of the scan pattern that overlap the object. The selected points are located on or near a two-dimensional surface corresponding to the object, and the depth data for two or more of the selected points are captured at different times. The method includes calculating the relative velocity between the vehicle and the object based on the depth data and capture times associated with the selected points.

Abstract: A method is disclosed of measuring a hollow object such as a pipe including temporarily attaching to that object a reference target support such as a stencil that supports a plurality of scannable reference targets. When scanning the object with a movable scanner, most conveniently a hand-held scanner, the reference targets provide a positional reference for the scanner. A reference target support that is attachable to or movable along a hollow object has a display face presenting and supporting a plurality of scannable reference targets. The display face can stand up from a surface of the object or can lie against a surface of the object. The reference target support and the scanner can be movable together along a pipe as an internal inspection pig.

Abstract: Systems (100) and methods (600) for acquiring data relating to an environment of interest. The methods comprise: receiving by a telescope (110) light scattered by an object within the environment; focusing a cone of light towards a spatial light modulator (112) which is placed a certain distance from the telescope on a telescope-focus surface; and deflecting a select amount of the cone of light by the spatial light modulator towards a photodiode array (114), whereby a sensitivity across the photodiode array is made uniform.

Abstract: A system and process for performing orthopedic surgery is provided that uses a patient's existing implant as a registration tool in an orthopedic surgical procedure. The systems and processes may be used with computer assisted systems or navigation systems to aid in the removal of bone, bone cement, or a bone prosthesis, typically a bone prosthesis used in hip replacement surgery, knee replacement surgery, and the like. The removal of the prosthesis may be done by conventional methods, with navigation systems, robotic assistance or articulating hand held systems. The removal of bone and/or bone cement may be performed with navigated systems, robotic systems, articulating hand-held systems and combinations thereof.

Abstract: A noncontact optical three-dimensional measuring device that includes a first projector, a first camera, a second projector, and a second camera; a processor electrically coupled to the first projector, the first camera, the second projector, and the second camera; and computer readable media which, when executed by the processor, causes the first digital signal to be collected at a first time and the second digital signal to be collected at a second time different than the first time and determines three-dimensional coordinates of a first point on the surface based at least in part on the first digital signal and the first distance and determines three-dimensional coordinates of a second point on the surface based at least in part on the second digital signal and the second distance.

Abstract: A method of imaging a scene includes generating a temporally varying optical intensity pattern from at least one continuous wave (CW) light beam. The method also includes illuminating at least one portion of the scene with the temporally varying optical intensity pattern so as to cause a photon to scatter or reflect off the at least one portion of the scene. The photon reflected or scatted from the at least one portion of the scene is detected using a single-photon detector. Based on the temporally varying optical intensity pattern and a time of flight of the photon detected, a distance between the single-photon detector and the at least one portion of the scene is estimated.

Abstract: A calibration structure for calibrating optical measuring devices is provided. The calibration structure includes a plurality of zones adjoining one another in a plane, wherein the zones adjoin one another along straight lines and/or curved lines and the calibration structure has both zones adjoining one another along straight lines and zones adjoining one another along curved lines, wherein the zones adjoining one another along straight lines or the zones adjoining one another along curved lines have respectively mutually different optical properties. Furthermore, a calibration method for calibrating the optical measuring devices by the calibration structure is provided.

Abstract: The present invention relates to a laser device for supporting work on a construction site and a laser beam detector for detecting light of a laser beam rotating around a rotation axis of a laser device. There is a need that the detector is able to identify the laser device which emitted the light that the detector detects. This can be achieved by a laser device comprising a laser unit configured to emit a laser beam; an optical element arranged to rotate the laser beam around a rotation axis; and a transmitter configured to transmit a communication signal over an interface to a receiver of a laser beam detector, wherein the communication signal provides information about a rotation pattern of the rotating laser beam.

Abstract: A method and system for determining the presence or absence of a part of an assembly within at least one user-defined, 3-D detection region within a work cell are provided. The system includes a 3-D or depth sensor having a field of view at the work cell. The sensor has a set of radiation sensing elements which detect reflected, projected radiation to obtain 3-D sensor data. A processor processes the sensor data from the sensor to obtain a 3-D graphic of the at least one detection region. A display displays the 3-D graphic from a viewpoint to determine the presence or absence of the part within the detection region.

Abstract: Some embodiments of the invention include a vehicle control system having: two GNSS receivers positioned fixedly in a known relationship with respect to one another on a vehicle, for receiving signals from navigation satellites, a computer unit for using the signals to form direction vectors, and generating instructions for steering the vehicle as a function of the direction vectors, wherein at least one retro-reflector is arranged in a predefined position with respect to the GNSS receivers on the vehicle, a geodetic measuring device is positioned in an immovable fashion at a known reference position in order to determine exact absolute positions of the retro-reflector, wherein the measuring device has a transmitter for transmitting the exact absolute positions to a receiver of the computer unit, and the computer unit is also designed to generate the instructions as a function of the exact absolute positions.

Abstract: A self-propelled construction machine includes machine frame that is laterally extendible to adjust a width of the machine frame. A frame lock can selectively lock and unlock the machine frame to permit the width adjustment. A controller includes a frame extension mode configured to steer at least one ground engaging unit to provide a lateral force to adjust the width of the machine frame as the machine is driven across the ground surface by the ground engaging units.

Abstract: A noncontact optical three-dimensional measuring device that includes a first projector, a first camera, a second projector, and a second camera; a processor electrically coupled to the first projector, the first camera, the second projector, and the second camera; and computer readable media which, when executed by the processor, causes the first digital signal to be collected at a first time and the second digital signal to be collected at a second time different than the first time and determines three-dimensional coordinates of a first point on the surface based at least in part on the first digital signal and the first distance and determines three-dimensional coordinates of a second point on the surface based at least in part on the second digital signal and the second distance.

Abstract: A laser scanner, in particular a safety laser scanner, in accordance with the operating principle of the time of flight process, comprising a light transmission unit having at least one light transmitter for transmitting a polarized transmitted light beam into a monitored zone; a light reception unit having at least one light receiver for detecting the polarization component of the light reflected in the monitored zone being orthogonal to the polarization direction of the transmitted light beam, and/or the polarization component of the light reflected in the monitored zone being parallel to the polarization direction of the transmitted light beam, and for generating a received signal corresponding to the detected orthogonal polarization component and/or the detected parallel polarization component; and an evaluation unit configured to evaluate the time development of the detected orthogonal polarization component and/or of the detected parallel polarization component.

Abstract: A method of calibration of a navigation and pointing system (10) including a navigation unit (11) integrally connected to a pointing device (12), the navigation unit being configured to measure the orientation of a navigation reference system (21), the pointing device (12) being configured to measure a signal in a pointing reference system (22). The calibration method includes the following steps: selecting a first planar surface (8) and a second planar surface (9); acquiring measurements via the system by directing the pointing direction towards the first planar surface (8), and respectively towards the second planar surface (9), according to a plurality of predetermined orientations; applying an algorithm for processing the measurements acquired at the previous step to extract therefrom the misalignment angles between the navigation reference system (21) and the pointing reference system (22).

Abstract: Method for measuring an extruded profile using a measuring apparatus, wherein the measuring apparatus is designed to produce and measure at least two laser light sections on a surface of the profile, which is being pulled through the measuring apparatus, by means of at least one laser light section sensor from a respective, different position around the profile, wherein the at least two laser light sections are situated essentially in one plane. By positioning at least two references and/or reference markers from the adjacent positions together with the extruded profile in a respective common measurement capture area, said references or reference markers are used for calibration of respective raw image of the at least one laser light section sensor. Thus, the calibrated raw image data are correctly mapped in a common coordinate system from the respective position.

Abstract: Some embodiments of the invention may relate to an optical surveying device having a base for setting up the surveying device and a targeting unit, which is rotatable in relation to the base about two axes, and which defines a target axis or targeting a target object to be surveyed. In some embodiments, the targeting unit has a first beam path for emitting optical radiation in the direction of the target object to be surveyed and a second beam path for receiving a component of the optical radiation, which is reflected from the target object, by way of an optoelectronic receiving element. In some embodiments, at least one of the beam paths, has an optical element, which is implemented having an optically transparent, deformable volume body, and which has at least one interface toward a medium having an optical index of refraction deviating from the volume body.

Abstract: A construction machine control system comprises a laser surveying instrument for projecting N-shaped beams in rotary irradiation, a construction machine operated within a predetermined range of the N-shaped beams, and an elevation angle detecting unit. The construction machine comprises a working mechanical unit for carrying out construction operation, a machine control device for controlling the working mechanical unit, and at least three beam detectors disposed at known positions with respect to reference position of the construction machine. The beam detectors detect the three fan beams and output result of photodetection. The elevation angle detecting unit obtains elevation angles of each of the beam detectors with respect to the laser surveying instrument based on result of photodetection of three fan beams from the beam detectors. The machine control device is configured to control tilting of the working mechanical unit based on the elevation angle obtained.

Abstract: An optical measurement apparatus comprises an optical system (100) having a receiving axis (115). The optical system (100) comprises a source (102) that generates a probe beam that is directed to a location to be measured (114). A detector (112) of the optical system receives a reflected beam from the location to be measured (114). The apparatus also comprises a processing resource that receives an output signal from the detector (112) and makes an assessment of a characteristic of the output signal in order to determine a degree of alignment of the location to be measured (114) with the receiving axis (115) of the optical system (100).

Abstract: Systems and methods for targeting a directed energy system are provided. A particular system includes a first laser and a second laser. The system also includes a scanning system coupled to the first laser and the second laser. The scanning system is adapted to movably direct the second laser in a pattern around a pointing location of the first laser.

Abstract: A device for measuring the position of at least one moving object in a three-dimensional grid. The device comprises: at least one optical head comprising an independent laser sources array outputting collimated laser beams, arranged about a central photodetector with a single sensitive cell; at least one movable base with two rotational degrees of freedom whereto said array is secured; and control electronics.

Abstract: A method and optical device measures the rotation of an object, including a light source emitting a collimated incident light beam, and a reflecting plane optical interface to be fastened to the object and forming a first reflected beam. The device includes a corner reflector fastened to the object, and having reflecting plane faces forming a second reflected beam, and a detection system capable of measuring the displacement ?1 of the first reflected beam, and the displacement ?2 of the second reflected beam. A processing system calculates, as a function of ?1 and of the distance D1 between the detection system and the reflecting plane optical interface, and of the measurement of ?2 and of the distance D2 between the detection system and the corner reflector, a measurement of the rotation ? of the object between an initial position and a measurement position.

Abstract: A scanner including: a transparent plate; a light emitting unit that emits light to an object on the transparent plate; a sensor to form an image of the object; a focusing lens unit that is arranged on a light path between the transparent plate and the sensor, to focus light from the object onto the sensor; and a controller to determine whether a foreign substance is disposed in the light path, using the image, calculates a position of the foreign substance, and corrects the image on the basis of the calculated position of the foreign substance.

Abstract: A method for acquiring signals in laser scanning microscopy, includes the steps of: moving a focused optical excitation beam relative to an object to be measured so that the focus point of the beam follows a predetermined path in the space of the object; and acquiring optical measurement signals along the path according to at least one acquisition parameter; characterized in that the path of the excitation beam is determined so as to substantially minimize the variations of the optical properties of at least one portion of the environments crossed by the excitation beam between consecutive acquisitions, and in that at least one acquisition parameter among the acquisition parameters is modulated during the movement of the excitation beam. A device for implementing the method is also described.

Abstract: A method and apparatus for bitstream modulation of an infrared light source used by an optical sensor in a stereoscopic projection system, combined with a bitstream filter on the receiver electronics.

Abstract: A degradation in throughput is prevented even in cases where it is necessary to reduce a pixel size during inspection according to a finer circuit pattern. In an inspection method and an inspection apparatus in which an inspected sample having a circuit pattern is irradiated with a charged particle beam to generate a signal, an image is obtained from the signal, and in which a defect of the circuit pattern is detected from the image, the inspection is performed while an inspected pixel size in a direction in which the charged particle beam is scanned relative to the inspected sample and an inspected pixel size in a stage moving direction are separately set. The stage is moved while the inspected sample is placed thereon.

Abstract: Tools and techniques for estimating elevations, including without limitation tools and techniques that employ mobile stations with laser detectors for receiving a beam emitted from a laser source and estimating an elevation of the mobile station based on the received beam. In some instances, a mobile station may be configured to identify, based on some or all of a variety of factors, a situation in which the elevation of the detector is likely to change to the extent that the slope of the emitter needs to be adjusted to account for this change in elevation. The mobile station may also be configured to inform the laser source that the slope of the emitted beam should be adjusted. In response, the laser source may adjust the slope of the emitted beam accordingly.

Abstract: A first method determines a position of a point of interest on a target object surface in a target object coordinate system using orientation and distance measurements of a pointing instrument in an instrument coordinate system. A second method determines an orientation of a pointing instrument in an instrument coordinate system for the instrument to be aligned with a point of interest on a target object surface having a target object coordinate system, wherein a position of the point of interest in the target object coordinate system is known. A third method controls orientation of a laser beam of a laser in an instrument coordinate system for the laser beam to trace an image on a target object surface having a target object coordinate system, wherein positions of points for the image on the surface of the target object in the target object coordinate system are known.

Abstract: Tools and techniques for estimating elevations, including without limitation tools and techniques that employ mobile stations with laser detectors for receiving a beam emitted from a laser source and estimating an elevation of the mobile station based on the received beam. In some instances, a mobile station may be configured to identify, based on some or all of a variety of factors, a situation in which the elevation of the detector is likely to change to the extent that the slope of the emitter needs to be adjusted to account for this change in elevation. The mobile station may also be configured to inform the laser source that the slope of the emitted beam should be adjusted. In response, the laser source may adjust the slope of the emitted beam accordingly.

Abstract: The present invention provides operators the ability to follow a predetermined path and achieve desired digging depth by watching steering and elevation indicators of just one system. The indicators are activated by data derived from the interception of signals generated by a single laser transmitter and a receiver array mounted on the machine. The system according to the present invention uses the multiple, tilted fan beams provided by the laser transmitter to calculate elevation angle and azimuth of the tool carried by machine.

Abstract: A laser measuring system, which comprises a laser rotary irradiation device for forming a laser reference plane by projecting a laser beam in rotary irradiation, and a photodetection device for performing position measurement by receiving the laser beam, wherein the laser rotary irradiation device comprises a laser beam emitter, an emission light amount adjusting means for adjusting light amount of the laser beam of the laser beam emitter, and a first communication means for performing communication with said photodetection device, and wherein the photodetection device comprises a photodetector for detecting the reference plane, a second communication means for performing communication to and from the laser rotary irradiation device, and a control unit for calculating whether a photodetection signal from the photodetector is within a predetermined range or not, wherein the first communication means transmits a laser beam emitting condition of the laser rotary irradiation device to the second communication mea

Abstract: One aspect of the invention relates to a laser ranging system. In this version of the invention, a guided missile is provided with laser that directs laser radiation in the general direction of a target that is subsequently reflected from the target back to the missile. A receiving lens is mounted on the missile that receives the reflected laser radiation. A ferrule containing optical fibers divided into a plurality of pixels that receive the reflected laser radiation from the receiving lens, wherein each pixel in the plurality of pixels is provided a different pointing angle by arranging the fibers within the pixel such that the centroid of the field of view of the fibers is different from the centroids of the field of views of the other fibers in the other pixels.

Abstract: A method, system and computer program product for determining an angle of incidence of a light beam illuminating a workpiece positioned on a stage are disclosed. A method for determining an angle of incidence of a light beam illuminating a workpiece positioned on a stage may include: positioning a calibration target on the stage with multiple different tilts; first determining an angle of incident of the light beam with respect to the calibration target with each tilt using a detector; mapping a response of the detector to a determined angle of incidence; and second determining the angle of incidence with respect to the workpiece based on a result of the mapping.

Abstract: A method serves to determine the 3D coordinates of an object. The 3D coordinates of a partial surface (6) of the object are determined by a 3D measuring device (3), which includes one or more detectors (4) and whose position is determined by a tracking system. The 3D coordinates of an adjacent partial surface (7) of the object are determined by the 3D measuring device (3). The 3D coordinates of an overlap region of he adjacent partial surfaces (6,7) are put together by a matching method. In doing so, an error function is determined and minimized iteratively. Furthermore, the error function of a detector (4) of the 3D measuring device (3) is determined.

Abstract: A multi-spectral sensor system and methods are disclosed. One aspect of the invention comprises a multi-spectral sensor system mountable to a mobile platform. The system may comprise an image capturing system, a first translation stage affixed to the image capturing system and a stationary optics assembly. The system may further comprise a motion controller configured to move the first translation stage and image capturing system across the stationary optics along a traveling direction opposite of a traveling direction of the mobile platform and at substantially the same rate as the mobile platform is moving during a stare operation.

Abstract: A beam detector includes a beam detection sensor to receive a light beam emitted from a light source of a light scanning unit and to generate a synchronous signal, a slit member having a slit formed therein to control a time to generate the synchronous signal of the beam detection sensor by adjusting an amount of the light beam received by the beam detection sensor, and a holder in which the slit member is installed. The slit is extended in a vertical direction and, a pair of surfaces form the slit and face each other, one of the pair of surfaces at which a scanned light beam arrives first is inclined in the vertical direction.

Abstract: An improved three-dimensional (3D) measuring apparatus for scanning an object and a measurement head of a measuring apparatus and a method for using the measuring apparatus for scanning an object.

Abstract: A multiple beam path surveying instrument is provided, which possesses an upper part that is rotatable about a vertical axis and which comprises a telescope body that can be swiveled about a tilt axis, with the vertical and tilt axes orthogonally intersecting at an intersection point S. At least two optical arrangements with optical beam paths are set up inside the telescope body. Driving and/or adjustment devices are provided for rotating the upper part about the vertical axis and the telescope body about the tilt axis. Further, measuring systems for determining the rotational angle of the upper part of the survey instrument about the vertical axis and the telescope body about the tilt axis are provided. A computer system may be used to evaluate the measurements, determine, display and/or record the measurement results, as well as to control the driving and adjustment devices for the telescope body and the upper part.

Abstract: A working position measuring system, comprising a rotary laser device for irradiating and rotating a laser beam and a photodetection sensor device for receiving the laser beam and for detecting a working position, wherein the rotary laser device comprises a laser projector for projecting at least two fan-shaped beams with at least one beam tilted, and the photodetection sensor device comprises at least one photodetection unit for receiving the fan-shaped beams and an arithmetic unit for calculating an elevation angle relative to the rotary laser device based on photodetection signals produced when the photodetection unit receives the light beam.

Abstract: Field-deployable spatial positioning or measurement systems are provided for improved versatility, reliability and performance. The spatial positioning or measurement systems use rotating laser fans or beams for positioning and measuring and include a system integrated field-deployable length standard that uses a reelable tape with positional indents. The systems further include the use of labyrinth seals at interface volumes between rotating laser heads and transmitter assemblies to prevent ingress of contaminants and allow for elimination of the use of rotary seals. Further, new dynamic leveling techniques are provided to plumb positional laser transmitter systems. Still further, strobe beam configurations are provided for improved near/far performance and a vertical mode sensing scheme that allows switching to measuring tall structures when needed.

Abstract: In a laser measurement apparatus capable of measuring a moving object or a designated object to be measured by tracking an object to be tracked and detecting the position of the tracked object as needed, optical signal processing units 103 through 105 output laser beams having different wavelengths via a common optical path A toward a corner cube 100 attached to an object to be measured, and detect the laser beams being reflected on the corner cube 100. A control unit 102 controls motors 110, 111 so that the laser beams return to a predetermined position of an optical position sensitive detector 117 of an optical signal processing unit 103, by which the direction of a reflecting mirror 112 is controlled so that the laser beams track the object. The control unit 102 computes the distance, shape, position, speed etc.

Abstract: A method and apparatus which enables an individual user to determine corners and other points of interest in a construction site layout. Basic trigonometric calculations are made based on a dimensioned drawing which enables corners or other points of interest to be located by measurement to a plurality of known locations which preferably lie away from the working are of the construction site. The worker or workers then take these measurements to the site and measures the calculated distances from the know locations to determine the location of the points of interest.