Abstract: There is disclosed methods and apparatus for compensated measurement of angular displacement within an instrument (600), such as a total station. Improved and compensated measurement of angular displacement is obtained by using a combination of e.g. an angular resolver (145) and an inertial sensor (645). A compensated angular position measurement is produced by combining at least portions of the output signals obtained from the angular resolver and the inertial sensor, respectively.

Abstract: A surveying instrument performs tracking of a target by controlling an orientation of a measuring unit relative to the target in two different angular directions. The control in one angular direction is based on detected light intensities which are modulated according to a first time pattern, and control of the orientation in the other angular direction is based on detected light intensities modulated according to a second time pattern just different from the first time pattern.

Abstract: An absolute optical encoder apparatus for measuring an absolute position comprises an optical disk or scale element (100) having both incremental and absolute code tracks formed thereon. In the embodiment, a photoemitter light source (110, 111) illuminates the tracks onto a CCD area array sensor (115, 116) such that an image is formed from a pixel matrix having of rows and columns. Two detector line rows (410, 420) of the pixel matrix are each read out from the portion of the matrix comprising the incremental and absolute code tracks respectively. Inaccurate mounting of the disk or scale element can cause fluctuations in the period of the code tracks resulting from the rotation of the disk or movement of the scale element. The mounting inaccuracies are compensated for either by matching the spatial frequency by dynamically changing row of detector line read from the incremental image of the code track or by altering the numerical value of the pattern period used in the Fourier phase algorithm.

Abstract: A method for determining, in relation to a surveying instrument, target coordinates of a point of interest, or target, identified in two images captured by a camera in the surveying instrument. The method comprises determining coordinates of the surveying instrument, capturing a first image using the camera in the first camera position; identifying, in the first image, an object point associated with the target; measuring first image coordinates of the object point in the first image; rotating the surveying instrument around the horizontal axis and the vertical axis in order to position the camera in a second camera position; capturing a second image using the camera in the second camera position; identifying, in the second image, the object point identified in the first image; measuring second image coordinates of the object point in the second image; and determining the coordinates of the target in relation to the surveying instrument.

Abstract: An electro optic distance measurement apparatus using time of flight measurements and a method therefore are provided for determining a distance to a target of two or more targets located along a common line of sight from the distance measurement apparatus. Approximate distances to the two or more targets are determined by means of the distance measurement apparatus, one of the two or more targets is selected, and an accurate distance to the selected target is determined by means of the distance measurement apparatus.

Abstract: The invention relates to a method and device for contactless or touch-free measurement of a tool by imaging. A processor makes calculations based on image points on the tool, imaged onto an imaging area. Optics present the image of the image points on the tool on the imaging area. The processor calculates the momentary position and/or orientation along at least one axis of the tool making use of the image points. A number of measuring markers have predetermined mutual positions and are on the tool. Each measuring marker comprises at least one measuring point. At least one of the points is identifiable. Each measuring marker to be used as position and/or orientation indicator has a size making it restorable by the processor even if a part of it on the tool is obscured from the image area, for example by dust.

Abstract: The invention relates to a method of operating a surveying instrument (10) placed in a orthogonal XYZ-system at (0,0,0) having a movable unit (20), said instrument defining a sight line (128) that is controllably rotatable around a first axis (50), essentially horizontal, and around a second axis (90), essentially vertical, wherein said second axis (90) may be inaccurately positioned so that it deviates from a true vertical axis, and said first axis (50) may deviate from being orthogonal to the second axis (90); the method comprising the steps of determining at least one of the following group of errors relating to the instrument and/or its location: a) a trunnion axis error T as a function of the deviation from 90 degrees between the first axis (50) and the second axis; b) a horizontal collimation error CH, being the deviation between the sight line (128) and the perpendicular angle as related to the first axis (50); and c) a total plumb error defined by components, PI and PII, being two separate angular val

Abstract: A surveying instrument and method determine a duration of a measuring period for obtaining readings of angle values of an angle measuring system in dependence of readings of an error signal produced by a tracking system. It is thus possible to determine a value of the angle represented by the readings of the angle signal with a desired accuracy in the presence of air turbulence wherein the measuring period is shorter at low degrees of air turbulence and longer at higher degrees of air turbulence.

Abstract: The invention relates to an electronic distance measuring apparatus for surveying, e.g. for measuring the distance from the apparatus to an object. The apparatus comprises: a) an objective lens (101), defining an optical axis (OA), b) at least two sources (111, 112) of structured light for transmitting beams (?1, ?2) of separate wavelengths towards said object, said beams on reflection from said object received by the objective lens (101), (c) at least two receivers (141, 142) arranged outside a beam path (109) as defined by the objective lens (101), and adapted to receive said received beams (?1, ?2) of structured light.

Abstract: A surveying instrument performs tracking of a target by controlling an orientation of a measuring unit relative to the target in two different angular directions. The control in one angular direction is based on detected light intensities which are modulated according to a first time pattern, and control of the orientation in the other angular direction is based on detected light intensities modulated according to a second time pattern just different from the first time pattern.

Abstract: A surveying instrument and method determine a duration of a measuring period for obtaining readings of angle values of an angle measuring system in dependence of readings of an error signal produced by a tracking system. It is thus possible to determine a value of the angle represented by the readings of the angle signal with a desired accuracy in the presence of air turbulence wherein the measuring period is shorter at low degrees of air turbulence and longer at higher degrees of air turbulence.

Abstract: A device and method for determining the position for a working part of a machine with a position-determining apparatus is disclosed. A detector is placed at a defined place on the machine to determine the position in a fixed coordinate system. A positional relationship device determines the positional relationship of the working part in relation to the detector in a machine-based coordinate system. A calculating device calculates, with signals from the position-determining apparatus and the positional relationship device, the position of the working part in the fixed coordinate system. The position-determining apparatus comprises an inclination- and orientation-measuring device that measures the instantaneous position and orientation of the position of the machine in the fixed coordinate system.

Abstract: The invention relates to a device and to a method for determining the position for a working part of a tool on a working machine with a position-determining apparatus (2, 4, 5, 6; 2, 4a, 4b, 5, 6?; 31, 33, 49, 50, 51, 1?,53). At least one detector equipment (4, 5, 6; 4a, 4b, 5, 6?; 31, 33; 49, 50, 51, 53) is placed at a defined place on the working machine (3; 52) in order to determine the position of this position in a fixed coordinate system. At least one positional relationship device (11) determines the positional relation of the working part in relation to the detector equipment in a machine-based coordinate system. A calculating device (20) calculates, with signals from the position-determining apparatus and the positional relationship device, the position of the working part in the fixed coordinate system.