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US 6,144,308 AGranted
Tilt compensation apparatus and method for use with a monopod mounted laser range finder apparatus
AssigneeLaser Technology, Inc.
InventorJeremy G. Dunne
Life of this patent
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AssigneeLaser Technology, Inc.
InventorJeremy G. Dunne
Estimating the term…
A tilt compensation method, circuit and apparatus utilizes a two axis tilt sensor or two single axis tilt sensors for alerting, a user and/or compensating a surveying instrument for off vertical alignment above a reference point when the instrument support is free to move about the reference point, e.g., when mounted on a monopod support. The sensor comprises a cell having a central electrode and four peripheral electrodes spaced 90 degrees apart around the central electrode. Fluid in the cell chamber changes the conductance of the electrodes with reference to the central electrode. The cell is mounted to the support or to the instrument itself. A microprocessor preferably provides a square wave drive signal selectively to alternate pairs of the opposing electrodes through tristate buffers while at the same time the microprocessor provides a channel select signal to the gate of the tristate buffers to float the idle electrodes. The signal on the central electrode is fed to an ADC and then to the microprocessor. The microprocessor preferably produces an alarm signal if the tilt is more than a user determined value. The microprocessor may use the sensed tilt magnitude and direction to automatically calculate corrections and compensate the distance measurement made by the distance measuring device such as a laser range finder for the off vertical orientation of the range finder.
A tilt sensor drive circuit for use with a tilt sensor arrangement having two pairs of opposing peripheral electrodes each pair spaced equally apart about a central signal output electrode to provide an output representative of tilt of said sensor arrangement from a horizontal orientation, said circuit comprising:
A tilt alarm apparatus for indicating when a member exceeds a predetermined tilt variance from a vertical orientation comprising:
A tilt alarm module adapted to be fastened to a monopod support for a distance measuring instrument in which the alarm module senses and indicates when the monopod support exceeds a predetermined inclination angle from a vertical orientation, said module comprising:
A laser based surveying instrument comprising:
A method for alerting a surveying instrument operator to approaching unacceptable off vertical alignment conditions of the instrument when the instrument is mounted on a one dimensional support comprising the steps of:
Dependencies are inferred from the claim text.