Arcsecond, Inc.

Rick Slater

Timothy Pratt

Thomas M Hedges

Michael J Sobel

Scott C Casteel

Sean M Beliveau

Donald Todd

Thomas Cuff

Eric J Lundberg

Yvan J Beliveau

Edmund S Pendleton

Edward R Barrientos

Tom M Hedges

An improved, low-cost optical transmitter and method useful in a three-dimensional measurement system wherein a plurality of operational parameters of said transmitter are calibrated during manufacture/assembly process to generate unique calibration data for each optical transmitter including data defining angles of each transmitter's first and second radiant fan beams and the angle between the beams when the transmitter is leveled for operation in the system and wherein a detector/receiver in the system distinguishes between radiant beams from a plurality of individual transmitters operable within a given measurement field as a function of the selectively alterable rotational velocity calibration data for each of said transmitters and wherein said angular calibration data for each transmitter is operationally available to each detector/receiver operable in the system.

Low cost transmitter with calibration means for use in position measurement systems

An improved low cost theodolite position measurement system and process which is particularly useful in enabling a single operator to conveniently set up the system and calculate elevation (el) and azimuth (az) angle data. Only a single optical transmitter is positioned within a predetermined workspace thus significantly decreasing equipment costs and setup time. The single transmitter is positioned and leveled at a predetermined point in the workspace. In operation the single rotatably mounted transmitter head illuminates the workspace volume with a pair of spaced apart precalibrated fan beams which sweep the space and a periodically emitted reference strobe pulse. At least one optical receiver is selectively positionable within said workspace so that during each revolution of said single transmitter head said receiver receives a first position strike and a second position strike of said fan beams. To determine elevation angle data, tracker logic means responsive to said receiver determines a first tie interval separation between receiving said first position strike and said second position strike and calculation means for converting said first time separation interval into an elevation angle data. To determine an azimuth angle data said receiver receives a strobe pulse and a fan beam position strike, both of which are repeatedly transmitted with a known periodicity, determining a measure of time separation related to the strobe pulse and the position strike, and converting the measure of time separation into the azimuth angle data utilizing the known periodicity.

Low cost 2D position measurement system and method

An improved receiver for use in a robotic theodolite spatial positioning apparatus that allows a single user to determine elevation and azimuth angle data. To determine elevation angle of the receiver, the receiver has a sensor that receives a first position signal and a second position signal emitted from an optical transmitter. The receiver outputs a first and a second receive signal. A calculator in the receiver determines the first interval time separation between the first and second receive signals, converts the first time interval separation into elevation angle data and outputs the elevation angle data. A display in the receiver receives and displays the elevation angle data. The receiver is selectively positionable within a workspace. Determination of azimuth angle of the receiver is made by receiving a strobe pulse, determining the periodicity of the pulse and comparing the periodicity with transmitter calibration information stored in the receiver, and converting the measure of time separation into azimuth angle data. The display in the receiver receives and displays the azimuth angle data. Additionally, the user can select desired azimuth and/or elevation angles, and the display can guide the user to the desired location.

Apparatus and method for determining position

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Reston, VA, United States of America

Rick Slater