Abstract: A process for calibrating and correcting errors in laser measurement systems in situ, either remotely over the Internet or where the laser measurement system is physically located. In one embodiment, a number of targets are arrayed around the scanner and read by the software of a system. The laser scanner is rotated 180 degrees and the positions of the targets are read again. A correction factor is determined by calculation and displayed to show the expected improvement in accuracy of the laser measurement system. In a second embodiment, the laser scanner is positioned under a vehicle with targets at reference positions for which the measurements are known. The scanner readings are checked against the known values and a correction factor developed. This could be applied on a one-time basis or it can be programmed in the host computer where evaluation and compensation occur automatically.

Abstract: A laser measurement system indicates the difference between an actual position of a vehicle frame reference point on a vehicle frame and a normal position employing a rotating laser scanner; an electro-optical detector and a host computer. A positioning arrangement is also provided for positioning the electro-optical detector at a known distance from the reference point. In operation, the host computer queries the scanner and detector via a communication link, calculates the actual position of the reference point, and displays the difference between the position of the vehicle reference point on the vehicle frame and the normal position.

Abstract: A device is disclosed for sensing information relating to the orientation of a selected direction or plane with respect to the horizontal. In one embodiment, the invention comprises a housing (40), a vial (70) mounting in the housing, a source of electromagnetic radiation (62, 64), sensors (66, 68) and associated electronic circuitry, and a rail (12) for positioning the housing. The vial is elongated along a central longitudinal axis and is partially filled with liquid (72) to form a bubble (74) in the vial. The source of radiation is positioned in a housing plane to one side of the vial such that radiation passes through the vial and forms a shadow of the bubble on the other side of the vial. The shadow is detected by the sensors, and the associated electronic circuitry produces an output signal having a characteristic related to the bubble position along the longitudinal axis.