Patent ID: 6057777
Filing Date: 2000-05-02
Classification: B66C

Abstract:
A spatial positioning system for determining the linear position of a movable object along a selected axis, comprising:a target positioned at a location aligned with the selected axis;a broad beam optical energy emitter mounted on the movable object and directed at the target;an optical energy receiver mounted on the movable object and aligned to receive optical energy reflected by the target, the optical energy detector generating a receive signal indicating reception of the optical energy;a time of flight circuit coupled to the emitter and receiver and generating a flight time signal indicating the elapsed time from emission of the optical energy to reception of reflected optical energy; anda control circuit coupled to monitor the flight time signal and output a position signal indicating position of the movable object with respect to the target wherein the receive signal comprises a first signal indicating when the received power is greater than a preselected threshold and a second signal delayed from the first signal by an amount indicating the power of the received signal.