Patent ID: 6091487
Filing Date: 2000-07-18
Classification: G01C,G01S

Abstract:
A laser transmitter comprising:a laser detection module operative to produce a reflected laser beam signal;an optical system arranged to generate a reference laser beam selectively in one of a search mode and a target dither mode and to direct a reflected laser beam to said laser detection module, wherein said optical system defines a rotational axis, said reference beam projects radially from said rotational axis, said search mode is characterized by movement of the reference beam through a rotational arc defined about said rotational axis, and wherein said target dither mode is characterized by movement of said reference beam through a dither zone occupying a portion of said rotational arc; anda controller programmed toproduce selectively one of a target-sighted signal and a target-missing signal, wherein said target-sighted signal is produced in response to detection of said reflected laser beam,produce a rotary position signal indicative of a position said reference beam relative to said rotational arc,identify a target position based upon said reflected laser beam signal and said rotary position signal,establish said dither zone about said target position, wherein said dither zone occupies a portion of said rotational arc and is characterized by a dither range,move said reference beam in said target dither mode, wherein said target dither mode is characterized by reciprocative movement of said reference beam only through said dither zone,change a magnitude of said dither range in response to said target-sighted signal, andmaintain a magnitude of said dither range substantially constant in response to said target-missing signal.