Implementation of an advanced laser ranging concept

The design and performance features of a pulsed laser diode rangefinder (PLR) which has been operated with mm-accuracy in a prototype configuration are described. The device was developed of rendezvous and docking maneuvers, alignment, position control, contour and vibration monitoring of large space structures, in-flight control of free-flying platforms and for robotic vision for automated repair and service systems. Using a 5 nsec pulse and a 905 nm wavelength, the PLR system measures distance by the time-of-flight method. The laser pulses are fed to the sensor head through optic fibers. Return flashes are carried to an avalanche photodiode by optic fibers. Picosec tuning is achieved by applying a modified dual-slope interpolation procedure to quantize the time measurments with respect to a quartz clock.