Patent ID: 6288775
Filing Date: 2001-09-11
Classification: G01S

Abstract:
A lightwave distance measuring apparatus having a coaxial light-transmitting/receiving type optical system, said apparatus comprising;light-transmitting means for transmitting pulsed light toward an object;light-receiving means for receiving reflected pulsed light reflected by said object;reference beam light transmitting means for transmitting a reference beam toward said light-receiving means;light switch for directing a selected one of said reflected pulsed light and said reference beam toward said light-receiving means;a time measuring section for measuring a first period of time from when said pulsed light is transmitted until said pulsed light is received and a second period of time from transmission by said reference beam until said reference beam is received;a distance measuring section for determining a distance to said object from said measured first and second periods of time and without requiring timed coincidence between plural ones of the reflected pulsed light; anda pulse number detecting section for detecting whether the number of pulses of light received by said light-receiving means in response to one transmitting pulsed light is one or more, andwherein, when a plurality of pulses of received light are counted by said pulse number detecting section, said distance measuring section is kept from carrying out distance measurement based on said received pulsed light.