COHERENT-BURST LASER RANGING - DECOUPLING RESOLUTION AND UNAMBIGUOUS RANGE

A novel signal encoding and decoding method for laser ranging is propo sed and experimentally demonstrated. The coherent-burst method uses a quasi-continuous interrupted burst of modulated laser radiation to ach ieve high-precision ranging at all distances. Both time of flight and phase shift are determined based on modulation provides high absolute precision, while measured temporal delay from transmission to receptio n eliminates potential uncertainty from aliasing. The method is demons trated with low-power diode lasers that can be modulated at frequencie s in excess of 250 MHz. (C) 1997 Optical Society of America.