초록 ▼

An electronic distance meter comprises an integrated circuit from a GPS navigation receiver having a local pseudo-random number code generator for code demodulation that is connected to modulate either a polychromatic or a monochromatic light source. An optical system focuses the light on a distant

An electronic distance meter comprises an integrated circuit from a GPS navigation receiver having a local pseudo-random number code generator for code demodulation that is connected to modulate either a polychromatic or a monochromatic light source. An optical system focuses the light on a distant target with an unknown range. Reflections from the distant target are focused on a light detector that produces a phase-delayed copy of the original pseudo-random number code. The time-of-flight to and back from the distant target is a function of the distance. The GPS receiver integrated circuit computes the range based on the code-phase delay to a precision better than one centimeter. The position of a remote target can be triangulated from several electronic distance meters each having known positions, e.g., determined by included GPS navigation receivers. Conversely, the position of a single electronic distance meter can be determined by triangulation by ranging to several remote targets each having known positions.

대표청구항 ▼

[ What is claimed is:] [1.] An electronic distance meter (EDM), comprising:a first light emitter providing for the illumination of a first distant target with a first beam of light;a first light detector providing for the reception and detection of light reflected from said first distant target;a sa

[ What is claimed is:] [1.] An electronic distance meter (EDM), comprising:a first light emitter providing for the illumination of a first distant target with a first beam of light;a first light detector providing for the reception and detection of light reflected from said first distant target;a satellite navigation receiver connected to provide a one-pulse-per-second (1-PPS) output for a derivative clock synchronized to an atomic clock in conventional orbiting global positioning system (GPS) satellites, and outputting a precision timing base;a first modulator connected to the first light emitter providing for modulation of said first beam of light with a first pseudo-random number (PRN) modulation signal having a first characteristic PRN code sequence; anda first digital signal processor (DSP) connected to receive both said precision timing base and a first detected-light input signal from the first light detector and having range computer means for code correlation and code-phase locking onto said first detected-light input signal and for determining a first distance to said first target based on the difference in phase of said first detected-light input signal and said first PRN modulation signal, given the speed of light through an interim medium to said target object;wherein, the first modulator drives the first light emitter according to a pseudo-random number (PRN) code sequence that mimics one of the PRN codes transmitted by conventional orbiting global positioning system (GPS) satellites and includes at least one of a coarse acquisition (C/A) code having a code length of 1023 chips transmitted at a rate of 1.023 Mbits/sec., and a precision (P) code having a code length of 5.sup.10 chips transmitted at a rate of 10.23 Mbits/sec; andwherein, the first digital signal processor (DSP) resolves a time-of-flight delay "t" to said first distant target to within tens of picoseconds.