This method is different from the traditional surveying instrument method of measuring phase shifts by comparing the incoming wavelength with the phase of the reflected light. Any solid object will reflect back a certain percentage of the emitted light energy - it need only be small for our sensitive detector to pick it up. We measure the time it takes a laser pulse to travel to the target and back with a precision, crystal-controlled time base. Knowing the speed of light, we then calculate the distance traveled. To increase accuracy, the LTI laser measures as many as sixty pulses, utilizing a least squares method of determining the range.
Sophisticated error trapping algorithms are in place to ensure a reliable reading.