Patent ID: 8780331
Filing Date: 2014-07-15
Classification: G01S

Abstract:
1. An evaluation device for path length measurement, configured to evaluate a measured signal which represents an intensity of a sequence of pulses of electromagnetic radiation, as a function of time after the sequence has covered a path length to be measured, the sequence of pulses having a repetition rate, wherein the evaluation device is configured to evaluate a first component of the measured signal, which first component oscillates with a first frequency, and a second component of the measured signal, which second component oscillates with a second frequency that is greater than the first frequency, and wherein the evaluation device further comprises an evaluation logic which is configured to determine a first estimate for the path length based on an evaluation of both the first component of the measured signal and the second component of the measured signal, and to determine an estimate of the path length which is refined compared to the first estimate based on an evaluation of the second component of the measured signal wherein the evaluation device is configured to measure a first phase difference associated with the first component of the measured signal with a resolution of 2×π×p/n, such that the first estimate for the path length a oximates the ath length inaccuracy which is less than a quotient of a speed of light and of the second frequency, wherein the first frequency is equal to p times the repetition rate and the second frequency is equal to n times the repetition rate, with p and n being integer numbers.