Patent ID: 7336346
Filing Date: 2008-02-26
Classification: G01S

Abstract:
1. A distance measuring device comprising a reference signal oscillator that generates a reference signal, a light source that emits a distance measuring light modulated based on the reference signal, a light transmitting optical system that transmits a distance measuring light, a light receiving optical system that receives a distance measuring light reflected from a target, a light receiving element that converts a received distance measuring light to a distance measuring signal, a sampling unit that samples the distance measuring signal, a quantization unit that quantizes the sampled distance measuring signal, a storage unit that stores quantized distance measuring signal data, and an operation unit that calculates a distance based on a phase difference between the reference signal and distance measuring signal, wherein the operation unit calculates amplitude of each frequency of the distance measuring signal based on the distance measuring signal data, determines frequency distribution of the amplitude, and ends sampling to calculate a distance when the number of pieces of the distance measuring signal data is equal to or more than a minimum required number and it can be estimated, from the frequency distribution of the amplitude, that variance of the distance is equal to or less than a predetermined value.