3D Time-of-flight distance measurement with custom - Universität ...

INTRODUCTION 1
1. Introduction
One can find time-of-flight measurement systems in nature’s navigation solutions
for dolphins and bats, which use this sensor system for both navigation and object
tracking (hunting). Moreover, humans have also used TOF techniques since a long
time, for example by dropping rocks down deep holes and waiting for the echo or
by trying to estimate the distance of a lightning discharge by evaluating the time
delay between the lightning and the associated thunder. These TOF methods are
based on the propagation time of sound [STR].
Figure 1.1 Galileo Galilei’s experiment of the early 17 th century to prove that light
travels through free space rather than existing instantaneously [HOF].
The actual pioneer in optical time-of-flight measurement was Galileo Galilei, who
was probably the first to imagine light as a kind of active event, something that
travels through free space rather than existing instantaneously. He also tried to
prove his idea by a simple experiment, described in one of his “Discorsi” that he
wrote under house arrest in the early 17 th century. In the dark of night he placed two
men (A and B) onto two neighboring hills, about 1 kilometer away from each other.
Each of them carried a lantern, covered by their hands, so that one could not see
the other’s lantern light initially. The experiment started with person A uncovering
his lantern and waiting for B to uncover his lantern as well, as soon as he saw the