Line-of-sight Propagation As A Prerequisite For Radio Distance Measurements
Travel time of radio waves between transmitters and receivers can be measured disregarding the type of propagation. But, generally, travel time only then represents the distance between transmitter and receiver, when line of sight propagation is the basis for the measurement. This applies as well to RADAR, to Real Time Locating and to LIDAR.
This rules: Travel time measurements for determining the distance between pairs of transmitters and receivers generally require line of sight propagation for proper results. Whereas the desire to have just any type of propagation to enable communication may suffice, this does never coincide with the requirement to have strictly line of sight at least temporarily as the means to obtain properly measured distances. However, the travel time measurement may be always biased by multi-path propagation including line of sight propagation as well as non line of sight propagation in any random share. A qualified system for measuring the distance between transmitters and receivers must take this phenomenon into account. Thus filtering signals traveling along various paths makes the approach either operationally sound or just tediously irritating.
Read more about this topic: Line-of-sight Propagation
Famous quotes containing the words prerequisite, radio and/or distance:
“You have to penetrate a woman’s defenses. Getting into her head is a prerequisite to getting into her body.”
—Bob Guccione (b. 1930)
“All radio is dead. Which means that these tape recordings I’m making are for the sake of future history. If any.”
—Barré Lyndon (1896–1972)
“A solitary traveler whom we saw perambulating in the distance loomed like a giant. He appeared to walk slouchingly, as if held up from above by straps under his shoulders, as much as supported by the plain below. Men and boys would have appeared alike at a little distance, there being no object by which to measure them. Indeed, to an inlander, the Cape landscape is a constant mirage.”
—Henry David Thoreau (1817–1862)