There is a need for an inexpensive
altimeter to facilitate the landing of small, non-commercial seaplanes on
lakes. Most small non-commercial
airplanes are equipped with barometric altimeters. In order to obtain accurate readings, these altimeters must
be calibrated in reference to the air pressure at a landing site. Since this can only be accomplished
when there is a radio tower located in the landing site vicinity, with an
operator who has the tools necessary to read atmospheric pressure, a barometric
altimeter is not able to provide accurate readings for bush pilots landing in
remote locations.
There are other options available
to determine altitude in regions where barometric altimeters are not
feasible. Some alternatives
include laser and radio rangefinder devices. Laser rangefinders are very
accurate, even over distances of 400m. Commercial laser altimeters are
available for approximately $3500 USD [2]. Using Radio technology for altimeters is the oldest and one
of the most common methods in aviation and research today. Radio altimeters are
extremely accurate, and can operate under hugely ranging temperatures and
atmospheric conditions. However,
they are also highly expensive.
Both of these instruments are simply too costly for many pilots to
justify their purchase.
In most situations, it is possible
for bush pilots to land by gauging the distance to ground with their eyes. However, when landing on a lake on a
calm day it is difficult to gauge where the surface of the water is, due to the
waterıs high reflectivity. The
method currently employed to aid pilots in landing is to throw an item from the
window of the plane in order to see the ripples on the lake [1].
The aim of this project is to determine the feasibility of employing a sonic ranging device as an altimeter. This altimeter should have a range of 0-40 m, with an accuracy of 10cm [1].