This is a sensor with a sensitive
element made from a piezoelectric material whose electrical properties
vary according to the pressure exerted on the actual sensor. This
sensor sends an output voltage which is proportional to the pressure
or the vibrations to which the sensitive element is subjected.
Coriolis Force
The Coriolis force is an apparante
force which is exerted on a moving object in a rotary system. This
force is linked to the acceleration of the objected caused by the
rotation. For example, if a line were drawn towards the centre of
a stationary wheel which then starts to rotate, an observer, unaware
of the rotation, would notice this effeact as an apparent force
exerted diagonally in relation to the line. This force is the cause of the movement
of sea currents and winds in relation to the Earth which is rotating.
It dominates the progress of atmospheric currents, producing anti-clockwise
flows in the northern hemisphere and clockwise flows in the southern
hemisphere.
GPS (Global Positioning System)
The GPS (Global Positioning System)
is a constellation of satellites which orbit the Earth transmitting
information concerning time and position for every place on the
earth, 24 hours a day.This information can be received or used
by a special GPS receiver: the aim of the system is to provide any
user with the possibility of determining their position on the earth's
surface. The constellation of GPS satellites consists
of 24 satellites arranged in 6 orbital places which are at 60 degrees
to the equator and an average distance of 20,000 km and each orbital
period takes around 12 hours. The system has been developed for military
purposes by the American Ministry of Defence and guarantees a global
and continuous positioning service; a part of the system has also
been dedicated to civilian use. Three satellites are needed in order to
detect a two dimension position (longitude and latitude), whilst
four satellites give altitude information as well.