Introduction - SPECIAL ACCESSORIES

Piezoelectric sensor

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.