Meteor and aircraft detection — The use of electromagnetic waves for space observation

Cédric Willemin

The French military radar GRAVES emits electromagnetic waves consistently at a frequency of 143.05MHz. These waves propagate in the air and are reflected by electrically conductive objects. If the object is moving, the reflected frequency will change. This effect is known as the Doppler shift.

The aim of this project was to extend the technique often used in military operations to a civil application, focused on astronomy. In the study, reflected waves were received by an antenna positioned on the roof at the Gymnase de la rue des Alpes, in Biel, Switzerland. The reflected signal was thereafter transmitted to a computer which displayed the Doppler shift graphically.

Results proved that the detection technique is very versatile as it can identify signals reflected by aircrafts, satellites like the International Space Station, and meteors. Since these objects are moving with very different speeds, the induced Doppler shifts are highly contrasted, which makes them easy to distinguish. Numerous concrete objects were identified in the study, from the meteorite swarm of the Perseids to the International Space Station (ISS).