Projects‎ > ‎

Meteors

Meteors are small pieces of interplanetary debris burning up as they enter our atmosphere. More detailed information can be found on Wikipedia and on the website of the International Meteor Organisation.

At night, meteors may be visible to the human eye as shooting stars. Using radio techniques, meteors can be observed 24/7. The Belgian Institute for Space Aeronomy (BISA) exploits a radio meteor detection network using forward scattering methods. The network is known as BRAMS (Belgian RAdio Meteor Stations) and consists of one radio transmitter located at Dourbes, and approximately 30 receiving stations spread out over the country. The stations operate autonomously and upload their recorded data to a central server at BISA. Data from all stations are publicly available to registered users through the BRAMS website.

Meteor detection 

The files available for download from the BRAMS website contain the complete signal recorded at the receiving stations. Meteor signatures are present in the data but are not extracted or marked as such. For us to be able to count or otherwise analyse meteors, we must identify the meteors in the data. This process is called meteor detection, and can be performed in many different ways. We implemented one approach, click here for details.

Looking at data from the BRAMS station at Uccle – known as BEUCCL – we noticed that running the meteor detection algorithm resulted in many false positives: the algorithm identifying meteors when there are none. We conducted a sensitivity analysis with respect to the threshold value and based on that increased the threshold from its default value of 0.025 to 0.050. The sensitivity analysis is documented here.

The 2015 Quadrantids meteor shower

The Quadrantids are a meteor shower returning annually in early January. We used radio observations from the Uccle station of the BRAMS network to study the 2015 Quadrantids. All data collected at this station on 3 and 4 January 2015 were downloaded using a script, automatically fetching all 576 files totalling 1.8 GB of data. The meteor detection method referred to above was applied to this data set using a threshold value of 0.05. For this 48-hour period, a total of 763 meteors are detected with a peak hourly rate of 62 meteors between roughly 2 am and 3 am on the morning of the 4th of January. Click here for more details.

The spectrograms for these 576 files with meteor detections marked by red lines are available in an album on flickr.