sky with stars
sky with stars


1 January 2023
Project type

In the “Astrometrix” project, the Radboud Radio Lab aims to import radio astronomical techniques into digital signal processing world.

Radio astronomers already used low-frequency radio antennas (LOFAR - AUGER) to localize air showers from ultra-high energy cosmic rays and to precisely measure their properties. Air showers are particle avalanches that are generated when a high-energy elementary particle accelerated in the cosmos collides with an air molecule in our atmosphere. The resulting particle avalanche rushes with the speed of light through the atmosphere and transmits radio pulses lasting only some ten nanoseconds. Measuring the radio emission from air showers, astronomers can now determine the nature of the original particle with relatively high precision.

In particular Dutch astronomers used the innovative LOFAR radio telescope in the Netherlands – a giant phased array – and a network of 125 self-sufficient smart radio antennas that they installed in the Argentinian pampa to track cosmic rays. Astronomers can actually localize radio sources to within a fraction of a wavelength – i.e., anywhere from millimeters to centimeters to meters depending on the radio frequency. This concept is scalable and can be used to measure accurate locations over distances from meters to thousands of kilometers, depending on the power of the transmitters and the separation of the antennas.

With a compact test setup measuring meters to a side, we can perform experiments with this technique indoors at Huygens. However, this brings with it its own set of challenges: the proximity of structures such as walls and cabinets interferes with the radio waves and causes multipath effects in the phase measurements. Dealing with these influences requires some creative thinking!

Within Astrometrix, we are looking for students specializing in signal processing, design of algorithms, electronic engineering or mechanical engineering.