A Low-Cost Low-Power Chirp Ionosonde for Studying the Ionospheric Impacts of Space Weather

The ionosphere is a region of the atmosphere characterized by both ions and electrons. It is highly active and experiences changes in parameters such as electron density at different altitudes, based on the energy absorbed from the sun. Ionosondes are a type of radar used to gather data about the height of the ionosphere by transmitting a signal towards the ionosphere. This signal is refracted back to the Earth’s surface and received in such a manner that return echoes can be timed to calculate the height profile of the bottomside ionosphere. Traditional ionosondes require large antenna systems and high amounts of power. Recent advancements in software defined radio (SDR) technology, advanced digital signal processing, and computational efficiency enable the size, cost, and power demands of an ionosonde system to be reduced. An Ettus N200 Universal Radio Peripheral was used in our system to verify the reliability of our methods, and during the 2024 total solar eclipse, the system was successfully used to sound the ionosphere. It recorded virtual layer height data comparable to multimillion-dollar ionosonde systems. Since then, we have updated the system to use the newer Red Pitaya SDRlab 122-16. This more affordable board is able to sound the ionosphere, using the same methods as the Ettus based system. Additionally, the system is now in a smaller and more portable form. Currently, we are improving its ability to collect data automatically and be controlled remotely. Furthermore, we are continuing to improve our sounding methods to obtain more data using the same hardware.