Using distributive networks of single frequency HF transmitters and receivers to measure spatial and temporal ionospheric perturbations

The Air Force Research Laboratory (AFRL) and Space Dynamics Laboratory (SDL) operate a network of passive HF radio receivers. These receivers can process a wide variety of HF transmissions from devices such as Digisondes and CODAR coastal radars. By measuring Doppler and path length from multiple transmit stations we can resolve ionospheric conditions and perturbations spatially and temporally. Perturbations include travelling ionospheric disturbances (TIDs) from the 2023 solar eclipse, a Falcon 9 spacecraft reentry, and infrasound waves from 1-ton and 10-ton explosives. We measured the solar eclipse and Falcon 9 reentry using CODAR transmissions and the explosives using a network of Digisondes operating in a single frequency mode.

Approved for public release; distribution is unlimited. Public Affairs release approval #AFRL-2025-1670