The coming years will see great reliance on Global Navigation Satellite Systems (GNSS) underpinning many aspects of modern technological infrastructure. Europe will shortly launch its own system, Galileo, with applications ranging from precision navigation and surveying to safety of life services, telecoms, and power generation/distribution. However, GNSS signals are vulnerable to ionospheric disturbances that are greatest around solar maximum (next ~2012). Communications (satellite and HF), remote sensing and Earth observation systems are also affected. This symposium is focused on presenting measurement results and interpretation (particularly TEC and scintillations), modelling and simulation of ionospheric processes, error mitigation techniques, ionospheric imaging, addressed to improve ionospheric information for the advanced terrestrial and space-based systems and to help to protect technological systems from the ionospheric threats posed by the forthcoming solar maximum.