Tsunami can be an immensely destructive geohazard as seen from the 2004 Indian Ocean tsunami that killed nearly a quarter of a million people in a single incident. Unlike earthquakes or volcanoes, tsunamis can be forecast; here, warning time is the most critical factor to save people and resources. To increase the lead time for warning, this study suggests a disruptive idea of identifying geohazards better and faster than the current ground-based systems. Our idea is to detect the atmospheric waves propagating faster than tsunami waves from a constellation ('network') of CubeSats equipped with GPS receivers. We present the observations of the travelling ionospheric disturbance (TID) all around the world after the Hunga-Tonga Hunga-Ha'apai volcanic eruption on 15th of January, 2022. We discuss the results of the speed and spatial extent of the atmospheric disturbance from processing of a number of CubeSat GPS data and how much time the orbital TID detection can increase warning time for tsunami in comparison to the ground based measurements. Finally, we propose a new mission of utilising the atmosphere as a global sensing system for rapid detection of geohazard and extreme weather events, advanced early warning, and disaster risk reduction, by exploiting dense intersatellite links between GNSS/GPS and nanosatellite constellations.