Gravity surveys are used to compute regional or national geoid models. The use of an aircraft or helicopter for photogrammetry is fast but very expensive. Doing it on the ground takes a long time, and therefore also expensive, and one cannot always access each location. Drones have opened up to monitor areas with unprecedented accuracy and fast survey times. In 2021 TeroMovigo won a project proposal to be part of the ESA Business Incubation to install an accurate Inertial Measuring Unit (IMU) inside a drone to observe the variations in the Earth’s gravity field with mGal precision (i.e., 1 millionth of the average gravity force) on a regional to national scale. The combination of satellite and drone gravity data can produce a geoid with 2-5 cm accuracy.
