The unmanned small airplanes and quadrocopters used for military, intelligence and surveillance purposes are getting widespread in our days. Regarding the flight periods (taking off, flying and landing) of these UAVs (Unmanned Aerial Vehicle) the accurate determination of the flight altitude can be crucial in automated control. However, in the case of UAVs the compact and light design of the sensor devices is of great importance, because it can greatly affect the usability and range of the plane. Although in military applications cost-effectiveness is not the most important aspect, in other applications it must be carefully considered. Such applications can be introduced in the field of data-collection, surveillance, transportation and communication.
The examined system consists of a GPS module, a gyroscope, a barometric altimeter, and a radio altimeter. With this configuration more possibilities are available for altitude measurement. We can measure altitude with the radio altimeter, improving its acquired data with the help of the gyroscope, or we can use the altitude data of either the GPS module or the barometric module.
The thesis concentrates on the possibilities lying in GPS data correction, and the way this corrected data can be used to validate altitude data coming from other sources. Furthermore, it aims at determining the circumstances in which it can be considered as a reliable measurement method.