UAV-x-NAV

Integrated high precision navigation device for UAVs

Aims

The project UAV-x-NAV aims at developing an integrated high precision navigation device for UAVs. State-of-the-art GNSS and INS components in combination with adequate sensor fusion algorithms will enable the UAV to manoeuver in challenging environments and, furthermore, support photogrammetric applications.

Brief Description

Today, UAVs (Unmanned Aerial Vehicles) are well-established tools for the airborne acquisition of image and video data. UAVs are used in a wide range of applications. These include photogrammetry for creating orthophotos and digital terrain models, the documentation of natural hazards, search campaigns for missing persons or assessments after major emergencies.

UAVs are capable of flying a predefined route and acquiring a desired set of data before returning to the point of departure, all autonomously. The integrated autopilot of an UAV is typically equipped with a GPS receiver which shows a positioning accuracy of 10-20 m. This accuracy will be sufficient for navigating in areas free of obstacles. But there exist numerous applications demanding a much greater positioning accuracy. As an example, when the aircraft is navigated in direct vicinity of an obstacle for the purpose of taking detailed photographs, the position of the UAV has to be pinpointed to less than a meter. For high precision photogrammetric applications, an even higher accuracy at the centimetre-level is needed, especially when no terrestrial reference observations are available.

In the course of the UAV-x-NAV project, the requirements regarding an accurate positioning of UAVs are defined. On this basis, an integrated navigation module is designed. It is emphasized to combine GNSS and IMU data by appropriate filtering techniques to reach a real-time positioning accuracy below the meter-level. Special emphasis is put on the development of a both light and small device, as well as on the communication with other aircraft systems e.g. the autopilot. Existing systems for road vehicle navigation or pedestrian navigation are analyzed and adapted for UAV applications. The current positioning accuracy of the navigation module is the basis for the computation of a safety level which has direct influence on the UAV’s autopilot.