Which of the following nav aids can provide an RNAV system with position?

The VOR/DME combination stands out as the correct answer because it directly contributes to the position-fixing capabilities of an RNAV (Area Navigation) system. The VOR (VHF Omnidirectional Range) provides directional information, enabling the RNAV system to determine its radial from the station. Meanwhile, the DME (Distance Measuring Equipment) provides distance information from the VOR station.

When these two components are used together, they enable the RNAV system to compute a precise position fix. By knowing both the distance to the VOR and the bearing from it, the aircraft can determine its position in a 2D plane, which is crucial for navigation purposes, especially in terms of maintaining course and altitude.

Other navigation aids may provide valuable information, but they do not offer the same level of position accuracy or integration with RNAV systems. For instance, ADF (Automatic Direction Finder) utilizes NDBs (Non-Directional Beacons) to provide bearing information but lacks the distance component necessary for precise position calculations. Similarly, VDF (VHF Direction Finder) provides bearing information as well, but it is less commonly used compared to VOR/DME systems for RNAV functionality.