A DVOR (Doppler VHF Omni Directional Range) is a short/medium-range radio navigation system. It is used to aid aircraft in determining their flight position and direction in relation to their destination. The DVOR is a development from the CVOR (Conventional VHF Omni Directional Range) delivering higher performance. 

DVOR systems at Systems Interface Systems Interface supply and install DVOR on a full turnkey basis. Systems Interface provides engineering expertise to support any stage of the project from site survey and safety case development to commissioning and maintenance support. 

DVORs from Systems Interface are operationally installed in Europe, Africa and Asia.

The ICAO standard short and medium range navigation aid, is the VOR (VHF Omnidirectional Range). They are deployed at airports and strategic en route locations. An aircraft uses a VOR to find its bearing in respect to the beacon's position by receiving a radio signal from the VOR. The two forms of VOR are Conventional VOR (CVOR) and Doppler VOR (DVOR). Both systems operate in the VHF band of 108.000 MHz to 119.975 MHz The DVOR is a development of the CVOR that uses the Doppler effect to provide better signal quality and accuracy than CVOR at adverse locations with challenging geographic conditions.