VHF omni range equipment (VOR), a short-range radio navigation aid that gives aircraft their bearing to a ground station on VHF frequencies.

Aviation navigation aids need authority certification (ICAO annex 10) and frequency licences; state frequency, power and monitoring system, and provide documentation. Radio, broadcast and surveillance equipment needs destination radio licensing and type approval (WPC, CE-RED, FCC), correct frequency bands, anti-static and shock-resistant packaging, export control and end-use checks for transmitters, radar and tracking devices, and serial or IMEI lists on the invoice.