What are fixes and navaids?
Every dot on a controller's radar scope represents a named point in the sky. Some are physical radio stations on the ground. Others are just coordinates in a database. Together, they form the skeleton of the airspace - the points that routes, procedures, and clearances are built around.
Navaids: radio stations on the ground
Before GPS, aircraft navigated by tuning into ground-based radio stations called navigation aids (navaids). Three types still matter today:
VOR (VHF Omnidirectional Range) is the backbone of the old system. A VOR station broadcasts a signal that lets an aircraft determine its bearing from the station. Tune to the Kennedy VOR on 115.9 MHz and you know you're on the 045 radial (northeast of the station). Most jet routes and victor airways are defined by VOR-to-VOR segments.
NDB (Non-Directional Beacon) is older and less accurate. It broadcasts a simple signal that the aircraft's ADF (Automatic Direction Finder) points toward. NDBs are being decommissioned across the US and Europe, but you'll still find them at smaller airports and in many countries worldwide.
DME (Distance Measuring Equipment) tells the aircraft how far it is from the station. Often co-located with a VOR, giving pilots both bearing and distance. A position like "JFK VOR, 15 DME on the 220 radial" pinpoints exactly where you are.
How they look on the radar
This is what a controller sees on the radar scope. Each type has a distinct symbol:
- VOR (blue triangle) - the main radio navaid, with frequency shown
- NDB (magenta circle) - older radio beacon, with frequency in kHz
- DME (cyan diamond) - distance measuring equipment
- Fix (green diamond) - GPS waypoint, no radio equipment
Entry and exit points use the same diamond shape but in green (entry) or orange (exit).
Fixes: points in space
A fix is just a named geographic coordinate. No radio station, no physical equipment. It exists as a latitude/longitude in navigation databases.
Fixes have five-letter names like MERIT, GREKI, PARCH, or BOSTN. Some are placed at airway intersections. Others mark key points on SIDs, STARs, and approach procedures. A few are just there for traffic flow management.
The names are usually pronounceable nonsense words, but controllers in each region have their favorites. New York has MERIT and GREKI. Chicago has PLANO and DUFEE. Sometimes the names are inside jokes or references to local landmarks.
GPS changed everything
Modern aircraft don't really need ground-based navaids anymore. GPS gives continuous, accurate position data anywhere on earth. An aircraft can fly direct to any fix, VOR, or arbitrary coordinate without tuning a single radio frequency.
This is why RNAV (Area Navigation) routes are replacing traditional airways. Instead of zigzagging between VOR stations, aircraft can fly optimized paths through GPS waypoints placed wherever makes sense for traffic flow.
VORs still serve as backups when GPS fails and as the foundation for older procedures. But the trend is clear - the FAA has been decommissioning VORs and will keep doing so.
Why controllers care
Controllers don't think much about how the aircraft navigates. What matters is that the pilot can get to the assigned fix reliably. "Direct MERIT" works whether the pilot uses VOR radials, GPS, or a combination.
Fixes and navaids serve as reference points for everything:
- Clearances: "proceed direct GREKI"
- Crossing restrictions: "cross PARCH at FL240"
- Holding patterns: "hold at BOSTN"
- Handoff points: where traffic transfers between sectors
- Reporting points: where pilots call in their position
In radarcontrol.io
Waypoints are displayed on the radar scope for every airspace with the symbols shown above. All 188 airspaces include real navaid data sourced from FAA NASR and OurAirports databases. US airspaces use FAA data with VOR frequencies and airway associations. International airspaces use worldwide navaid positions from OurAirports.
Use direct MERIT or d MERIT to route aircraft to any fix. The command reference covers all routing commands.
Related: What are airways? | What is a SID and STAR? | What is an ARTCC?
Guides: Command reference | Airspace list
Play New York Center - see real VORs, NDBs, and fixes on the radar scope.