Tactical Air Navigation
TACtical Air Navigation, or TACAN, is a navigation system used by military aircraft. It provides the user with a distance and bearing from a ground station. It is a more accurate version of the VHF omnidirectional range / Distance Measuring Equipment (VOR-DME) system that provides range and bearing information for civil aviation. At VORTAC facilities, the DME portion of the TACAN system is available for civil use.
Operation
TACAN in general can be described as the military version of the VOR-DME system. It operates in the frequency band 960-1215 MHz. The bearing unit of TACAN is more accurate than a standard VOR since it makes use of a two frequency principle, with 15 Hz and 135 Hz components.
The distance measurement component of TACAN operates with the same specifications as do civil DME's. Therefore to reduce the number of required stations, TACAN stations are frequently co-located with VOR facilities. These co-located stations are known as VORTAC's. This is a station composed of a VOR for civil bearing information and a TACAN for military bearing information and military/civil distance measuring information. The TACAN transponder performs the function of a DME without the need for a separate, collocated DME. Because the rotation of the antenna creates a large portion of the azimuth signal, if the antenna fails, the azimuth component is no longer available and the TACAN downgrades to a DME only mode.
TACAN can operate in either receive mode (R), or transmit/receive (TR) mode.
FlightGear
A few planes in FlightGear are equipped with TACAN. Here's a list of known aircraft with TACAN:
- A-6E
- A-10
- A4F
- B-1B
- Blackburn Buccaneer
- Dassault Mirage 2000-5
- Fiat G91R1B
- General Dynamics F-16 Fighting Falcon
- Grumman F-14 Tomcat
- Lightning
- McDonnell Douglas F-15 Eagle
- T38
To set TACAN, go to the Equipment > Radio Settings dialog. When using in-air refuel, first read Howto: Air-Air Refueling.
The F-14 and F-15 have a TACAN control panel that needs to be set correctly. Refer to their documentation pages for more information.
Example property values
/instrumentation/tacan/
display/
channel=029Y
frequency/
selected-mhz=109.25
ident=NMZ
in-range=true
indicated-bearing-true-deg=...
indicated-distance-nm=...
name=USS Nimitz TACAN
servicable=true
switch-position=1
/instrumentation/tacan/display/channel and /instrumentation/tacan/frequency/selected-mhz are linked.