Aircraft radio navigation station
In
radio navigation
, a
VOR/DME
is a
radio beacon
that combines a
VHF omnidirectional range
(VOR) with a
distance-measuring equipment
(DME).
[1]
The VOR allows the receiver to measure its
bearing
to or from the beacon, while the DME provides the
slant distance
between the receiver and the station. Together, the two measurements allow the receiver to compute a
position fix
.
[2]
The VOR system was first introduced in the 1930s, but didn't enter significant commercial use until the early 1950s. It became much more practical with the introduction of low-cost
solid state
receivers in the 1960s. DME was a modification of
World War II
-era navigation systems like
Gee-H
, and began development in 1946. Like VOR, it only became practical with the introduction of solid state receivers during the 1960s.
In 1948, the
United States Congress
directed civilian and military aviation to standardize on VOR/DME equipment. However, the military secretly developed a largely duplicate system called
TACAN
. The system was revealed in 1952, but work continued into 1955, when the redundancy of effort caused controversy.
[3]
[a]
The following year an agreement was reached, where civilian operators would adopt the
VORTAC
system.
[5]
During the mid-1960s,
ICAO
began the process of introducing a standardized radio navigation system for medium-area coverage on the order of a few hundred kilometres. This system would replace the older
Low-frequency radio range
and similar systems used to navigate over national ranges. A number of proposals were submitted, including ones based solely on angle measurements like VOR, solely on distance measures like DME, combinations, or systems that output a location directly, like
Decca Navigator
and
Loran-C
.
VOR/DME eventually won the standardization effort, due to a number of factors. One was that the direct measurement systems like Loran were generally much more expensive to implement (and would be into the 1980s) while Decca had problems with static interference from lightning strikes because of its low 70 to 129
kHz
frequency. The choice of VOR/DME as a hybrid was due largely to it being easier to measure and then plot on a map. With VOR/DME, measurement from a single station reveals an angle and range, which can be easily drawn on a chart. Using a system based on two angles, as an example, requires two measurements at different frequencies (or using two radios) and then the angles plotted from both on a single chart which may be difficult in a cramped cockpit.
Eventually, the FAA began to integrate their VOR/DME facilities with stations based on the TACAN standard, and the stations are called VORTAC.
[6]
Then, most aviation moved to
GNSS
and
GPS
satellite navigation, and only use these older systems as a backup.
References
[
edit
]
- ^
The first DME stations were installed on the airway system in 1952.
[4]
Notes
[
edit
]
- ^
Navigation Programs, Federal Aviation Administration AJM-32 (1986).
VOR, VOR/DME, and Vortac Siting Criteria
. Federal Aviation Administration. p. 2
. Retrieved
28 September
2023
.
{{
cite book
}}
: CS1 maint: numeric names: authors list (
link
)
- ^
Steinmetz, George G.; Bowles, Roland L. (1984).
Development of a VOR/DME Model for an Advanced Concepts Simulator
(PDF)
. Hampton, VA: National Aeronautics and Space Administration
. Retrieved
28 September
2023
.
- ^
Colegrove, Albert M. (4 March 1955).
"Long, Costly Feud Over Navigation System for Planes Near Showdown"
.
Albuquerque Tribune
. Scripps-Howard. p. 24
. Retrieved
26 April
2024
.
- ^
Federal Airway Plan: Fiscal Years 1957 ? 1961
. Civil Aeronautics Administration, U.S. Department of Commerce. December 1955. p. 30
. Retrieved
26 April
2024
.
- ^
Fernsworth, Lawrence (6 September 1956).
"Plane Traffic Dispute Settled"
.
Concord Daily Monitor
. p. 12
. Retrieved
26 April
2024
.
- ^
"Section 1. Navigation Aids"
.
Federal Aviation Administration
. U.S. Department of Transportation. 21 March 2024
. Retrieved
26 April
2024
.