(Illustration Not Available)
AN/ARN-118 TACAN Navigation Set
and distance for updating the inertial system information.
1. Brief Description: The AN/ARN-118 is a major
The TACAN RT outputs are processed by the signal data
component of the ANIASN-132 Integrated Inertial
converter for compatibility with the multiplex data buses.
Navigation System (IINS). The position error of an
The TACAN RT also produces and transmits distance
inertial navigation system increases with time; therefore,
information when interrogated in the air-to-air operation
a position reference sensor is used to update the inertial
by another TACAN equipped aircraft; however, this air-
data, and thereby bound the time-growing position error.
to-air mode precludes using the TACAN information to
The IINS derives position updates from the TACAN
update the IINS. Major components of the AN/ARN-118
range and bearing measurements.
determines the relative bearing of the aircraft from a
selected TACAN around station and determines the
MT-491 5/A ........................ Mount
distance or range of the station. The TACAN operates
RT-1159/A .......................... Receiver-Transmitter
within 390 nautical miles of a TACAN ground station.
Since the TACAN system operating limit is line of sight,
2. Applicable Tools and Test Equipment:
the actual operating range is dependent on aircraft
altitude. The TACAN system operates on a selected
channel from 252 available channels. The 252 channels
are equally divided into 126 x-channels and 126 y-
3. Applicable Publications:
channels with both x and y channels spaced at 1 MHz
intervals. Upon being interrogated by the ANIARN-118,
the ground station beacon transmits a signal. From this
signal, the AN/ARN-118 computes the values of bearing