Maximum Useable Frequency— This option
calculates the best frequency for use based on
geographic location, time of day, current
sunspot activity and other factors that can
affect HF radio-wave propagation.
M u l t i - F r e q u e n c y
Link— T h e
multi-frequency link enables the operation of
Link-11 on up to four frequencies. Normally,
multi-frequency
link
uses
three
HF
frequencies and one UHF frequency.
REMOTE CONTROL UNIT— The remote
control unit is a personal computer based unit that
allows the operator to control the data terminal from
a remote location.
THE JOINT TACTICAL INFORMATION
DISTRIBUTION SYSTEM (LINK-16)— Link-l6
is a new data link that provides for the real-time
exchange of tactical data between Naval, Joint
Service, and NATO units. It includes many of the
functions of the current Link-11 and Link-4A
systems. Link-16 expands many of these functions
and includes several new features that the other
systems lack.
These new features include the
following:
Nodelessness— Nodelessness means that no
one unit is required to maintain link
operations. Once the net is established, it can
continue to operate regardless of the
participation of any particular unit.
Jam resistance— Link-16 data is not
transmitted on any particular frequency, but
changes frequency every 13 microseconds.
For additional security, a pseudo-random
pattern of noise and jitter is added to the
signal. The combination of frequency hopping
and the noise and jitter makes the transmitted
signal hard to detect and jam.
Flexibility
of
communication
operations— Link-16 provides both data and
voice communications circuits. In addition,
different data packing methods allow for
5-14
variation in the amount of data transmitted
during a given time slot.
Separate transmission and data security
features— Link-16
transmissions are
protected by encrypting the data, frequency
hopping, and adding a pseudo-random noise
pattern to the signal before transmitting
Network navigation features— The relative
navigation module is a software routine run by
the Link-16 terminal that compares the time of
receipt of a transmission against the time it
was sent and calculates the distance of the
sending unit from the receiving unit. This
information is correlated against reported
geographic position and used to maintain net
synchronization
and improve positional
accuracy.
Secure voice capabilities— The Link-16
system secure voice communications have the
same transmission safeguards as data
transmissions.
Link-16 also provides the following new or
enhanced capabilities:
Number of Participants— The number of
participants that can participate in a Link-16
net has been increased dramatically. Using a
five-digit octal number for addressing, a
possible 32,766 addresses are available.
Track Numbers— Link-16 replaces the old
four-digit (octal) track numbers used with
Link-11 with a five-character alphanumeric
track number.
This increases the track
number capacity from 4,092 to 524,284.
Track Quality— Link-16 track quality is
improved by comparing the reported position
of a track with the actual position of the track.
To achieve the maximum track quality, a track
must be within 50 feet of its reported position.
Track Identification— The information
reported when identifying a track has been
