Selection of the carrier frequency
Measurement of time of arrival data for
position and synchronization calculations
Execution of the Built-in Tests (BIT) for fault
isolation
Generation of alerts
The Network Interface Computer Program
(NICP) is the software that runs in the DDP and is
responsible for the communications with the JTIDS
RF network.
The NICP controls message
transmission and reception processing, coarse and fine
terminal
synchronization,
relative
navigation
processing, and terminal and network monitoring.
Figure 5-9 is the block diagram for the DDPG.
The global memory in the DDP is shared by all the
processors in the terminal. Communications between
the processors is over an internal bus called the plain
text bus. All transactions on the plain text bus are
either read or write commands to the global memory
or port-to-port transfers. When the SICP, running in
the IU, needs to communicate with the NICP, it does
so by using the shared global memory in the DDP. A
port-to-port transfer is a transfer of data between
ports, such as when communicating with the host
external timer (see fig. 5-9).
SECURE DATA UNIT.— The SDU is a
removable assembly that is mounted to the IU. It
stores the cryptovariables that are loaded during
initialization. The SDU provides for both message
security and transmission security. Message security
is provided by the encryption of the data, while
transmission security is provided by the pseudo-
random frequency-hopping pattern and the
introduction of a pseudo-random pattern of noise and
jitter on the RF signal.
RECEIVER/TRANSMITTER GROUP.— The
R/T is in the top drawer of the equipment cabinet and
processes the radio frequency signals. The R/T also
generates a 75-MHz intermediate frequency signal
used for internal communication between the R/T and
DDPG. When a Link-16 message is received, the R/T
5-11
converts the RF to the intermediate frequency and
sends it to the DDPG for processing.
When the
terminal transmits a Link-16 message, the R/T
receives a Continuous Phase-Shift Modulation (CPS)
IF signal from the DDPG. The R/T then converts it to
a 200-watt RF signal that is sent to the high-power
amplifier group.
HIGH-POWER AMPLIFIER GROUP.— The
HPAG is in the second drawer of the equipment
cabinet and consists of a high-power amplifier and the
antenna interface unit (AIU). The signal from the R/T
group is received by the HPAG and amplified from
200 to 1,000 watts. The HPAG can also operate in a
low-power mode, in which case the output signal is
about 200 watts. The AIU provides the interface
between the output of the HPAG and the antenna.
POWER INTERFACE UNIT.— There are two
Power Interface Units (PIUS) in the equipment
cabinet. The fourth drawer is the HPAG PIU and the
bottom drawer is the PIU for the R/T and DDG. The
two PIUS are identical. The three-phase, 115-VAC,
60-Hz input power is converted to two outputs: three
phase, 115-VAC, 400-Hz, and one-phase, 115-VAC
at 400 Hz.
COMMAND AND CONTROL PROCESSOR
The Command and Control Processor (C2P) is a
message distribution system designed to control and
manage the interfaces between the three tactical data
links (Link-4A, Link-11, and Link-16), the operator,
and the hardware.
PURPOSE OF THE C2P
The C2P controls and manages the interfaces
between the various data links on major surface and
aircraft Command and Control (C2) platforms. The
surface platforms that will have the initial installations
of the C2P system are aircraft carriers (CV, CVN) and
AEGIS cruisers (CG), followed by installation on
amphibious assault ships (LHA, LHD), and AEGIS
destroyers (DDG). There are two configurations of
the C2P, one tailored for ships with the Advanced
Combat Direction System (ACDS) Block 0
configuration
and one for ACDS Block 1
