4.14 INMARSAT Flashcards
What does INMARSAT stand for?
International maritime satellite
What does BLOS stand for?
Beyond-line-of-sight
What does BGAN stand for?
Broadband global area network
Describe INMARSAT capability
BLOS
Worldwide data and voice communication
Over commercial satellite
What is the max IP data connectivity for INMARSAT?
128 KB/SEC
What voice comms are available via INMARSAT?
Flight deck voice comms
In general, describe the INMARSAT signal flow once it leaves the aircraft
Four satellites, spot beam
Global beams cover a hemisphere
L-band 40 ground stations
Communication services are delivered through the spot beams from four INMARSAT satellites and global beams covering a complete hemisphere.
Approximately 40 ground stations handle user traffic on the L-band frequencies (1530 to 1660.5 MHz).
What does NCTAMS stand for?
naval computer and telecommunications area master station
What does ADNS stand for?
Automated digital network system
What is the nomenclature for the INMARSAT terminal?
HSD-440
What is the function of the HSD-440?
Comm link between the aircraft and the INMARSAT network
The HSD-440 (Figure 4-219) is a satellite communications terminal that provides a communication link with the INMARSAT satellite communication network and interfaces with the MCDS and FMCS.
Where is the HSD-440 located?
Upper fuselage
Beneath the vert stab
The INMARSAT terminal is located in the upper fuselage beneath the vertical stabilizer accessible via an
access hatch adjacent to the aft door (Figure 4-218).
What does ACU stand for?
Antenna control unit
What is another name for the ACU?
BSU
Beam steering Unit
What does D/LNA stand for?
Duplexes/low noise amplifier
Where is the INMARSAT antenna system located?
Top of the vertical stabilizer
Warning regarding INMARSAT transmissions
Failure to maintain proper standoffs may result in exposure to RF radiation.
What is the function of the INMARSAT ACU?
Points the antenna based on info from the HSD-440
The ACU translates the antenna pointing signal received from the HSD-440 into motor drive signals to steer the antenna. The ACU provides filtered 28 Vdc power to the D/LNA and antenna. The ACU sends D/LNA and antenna BIT status to the MCDS via the HSD-440. The ACU is located aft of the antenna (Figure 4-220).
What is the function of the D/LNA for the INMARSAT system?
Amplifies RF signals
The D/LNA assembly is a combined diplexer and low-noise amplifier. The diplexer combines the transmit and receive paths into a single path to the antenna. The LNA amplifies all received RF signals. The D/LNA is powered by the ACU. The D/LNA is mounted on the vertical stabilizer under the antenna (Figure 4-220).
What is the function of the TACLANE?
Encrypts INMARSAT system
Note regarding removing power from the TACLANE
TACLANE CIK is removed after power is secured to the
TACLANE components.
Note regarding TACLANE keys when a tamper condition is detected
All keys are automatically deleted when a tamper condition is
detected.
Briefly describe the INMARSAT signal flow internal to the aircraft
NA
Where do you power on INMARSAT?
SPDS
How long does INMARSAT take to power up initially? After cycling power?
INMARSAT components complete
initialization within 3.5 minutes of applying power and 2.3 minutes, if cycling power
Where do you access INMARSAT via TOMS?
Comms PEP tab
OCM
