Satellite

Key Topic 95:  Low Earth Orbit Systems

3-95P1 What is the orbiting altitude of the Iridium satellite communications system?

A. 22,184 miles.

B. 11,492 miles.

C. 4,686 miles.

D. 485 miles.

Satellite

Key Topic 95: Low Earth Orbit Systems

3-95P2 What frequency band is used by the Iridium system for telephone and messaging?

A. 965 - 985 MHz.

B. 1616 -1626 MHz.

C. 1855 -1895 MHz.

D. 2415 - 2435 MHz.

B. 1616 -1626 MHz.

Satellite

Key Topic 95: Low Earth Orbit Systems

3-95P3 What services are provided by the Iridium system?

A. Analog voice and Data at 4.8 kbps.

B. Digital voice and Data at 9.6 kbps.

C. Digital voice and Data at 2.4 kbps.

D. Analog voice and Data at 9.6 kbps.

C. Digital voice and Data at 2.4 kbps.

Satellite

Key Topic 95: Low Earth Orbit Systems

3-95P4 Which of the following statements about the Iridium system is true?

A. There are 48 spot beams per satellite with a footprint of 30 miles in diameter.

B. There are 48 satellites in orbit in 4 orbital planes.

C. The inclination of the orbital planes is 55 degrees.

D. The orbital period is approximately 85 minutes.

Satellite

Key Topic 95: Low Earth Orbit Systems

3-95P5 What is the main function of the COSPAS-SARSAT satellite system?

A. Monitor 121.5 MHz for voice distress calls.

B. Monitor 406 MHz for distress calls from EPIRBs.

C. Monitor 1635 MHz for coded distress calls.

D. Monitor 2197.5 kHz for hexadecimal coded DSC distress messages.

B. Monitor 406 MHz for distress calls from EPIRBs.

Satellite

Key Topic 95: Low Earth Orbit Systems

3-95P6 How does the COSPAS-SARSAT satellite system determine the position of a ship in distress?

A. By measuring the Doppler shift of the 406 MHz signal taken at several different points in its orbit.

B. The EPIRB always transmits its position which is relayed by the satellite to the Local User Terminal.

C. It takes two different satellites to establish an accurate position.

D. None of the above.

Satellite

Key Topic 96:  INMARSAT Communications Systems-1

3-96P1 What is the orbital altitude of INMARSAT Satellites?

A. 16, 436 miles.

B. 22,177 miles.

C. 10, 450 miles.

D. 26,435 miles.

B. 22,177 miles.

Satellite

Key Topic 96: INMARSAT Communications Systems-1

3-96P2 Which of the following describes the INMARSAT Satellite system?

A. AOR at 35° W, POR-E at 165° W, POR-W at 155° E and IOR at 56.5° E.

B. AOR-E at 25° W, AOR-W at 85° W, POR at 175° W and IOR at 56.5° E.

C. AOR-E at 15.5° W, AOR-W at 54° W, POR at 178° E and IOR at 64.5° E.

D. AOR at 40° W, POR at 178° W, IOR-E at 109° E and IOR-W at 46° E.

Satellite

Key Topic 96: INMARSAT Communications Systems-1

3-96P3 What are the directional characteristics of the INMARSAT-C SES antenna?

A. Highly directional parabolic antenna requiring stabilization.

B. Wide beam width in a cardioid pattern off the front of the antenna.

C. Very narrow beam width straight-up from the top of the antenna.

D. Omnidirectional.

Satellite

Key Topic 96: INMARSAT Communications Systems-1

3-96P4 When engaging in voice communications via an INMARSAT-B terminal, what techniques are used?

A. CODECs are used to digitize the voice signal.

B. Noise-blanking must be selected by the operator.

C. The voice signal must be compressed to fit into the allowed bandwidth.

D. The voice signal will be expanded at the receiving terminal.

A. CODECs are used to digitize the voice signal.

Satellite

Key Topic 96: INMARSAT Communications Systems-1

3-96P5 Which of the following statements concerning INMARSAT geostationary satellites is true?

A. They are in a polar orbit, in order to provide true global coverage.

B. They are in an equatorial orbit, in order to provide true global coverage.

C. They provide coverage to vessels in nearly all of the world’s navigable waters.

D. Vessels sailing in equatorial waters are able to use only one satellite, whereas other vessels are able to choose between at least two satellites.

Satellite

Key Topic 96: INMARSAT Communications Systems-1

3-96P6 Which of the following conditions can render INMARSAT -B communications impossible?

A. An obstruction, such as a mast, causing disruption of the signal between the satellite and the SES antenna when the vessel is steering a certain course.

B. A satellite whose signal is on a low elevation, below the horizon.

C. Travel beyond the effective radius of the satellite.

D. All of these.

Satellite

Key Topic 97:  INMARSAT Communications Systems-2

3-97P1 What is the best description for the INMARSAT-C system?

A. It provides slow speed telex and voice service.

B. It is a store-and-forward system that provides routine and distress communications.

C. It is a real-time telex system.

D. It provides world-wide coverage.

Satellite

Key Topic 97: INMARSAT Communications Systems-2

3-97P2 The INMARSAT mini-M system is a:

A. Marine SONAR system.

B. Marine global satellite system.

C. Marine depth finder.

D. Satellite system utilizing spot beams to provide for small craft communications.

Satellite

Key Topic 97: INMARSAT Communications Systems-2

3-97P3 What statement best describes the INMARSAT-B services?

A. Voice at 16 kbps, Fax at 14.4 kbps and high-speed Data at 64/54.

B. Store and forward high speed data at 36/48 kbps.

C. Voice at 3 kHz, Fax at 9.6 kbps and Data at 4.8 kbps.

D. Service is available only in areas served by highly directional spot beam antennas.

A. Voice at 16 kbps, Fax at 14.4 kbps and high-speed Data at 64/54.

Satellite

Key Topic 97: INMARSAT Communications Systems-2

3-97P4 Which INMARSAT systems offer High Speed Data at 64/54 kbps?

A. C.

B. B andC.

C. Mini-M.

D. B, M4 and Fleet.

Satellite

Key Topic 97: INMARSAT Communications Systems-2

3-97P5 When INMARSAT-B and INMARSAT-C terminals are compared:

A. INMARSAT-C antennas are small and omni-directional, while INMARSAT-B antennas are larger and directional.

B. INMARSAT-B antennas are bulkier but omni-directional, while INMARSAT-C antennas are smaller and parabolic, for aiming at the satellite.

C. INMARSAT-B antennas are parabolic and smaller for higher gain, while INMARSAT-C antennas are larger but omni-directional.

D. INMARSAT-C antennas are smaller but omni-directional, while INMARSAT-B antennas are parabolic for lower gain.

Satellite

Key Topic 97: INMARSAT Communications Systems-2

3-97P6 What services are provided by the INMARSAT-M service?

A. Data and Fax at 4.8 kbps plus e-mail.

B. Voice at 3 kHz, Fax at 9.6 kbps and Data at 4.8 kbps.

C. Voice at 6.2 kbps, Data at 2.4 kbps, Fax at 2.4 kbps and e-mail.

D. Data at 4.8 kbps and Fax at 9.6 kbps plus e-mail.

C. Voice at 6.2 kbps, Data at 2.4 kbps, Fax at 2.4 kbps and e-mail.

Satellite

Key Topic 98:  GPS

3-98P1 Global Positioning Service (GPS) satellite orbiting altitude is:

A. 4,686 miles.

B. 24,184 miles.

C. 12,554 miles.

D. 247 miles.

C. 12,554 miles.

Satellite

Key Topic 98: GPS

3-98P2 The GPS transmitted frequencies are:

A. 1626.5 MHz and 1644.5 MHz.

B. 1227.6 MHz and 1575.4 MHz.

C. 2245.4 and 2635.4 MHz.

D. 946.2 MHz and 1226.6 MHz.

B. 1227.6 MHz and 1575.4 MHz.

Satellite

Key Topic 98: GPS

3-98P3 How many GPS satellites are normally in operation?

A. 8

B. 18

C. 24

D. 36

C. 24

Satellite

Key Topic 98: GPS

3-98P4 What best describes the GPS Satellites orbits?

A. They are in six orbital planes equally spaced and inclined about 55 degrees to the equator.

B. They are in four orbital planes spaced 90 degrees in a polar orbit.

C. They are in a geosynchronous orbit equally spaced around the equator.

D. They are in eight orbital planes at an altitude of approximately 1,000 miles.

Satellite

Key Topic 98: GPS

3-98P5 How many satellites must be received to provide complete position and time?

A. 1

B. 2

C. 3

D. 4

Satellite

Key Topic 98: GPS

3-98P6 What is DGPS?

A. Digital Ground Position System.

B. A system to provide additional correction factors to improve position accuracy.

C. Correction signals transmitted by satellite.

D. A system for providing altitude corrections for aircraft.