3P QUESTIONS AND ANSWERS

3P QUESTIONS AND ANSWERS What is the orbiting altitude of the Iridium satellite communications system? 485 miles. What frequency band is used by the Iridium system for telephone and messaging? MHz. What services are provided by the Iridium system? Digital voice and Data at 2.4 kbps. Which of the following statements about the Iridium system is true? There are 48 spot beams per satellite with a footprint of 30 miles in diameter. What is the main function of the COSPAS-SARSAT satellite system? Monitor 406 MHz for distress calls from EPIRBs. How does the COSPAS-SARSAT satellite system determine the position of a ship in distress? By measuring the Doppler shift of the 406 MHz signal taken at several different points in its orbit. What is the orbital altitude of INMARSAT Satellites? 22,177 miles. Which of the following describes the INMARSAT Satellite system? AOR-E at 15.5° W, AOR-W at 54° W, POR at 178° E and IOR at 64.5° E. What are the directional characteristics of the INMARSAT-C SES antenna? Omnidirectional. When engaging in voice communications via an INMARSAT-B terminal, what techniques are used? CODECs are used to digitize the voice signal. Which of the following statements concerning INMARSAT geostationary satellites is true? They provide coverage to vessels in nearly all of the world's navigable waters. Which of the following conditions can render INMARSAT -B communications impossible? All of these. What is the best description for the INMARSAT-C system? It is a store-and-forward system that provides routine and distress communications. The INMARSAT mini-M system is a: Satellite system utilizing spot beams to provide for small craft communications. What statement best describes the INMARSAT-B services? Voice at 16 kbps, Fax at 14.4 kbps and high-speed Data at 64/54. Which INMARSAT systems offer High Speed Data at 64/54 kbps? M4 and Fleet. When INMARSAT-B and INMARSAT-C terminals are compared: INMARSAT-C antennas are small and omni-directional, while INMARSAT-B antennas are larger and directional. What services are provided by the INMARSAT-M service? Voice at 6.2 kbps, Data at 2.4 kbps, Fax at 2.4 kbps and e-mail. Global Positioning Service (GPS) satellite orbiting altitude is: 12,554 miles. The GPS transmitted frequencies are: 1227.6 MHz and 1575.4 MHz. How many GPS satellites are normally in operation? 24 What best describes the GPS Satellites orbits? They are in six orbital planes equally spaced and inclined about 55 degrees to the equator. How many satellites must be received to provide complete position and time? 4 What is DGPS? A system to provide additional correction factors to improve position accuracy.