SATELLITE MULTIPLE ACCESSING ARRANGEMENTS (c26)

CHAPTER 26
SATELLITE MULTIPLE ACCESSING ARRANGEMENTS

1)
Also called as Multiple Destination, It implies that more than one user has access to one or more radio channels within a satellite communications channel.
 Multiple Accessing

Multiple Accessing Arrangement:
 Frequency-division multiple accessing (FDMA)
 Time-division multiple accessing (TDMA)
 Code-division multiple accessing (CDMA)

2)A given number of the available voice-band channels from each earth station are assigned a dedicated destination.
Pre-assignment(dedicated)
 

3)Voice channels are assigned on an as-needed basis.
Demand Assignment
 

4)The method of assigning adjacent channels different electromagnetic polarizations and is possible by using orthogonal polarization and spacing adjacent channels 20 MHz apart.
Frequency Reuse
 

5)Eskimo word meaning “little brother”.
Anik
 

6)Domestic Satellites operated by Telsat Canada.
Anik-E communications Satellite
 

7)A method of multiple accessing where a given RF bandwidth is divided into smaller frequency bands.
FDMA
 

8)Multiple channel per carrier formats assigned and remain fixed for a long Period of time.
Fixed-Assignment, Multiple Access (FAMA)

9)Assigning carrier frequency on temporary basis using a statistical assignment process.
Demand-Assignment
Multiple Access
 

10)An acronym for Single-channel-per-carrier PCM multiple Access Demand-assignment Equipment.
SPADE
 

11)Stands for Single-Carrier-Per-Channel.
SCPC
 

12)A time division-multiplexed transmission that is frequency division multiplexed.
Common Signaling Channel (CSC)
 

13)The predominant Multiple-access method of time-division multiplexing digitally modulated carriers between participating earth stations within a satellite network through a common satellite transponder.
TDMA
 

14)An RF-to-RF repeater that simply receives the earth station transmissions, amplifies them, and then re-transmit them in a downlink beam that is received by all other participating station.
Transponder
 

15)It is where transmissions from all earth stations are synchronized.
Reference Burst
 

16)It is where all receiving stations recover a frequency and phase coherent carrier for PSK demodulation
Carrier Recovery Sequence (CRS)
 

17)An acronym for Conference of European Postal and Telecommunications Administrations, is commonly used TDMA frame format for digital satellite system
CEPT
 

18)Sometimes referred to as Spread-Spectrum Multipleentire allocated bandwidth Access, the transmissions can spread throughout the
Code-Division Multiple Access (CDMA)

19)A unique binary word that each earth station’s transmissions are encoded.
Chip Code
 

20)It compare two signals and recover the original data.
Correlator
 

21)It assigns an individual terrestrial channel (TC) to a particular satellite channel (SC) for the duration of the call.
Digital non interpolated Interface
 

22)It assigns a terrestrial channel to a satellite channel only when speech energy is present on the TC.
Digital Speech Interpolated Interface
 

23)A form of analog channel compression that has been used for sub oceanic cables for many years.
Time-Assignment Speech Interpolation (TASI)
 

24)The art or science of plotting, ascertaining or directing the course of movements, in other words, knowing where you are and being able to find your way around.
Navigation
 

25)It is the most ancient and rudimentary method of navigation and simply continuing to travel about until you reach your destination, assuming of course that you have one.
Wandering
 

26)Earliest effective means of navigation wherein direction and distance are determined from precisely timed sightings of celestial bodies, including the stars and moon.
Celestial Navigation
 

27)Method of navigation by means of fixing a position and direction with respect to familiar, significant landmarks such as railroad tracks, water towers, barns, mountains and bodies of water.

Piloting

28)A navigation technique that determines position by extrapolating a series of measured velocity increments.
Dead Reckoning
 

29)The term derived from the word “deduced” and not necessarily from the fate of the people who used the technique.
Dead
 

30)He used dead reckoning successfully in 1927 during his historic 33-hour transatlantic journey.
Charles Lindbergh
 

31)She attempted to make the first around-the-world in 1937 using the dead reckoning technique.
Amelia Earhart
 

32)Navigation technique wherein the position is deter-mined by measuring the travel time of an electro magnetic wave as it moves from a transmitter to a receiver.
Radio Navigation
 

33)A radio Navigation system for terrestrial surface broadcast.
Decca
 

34)Radio Navigation system that provide global coverage and terrestrial surface broadcast.
Omega
 

35)Also a terrestrial surface broadcast.
LORAN
 

36)Low-orbit satellite broadcast, provides global coverage.
Navy Transit GPS
 

37)Medium-orbit satellite broadcast also provides global coverage.
Navstar GPS
 

38)Means of radio navigation in which receivers acquire Coded signals from two pairs of high-powered, land based transmitters whose locations are precisely known.
LORAN
 

39)An acronym for Navigation System with Time and Ranging.
Navstar

40)An abbreviation for Global Positioning System.
GPS

Two levels of service or accuracy:
 Standard Positioning Service
 Precise Positioning Service

41)A satellite-based open navigation system which simply means that it is available to anyone equipped with a GPS receiver.
 Navstar GPS

Consists of three segments:
 a space segment
 a ground control segment
 user segment

42)It is when was the Navstar declared as fully operational by the U.S. Air Force Space Command.
April 27, 1995
 

43)It was completed in 1994 and is maintained by the United States Air Force.
Navstar Satellite System
 

44)A positioning and timing service that is available to all GPS users on a continuous, worldwide basis with no direct change.
Standard Positioning Service
 

45)Sometimes called Space Segment, consists of 24operational satellites revolving around Earth in six orbital planes approximately 60° apart with four satellites in each plane.
Satellite Segment
 

46)It produces highly accurate timing signals for satellites.
Cesium Atomic Clock
 

47)A unique integer number that is used to encrypt the signal from that satellite.
Pseudorandom Noise (PRN) Code Number
 

48) A term associated with a table showing the position of a heavenly body on a number dates in a regular sequence, in essence, an astronomical almanac.
Ephemeris

49)Error in the receiver’s clock which affects the accuracy of the time-difference measurement.
Clock Bias Error
 

50)The Navstar control segment.
It consists of :
 Fixed-location ground based monitor stations
 Master Control Station
 uplink transmitter
Operational Control System
 

51)It makes standard GPS more accurate. It works by canceling out most of the natural and man-made errors that creep into normal GPS measurements.
Differential GPS