Iridium Satellite Systems

8/8/2019 Iridium Satellite Systems

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by,

B.Amala

H.Phanindra

CVSR college of engineering.


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The Iridium System is asatellite-based, wirelesspersonal communicationsnetwork to permit a wide range

of mobile telephone servicesincluding voice, data andnetworking.

Each satellite is cross-linked tofour other satellites; two

satellites in the same orbitalplane and two in an adjacentplane.


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Each satellite is equippedwith 3 L-band antennasforming a honeycombpattern that consists of 48

individual spot beams witha total of 1628 cells aimeddirectly below the satellite.

Each cell has 174 fullduplex voice channels for atotal of 283,272 channelsworldwide.

3


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o The polar constellation isformed by 6 orbital planeswith 11 satellites per plane.

o The orbital planes are co-axial at the polar axis,separated from each other

at an angle of nearly 30degrees.o Iridium uses 66 operational

satellites configured at aattitude of 780km(spare at648) above the earth in sixnearly polar orbital times of

100 min 28 sec


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5

66

Ope

ration

alSate

llites

12S

pare

Sat

ellite

s


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Iridium basedCommunicatio

n unit

Existingaircraft

communication systems

iridiumgatew

ay

PSTN

phone

Aircraft cockpit communication system

Air to Ground-Voice:


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n unit

Existingaircraft


iridiumgatew

ay


n unit

Existingaircraft


callsetup

Aircraft cockpit communication system Aircraft cockpit communication system

Air to Air-Voice:


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The space segment which includes theLEO satellites and related control facilities.

System control segment

Gateway segmentThe subscriber segment (phones and

pagers) which provide mobile access to thesatellite system and terrestrial wireless

systems.


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Three Principal Elements Of SV:

Payload Provides All Command, Control and Communications FunctionsMain Mission Antennas (MMAs) Provide L-Band Telephony Functions Bus Platform For SV Operations, Provides Power, Pointing, Propulsion

9

Solar Array Panels (2)

Battery &Radiator

Ka-Band Cross-Link Antenna (4)

Ka-Band FeederLink Antenna (4)

L-BandMMA (3)

PayloadElectroncis


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The frequency bands are as follows: L-band subscriber to satellite voice

links=1.616GHZ to 1.6265GHZ

Ka-band gateway downlinks=19.4 GHZ to

19.6GHZ. Ka-band gateway up-links=29.1GHZ to

29.3GHZ

Ka-band inter-satellite cross-links

=23.18GHZ to23.38GHZ


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Using satellite cross links is the unique key to theiridium system and the primary differentiationbetween iridium and the traditional satellite bentpipe system where all transmissions follow a pathfrom earth to satellite to earth.

Iridium is the first mobile satellite to incorporatesophisticated, onboard digital processing on eachsatellite.

Entire global coverage by a single wirelessnetwork systems.

With this system the subscriber will never listen amessage called OUT OF COVERAGE AREA


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Less reliance on wire-line networksContinuous talk timeFewer outagesDont need to be in the in the same footprint as the gatewa

High risk associated with designing, building, and launchingsatellites.

High cost for the terrestrial-based networking and interfaceinfrastructure.

low power, dual mode transceivers are more cumbersome aexpensive


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Commercial point of view: Availability of services and early subscriber take-up will

be the key to survival for operators. Lower infrastructure costs will further help in early break-

even and profitability for network operators.

Economic point of view: Since the satellites has already been launched it is

important that this system is applied as much as

possible. Innovative Applications like seismic alert ofearthquakes and tsunami should be brought.


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Iridium Satellite Systems

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