28-12-2012, 06:52 PM
Types of Satellite Orbits
[attachment=45699]
LEO
Typically at an altitude of 760-1,800 km
The strength of the signal goes up by 13 times.
Orbit height is lower than GEO, so coverage is complete including polar regions.
Propagation delay comes down to 10 ms in case of LEO from 250 ms (in case of GEO).
The footprint of a satellite is divided into spot beams , which facilitate the reuse of frequencies.
Geosynchronous satellite serve upto 150 spot beams, while LEO serve typlically 20(max.) spot beams.
The LEO’s demand a larger number of satellites to keep up the links.
These satellites provide overlapping coverage to provide to ensure a continuous coverage.
Types of LEO’s:
Little LEOs :
a) Provide low speed text and data services. Comparable to paging systems.
b) Small size of satellite and low cost of implementation.
c) Used in limited internet access, environmental monitoring, two way paging, remote monitoring etc.
Big LEOs : a) Equivalent to cellular telephone services
b) Offers global voice, facsimile and possibly broadband services.
c) Computer(internet) networking offered by optical fibres.
Broadband LEOs :
Similar to fibre-optic networks. Application based on three categories-
Narrowband(upto 64 Kbits/sec)
Wideband (from 64 Kbits/sec to 1.544/2.048 Mbit/sec) .
Broadband (above 1.544/2.048 Mbit/sec).
[attachment=45699]
LEO
Typically at an altitude of 760-1,800 km
The strength of the signal goes up by 13 times.
Orbit height is lower than GEO, so coverage is complete including polar regions.
Propagation delay comes down to 10 ms in case of LEO from 250 ms (in case of GEO).
The footprint of a satellite is divided into spot beams , which facilitate the reuse of frequencies.
Geosynchronous satellite serve upto 150 spot beams, while LEO serve typlically 20(max.) spot beams.
The LEO’s demand a larger number of satellites to keep up the links.
These satellites provide overlapping coverage to provide to ensure a continuous coverage.
Types of LEO’s:
Little LEOs :
a) Provide low speed text and data services. Comparable to paging systems.
b) Small size of satellite and low cost of implementation.
c) Used in limited internet access, environmental monitoring, two way paging, remote monitoring etc.
Big LEOs : a) Equivalent to cellular telephone services
b) Offers global voice, facsimile and possibly broadband services.
c) Computer(internet) networking offered by optical fibres.
Broadband LEOs :
Similar to fibre-optic networks. Application based on three categories-
Narrowband(upto 64 Kbits/sec)
Wideband (from 64 Kbits/sec to 1.544/2.048 Mbit/sec) .
Broadband (above 1.544/2.048 Mbit/sec).