How are satellites and spacecraft communicated with and controlled.. Is it all based on an IP network? Like lets say the cassini spacecraft. They just point their radio dishes at it and start sending IP packets? I really have no clue how satellite communications work!
2007-03-07 18:45:50 · 4 answers · asked by Fancy Mc Pants 1 in Science & Mathematics ➔ Engineering
Communications satellites are not an extension of the earth's global IP network. The majority of communications satellites today send and receive frequency modulated (FM) digital signals.
FM is chosen over other modulation schemes for its unique ability to tolerate amplitude distortions and phase dispersions. FM better tolerates spectral intermodulations so the satellite-based power amplifiers can be biased lower to use less solar power for the same radio wave transmit power. FM also allows receivers to achieve signal-to-noise ratios better than carrier-to-noise ratios.
In digital FM, the streams of digital bits are divided into small groups of few bits. Each group of bits of a given bit pattern, called a symbol, is mapped to a unique radio frequency within the transmit band of contiguous carrier frequencies. The carrier frequencies are in the GHz range.
The sending earth stations use highly focused antennae to beam those FM radio waves to the geosynchronous communications satellites. The satellites act like bent-pipes to bend the radio wave beams back to the receiving earth stations.
The earth stations also beam FM streams of control commands, users authentication data, and software-download sequences to the satellites.
In addition to communications satellites there are many other types of satellites: military uses, GPS, weather forecasts, radio and TV broadcast, mobile phones, etc...
2007-03-07 20:57:17 · answer #1 · answered by sciquest 4 · 0⤊ 0⤋
There are control programs written specifically for the on board computers that operate the craft controls. These programs can be quite complex, or very simple. It really all depends on what ground control needs the craft to do. For communications satellites, it's position and altitude is about all that is needed. The ability to turn on, direct the thrust to push it back to where it belong is about all that is needed. It isn't a lot more than what you might find on a remote control airplane, just a bit more precise positional data. There is neither room for, or need of a lot of complicated system control for those craft. Lockheed Martin, NASA or JPL might be able to give you some information on this as well.
2007-03-07 18:56:17 · answer #2 · answered by Anonymous · 0⤊ 0⤋
there is satellite tv for pc to satellite tv for pc communications potential on some satellites that pick it. whether, you at the instant are not likely to get entry to that communications and it wasn't placed there to mitigate a satellite tv for pc no longer being over your head.
2016-11-23 14:50:20 · answer #3 · answered by block 4 · 0⤊ 0⤋
no ,
its a little more complcated then that.
remember the transmission speeds are not as fast as going
across a wire. they have to transmit across free space.
you have to treat everything as if it were an a analog signal that
has to be digitized. Then, it has to match the communications protocol that is at the recieving equipment. etc..
2007-03-07 19:06:26 · answer #4 · answered by 987654321abc 5 · 0⤊ 0⤋