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JackS Occasional Visitor
Joined: Apr 09, 2004 Posts: 13 Location: Sinking Spring, OH, USA
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Posted: Mon Jan 16, 2006 5:53 pm Post subject: SPS and PPS? |
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I'm having trouble finding up to date info on this subject. Is there still such a thing as SPS (Standard Positioning Service) and PPS (Precise Positioning Service)? What relationship do SPS and PPS have with SA?
Thank you! |
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nej Frequent Visitor
Joined: Jun 16, 2004 Posts: 454 Location: London, Ingerlund
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Posted: Tue Jan 17, 2006 6:24 pm Post subject: |
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Selective Availability was switched off by presidential order back in 2000 (I think).
There are still two signals being broadcast - C/A (Course/Aquisition) which is the "civilian" signal that we all use and the P (precise) signal that is encrypted and used only by the military. Naturally, the military one is far more accurate (that's how they fly missiles through the windows of houses. Now they just need to work on getting the right houses ) |
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nej Frequent Visitor
Joined: Jun 16, 2004 Posts: 454 Location: London, Ingerlund
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Posted: Tue Jan 17, 2006 6:25 pm Post subject: |
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And to expand, Selective Availability was a built-in error inducing system, which bodged the C/A signal to make it not so accurate (about 50 meters). Without it we can now get 5-10 meters. |
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JackS Occasional Visitor
Joined: Apr 09, 2004 Posts: 13 Location: Sinking Spring, OH, USA
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Posted: Tue Jan 17, 2006 9:56 pm Post subject: |
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Thank you, nej.
I think you mean coarse acquisition.
Is C/A the same as SPS? And is what you call "precise" the same as PPS?
Maybe to make my question more clear I should say is: do SPS and PPS still exist? |
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nej Frequent Visitor
Joined: Jun 16, 2004 Posts: 454 Location: London, Ingerlund
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Posted: Wed Jan 18, 2006 11:22 am Post subject: |
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JackS wrote: |
I think you mean coarse acquisition.
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Of course I mean coarse!
I've not heard of them referred to as SPS and PPS, however C/A and P-code signals are still seperate, so I just assumed that was what you meant. I can't imagine what else it would be. |
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