I was informed by an instructor of the Seamanship Course of the Canadian Power Squadron that the US Government re-introduced selective availability in their GPS Signals on or after 911. I have not heard of this before and cannot find a link to any suggestion that it happened. Does anyone know whether this allegation is factual? It was used as one reason why a seaman should never trust a GPS.
Selective availability.
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O C Diver
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Won't speak to whether a seaman can trust it (I do). Just curious what he thinks all the airplanes are using, same system. While the accuracy is exceptional compared to loran, one is still limited by the interface between the map on your plotter and your very accurate position from GPS. The ability to turn the system off or increase a substantial error, exist in the event of a pending missile strike. If it were to have been turned off or accuracy altered as a preparedness test, the accidental deaths associated with it, would have been headline news for weeks.
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Not true. SA has been turned off since the Clinton years.
Positioning has been improved in following years with WAAS and LAAS. A google search will explain those terms if you're not familiar.
Aviation systems depend on accuracy and have become more dependent on GPS each year. The 3D positioning accuracy is integral to the use of RNAV approaches and some departure procedures.
Wide areas of GPS signal jamming by the military and industrial testing are commonplace. These are normally made public through Notices to Airmen.
Positioning has been improved in following years with WAAS and LAAS. A google search will explain those terms if you're not familiar.
Aviation systems depend on accuracy and have become more dependent on GPS each year. The 3D positioning accuracy is integral to the use of RNAV approaches and some departure procedures.
Wide areas of GPS signal jamming by the military and industrial testing are commonplace. These are normally made public through Notices to Airmen.
Donsan
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Urban legend.
What I have read is SA was removed from future satellites starting in 2007 or 2008.
What I have read is SA was removed from future satellites starting in 2007 or 2008.
FF
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"Wide areas of GPS signal jamming by the military and industrial testing are commonplace."
And many bars and truck stops as drivers do not want the boss to know their location.
And many bars and truck stops as drivers do not want the boss to know their location.
Instructor changed position.
The Canadian Power Squadron instructor changed their position saying that although it was discussed selective availability was never re-introduced on or after 911. I guess that means I don't have to throw my GPS chart plotters overboard.
The Canadian Power Squadron instructor changed their position saying that although it was discussed selective availability was never re-introduced on or after 911. I guess that means I don't have to throw my GPS chart plotters overboard.
MYTraveler
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It would make sense that they retained the capability to quickly turn it on in appropriate circumstances.
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The new birds have separate signals for military and civilian. I think the separate band intent is not for turning it off so others can use, but to keep the military signal from bring jammed. GPS III is way behind schedule.
Supposedly the new satellites don't even have SA capability anymore.
I find my GPS gets a quicker fix from the stronger signal strength if the Glossnas satellites.
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