GPS Navigation great news
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GPS Navigation great news
The military uses "selective availability" within the GPS satellite broadcasts to make commercial GPS receivers less accurate than military ones. Well, thanks to Bill Clinton this accuracy-robbing feature is going to be turned OFF tonight!
My 2.7T doesn't have Nav, but I do have a GPS and I'm looking forward to seeing the accuracy improve by a big margin.
My 2.7T doesn't have Nav, but I do have a GPS and I'm looking forward to seeing the accuracy improve by a big margin.
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Might not make a difference
A lot of GPS receivers use components that are merely good enough for the accuracy provided by SA for commercial GPS. Many such GPS receivers will see minimal accuracy improvements because of these low-precision components.
Not to say that you won't see a difference, it all depends on how over-engineered your GPS receiver is.
Not to say that you won't see a difference, it all depends on how over-engineered your GPS receiver is.
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Re: Might not make a difference
Based on what I read at the link below, it should make a big difference indeed. Everything I've read about consumer GPS units is that they can easily handle the data once the SA is gone. The data is 'cleaner' now, they actually don't have to work as hard.
The link below leads to (among other things) information specifically about how it will affect auto navigation systems. Yesterday, yours could be off by 100m and tomorrow, it will be accurate enough to know what SIDE of the street you're on. It's supposed to take effect Midnight May 1.<ul><li><a href="http://www.igeb.gov/">Govt GPS site</a></li></ul>
The link below leads to (among other things) information specifically about how it will affect auto navigation systems. Yesterday, yours could be off by 100m and tomorrow, it will be accurate enough to know what SIDE of the street you're on. It's supposed to take effect Midnight May 1.<ul><li><a href="http://www.igeb.gov/">Govt GPS site</a></li></ul>
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Re: Might not make a difference
Turning off selective availability will make a huge difference in the accuracy of civilian GPS. SA introduces artificial timing errors into the GPS signals that civilian GPS recievers use and decreases the accuracy from about 15 meters to something like ten times more than that. The military (I'm an ex USAF pilot) uses a different set of signals, that were never effected by SA, and is able to get about 1 meter accuracy. To get even better accuracy (better than 15 meter)with your civilian GPS you will need to use a differential receiver which can bring accuracy to about a meter or with some surveying systems down to a few centimeters.
The reason that the USAF (which built the GPS system) added the SA errors was to keep an enemy from using our own GPS system for aiming missles and smart bombs. GPS was designed to be very difficult to jam but I believe that the US military has found ways to reliably jam GPS in selected areas so that the need to degrade the accuracy is not so great. Besides, with differential GPS available in so many areas the SA wasn't really providing the intended accuracy degredation anyway it was just making consumers buy more expensive equipment.
The reason that the USAF (which built the GPS system) added the SA errors was to keep an enemy from using our own GPS system for aiming missles and smart bombs. GPS was designed to be very difficult to jam but I believe that the US military has found ways to reliably jam GPS in selected areas so that the need to degrade the accuracy is not so great. Besides, with differential GPS available in so many areas the SA wasn't really providing the intended accuracy degredation anyway it was just making consumers buy more expensive equipment.
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Probably will require a softawre update
I don't know enough about GPS to comment on if the increased accuracy is usable by our current in car navigation systems. However, I suspect even if the signal is usuable it will probably require a software update before it will use the additional accuracy as part of the route display (the Lat/Long display shouldn't require an update to make use of the more accurate data).
The good news is that it appears the operating system can be updated via flashing from the CD-ROM that contains the map data, the bad news is that the operating system appears to be Windows (there is a config.sys file on the CD-ROM and references to .DLL and .EXE files).
marcos
The good news is that it appears the operating system can be updated via flashing from the CD-ROM that contains the map data, the bad news is that the operating system appears to be Windows (there is a config.sys file on the CD-ROM and references to .DLL and .EXE files).
marcos
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Re: GPS Navigation great news
All consumer GPS systems got much more accurate (including the factory Audi system) as of May 1st. There is NO firmware update required.
Selective Availability (SA) was an encoding scheme that allowed the government to add a random amount of error to the civilian GPS signals. They have simply decided to stop adding this error. It doesn't matter what firmware your GPS has or "how overbuilt it is". GPS is a digital system, if your antenna receives a signal at the correct strength or greater, it will be accurate.
More expensive GPS's have better antenna's (to receive weaker signals), multiple receivers (to acquire the required satellites faster), and in extreme cases... multiple antennas (which allowed them to defeat the SA).
As it turns out most of the Military uses civilian GPS units (instead of the more expensive military ones), so during Desert Storm, we actually turned off SA over the region!
The government can still add SA back and or turn off the civilian frequencies all together if the need arises.
Jason
Selective Availability (SA) was an encoding scheme that allowed the government to add a random amount of error to the civilian GPS signals. They have simply decided to stop adding this error. It doesn't matter what firmware your GPS has or "how overbuilt it is". GPS is a digital system, if your antenna receives a signal at the correct strength or greater, it will be accurate.
More expensive GPS's have better antenna's (to receive weaker signals), multiple receivers (to acquire the required satellites faster), and in extreme cases... multiple antennas (which allowed them to defeat the SA).
As it turns out most of the Military uses civilian GPS units (instead of the more expensive military ones), so during Desert Storm, we actually turned off SA over the region!
The government can still add SA back and or turn off the civilian frequencies all together if the need arises.
Jason