Nav System - Can it be adjusted?
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From: Boston, MA.
Maybe the current administration has enabled "Selective Availability" again for National Security, so terrorists can't use GPS for weapons (see info below). 
The early American GPS system was programmed to generate false data by the receiver. This error was called "Selective Availability" and would result in GPS coordinates that were a few hundred meters off of true coordinates. This slight error was programmed into the satellites so that, without a compensating device capable of correcting for the error (typically a military device), the GPS would produce false data that was not accurate or reliable for a given spot. Selective availability was turned off in 2000, following a 1996 executive order mandating that users receive a non-degraded signal globally. The feature still exists and/ can be re-enabled at any time.
The early American GPS system was programmed to generate false data by the receiver. This error was called "Selective Availability" and would result in GPS coordinates that were a few hundred meters off of true coordinates. This slight error was programmed into the satellites so that, without a compensating device capable of correcting for the error (typically a military device), the GPS would produce false data that was not accurate or reliable for a given spot. Selective availability was turned off in 2000, following a 1996 executive order mandating that users receive a non-degraded signal globally. The feature still exists and/ can be re-enabled at any time.
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Originally Posted by hinckley' post='519136' date='Jan 17 2008, 11:34 AM
Please post or pm me with the results.
One thing that I've thought about is that I seem to remember the 04 nav moving from 50 to 40 to 30 to 20 to 10 feet. My 08 goes from 100 to 50 to 0. If I'm right about that, it may explain why when stopped on a stop line, the nav system still shows the intersection as 50 feet away. But, I'll tell you, I'm often at that stop line with the nav system showing the intersection as 100 feet away. And unless you're crossing a six lane highway, 100 feet is a long way away. It's frustrating - I've been at multi-point intersections where I've picked te wrong turn more than once.
Can anyone out there comment on whether the older nav cars/software calibrated in 10 feet rather than 50 feet increments?
One thing that I've thought about is that I seem to remember the 04 nav moving from 50 to 40 to 30 to 20 to 10 feet. My 08 goes from 100 to 50 to 0. If I'm right about that, it may explain why when stopped on a stop line, the nav system still shows the intersection as 50 feet away. But, I'll tell you, I'm often at that stop line with the nav system showing the intersection as 100 feet away. And unless you're crossing a six lane highway, 100 feet is a long way away. It's frustrating - I've been at multi-point intersections where I've picked te wrong turn more than once.
Can anyone out there comment on whether the older nav cars/software calibrated in 10 feet rather than 50 feet increments?
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My Ride: 2008 Space Gray 550i, Light Poplar Wood, Anthracite Head Liner, Sport Package, Sport Automatic Transmission, Cold Weather Package, Front Ventilated Comfort Seats in Black Nasca Leather, NAV, HUD, Active Steering, Comfort Access, Night Vision, Lane Deviation Warning, Active Cruise Control, Heated Rear Seats, Folding Rear Seats, Power Shade w/ Rear Side-Shades, Rear Air Bags, Logic 7, HD Radio, Sirius Satellite Radio, iPod/USB Adapter. Car in BMW Body Shop, estimated completion 01/24/07.
My 01/02/08 build 550i is very accurate, within 10-15 feet most times.
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