Tarver Engineering wrote:

"Peter" wrote in message
news:ruUYb.349212$xy6.1742195@attbi_s02...

Ron Lee wrote:

"Dave" wrote:



Unaugmented GPS is accurate to within 7.2 meters longitudinally.


Go say that in sci.geo.satellite-nav and see what happens.



Probably not a bad number.

Only if the usual caveats are added; i.e. 95% of the time and assuming the
receiver has good reception conditions. Any attorney trying to discredit
GPS evidence will naturally focus on the 5% of the time when the position
could be off by more than the nominal accuracy and on obstructions,
multi-path reflections, RFI, etc. that can degrade performance,
particularly in a covert installation where the antenna is unlikely to be
optimally placed for good reception.


False.

The convergence of the GPS Jacobian does not occur for the conditions you
describe. One of the major advantages of GPS over current ground based
navigation is the difficulty of spoofing the system.


I suggest you read your "GPS World" issues some more. Improvement of
integrity monitoring was one of the main reasons for requiring augmentation
of GPS. Evidence already presented in this court case also indicates
some of the problems cited above which resulted in momentary errors of
miles rather than meters.
I'm an advocate of GPS navigation but it is not infallible and carries no
absolute 7 m accuracy guarantee.