Sam Wormley wrote:
[...]
However the live introduction of the
new functions is causing problems wherein some of these receivers are
intermittently not tracking Y-code, and non-compliant civilian receivers
are also reporting continuing problems.

Sounds like some manufacturers didn't pay proper attention to the spec and
relied on something they should not have. Perhaps parts of the spec that
were unused until now were not implemented, or perhaps as Mike drew by
analogy the receiver relied on a part of the signal that was omnipresent but
not part of the spec.


Corrective action could encompass either the Air Force rolling back the
update or revising its software, or the manufacturers modifying GPS
software within the receivers to be totally compliant with the ICD.

In November and December 2009, the new software uploaded operational GPS
IIA and IIR space vehicles with navigation data and completed normal
operational functions. The software is part of the GPS modernization
effort, with its principal features being telemetry, tracking, and
commanding for the new GPS IIF space vehicle ? as yet unlaunched -- and
more robust security for the military M-code signal.

GPS only gives you position. Kinda narrows what the satellites can do unless
they go multi-purpose. I wonder what kind of position accuracy was expected
with the uprades.