[time-nuts] What position is measured?
magnus at rubidium.dyndns.org
Wed Sep 8 23:56:14 UTC 2010
On 09/08/2010 05:34 PM, Bob Camp wrote:
> Actually they do know a bit about the light delay. They include that data in
> the information the stat's broadcast. The data is fairly coarse grained. I
> posted some links a week or so back that go into all the grubby details.
Coarse grain is certainly a good way of saying it. The ionosphere
corrections are based on a simplification and then fitting data to the
model curve. The way to improve on this is to use DGPS sources such as
WAAS/EGNOS, which should be good enough for most timing purposes of the
Estimating ionospheric delay using dual frequency beats that. Still
leaves tropospheric delays thought. Reference network helps for that.
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