[time-nuts] What position is measured?

[Magnus Danielson]

On 09/08/2010 05:34 PM, Bob Camp wrote:
> Hi
>
> 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 
hobbyist.

Estimating ionospheric delay using dual frequency beats that. Still 
leaves tropospheric delays thought. Reference network helps for that.

Cheers,
Magnus