[time-nuts] GPS antenna length correction

"Björn Gabrielsson" bg at lysator.liu.se
Mon Apr 28 19:32:24 EDT 2014


> As mentioned earlier the position of the receiver is indeterminate unless
> the vector displacement from the antenna to the receiver is accounted for.
> Accounting for the cable delay will only correct the absolute time.
> Imagine a 100m antenna feed line; the receiver could be anywhere within
> 100m of the antenna (even above it or at it).  The algorithm that computes
> position
> needs to know this. It is possible the programmer assumes that the
> receiver
> is directely below the antenna; but I don't know what programmers assume.
> It would be safest to display the position of the antenna.  This
> discussion
> suggests that manufacturers should make it clear that the position is of
> the
> antenna or otherwise....

The receiver computes the position of the antenna phase center. The
position of the receiver is not of interest and also cannot be computed.
People who do not accept this, should keep their antenna cables really
short... ;-)

/Björn




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