[time-nuts] GPS antenna length correction

[Michael Perrett]

The ability to correct the position depends on the receiver. Some receivers
have a correction known as the lever arm correction. This is the vector
difference between the antenna centroid and there is also a variable to
enter the cable length. Between these two corrections the receiver time and
position is the same as that at the antenna centroid.

These corrections are normally found on kinematic and military receivers
but may be on any - check the specs / owners manuals.

Michael / K7HIL


On Mon, Apr 28, 2014 at 8:20 AM, Hal Murray <hmurray at megapathdsl.net> wrote:

>
> brian at lloyd.com said:
> > As I think about the geometry of satellite position and path length, it
> > seems to me that, since the geometry is determined by the antenna
> position
> > and not the receiver position, additional antenna cable introduces a
> fixed
> > delay value and hence a fixed constant that gets added to each path
> > regardless of direction. It seems to me that this would produce a much
> > "fuzzier" solution to position and/or variation in timing. Knowing cable
> > length and propagation velocity, would allow the software to subtract
> that
> > constant from all ranges and thus provide a more correct position and
> time
> > solution. Is this not the case? Does it do something simpler but "good
> > enough"?
>
> If you just do the normal calculations, you get the location of the antenna
> as though you were there a while ago.  If you know the delay in the cable,
> you can correct the time.  There is no way to correct the position.
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
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