Re: Differential correction in Africa

On Thu, 16 Jun 2005 09:24:33 +0200, Hans-Georg Michna
<hans-georgNoEmailPlease@xxxxxxxxxx> wrote:

>On Thu, 16 Jun 2005 03:09:33 +0200, "C.P Kurz"
><cpkXSPAM@xxxxxxxx> wrote:
>
>>Hans-Georg Michna schrieb:
>
>>> But the question arises how much better accuracy WAAS or EGNOS
>>> would yield outside the covered area. Since some of the
>>> corrections relate to global deviations, some improvement should
>
>>The question is more wether your reported EPE is in any way relevant. Not even
>>the ESTB RIMs receivers reach that accuracy, as can be seen from the ESTB
>>performance plots ...
>
>Preben, Carsten,
>
>I'm aware that the reported EPE doesn't mean much.
>
>I only wanted to know whether there is some real, global
>improvement with WAAS/EGNOS outside its target area.

<speculation>

With WAAS, your receiver will get better integrity information, and so can
discard bad satellite signals earlier. WAAS also contains clock and ephemeris
corrections, which should also apply globally. The ionospheric corrections
/might/ be useful for satellites low on the northern horizon. For the rest, it
all depends on the ionospheric model extrapolated over Africa, which might be
totally bogus or nonexistent (hopefully the latter). So the short answer is
that you can expect better integrity and better positions from the clock (+2m
max) and ephemeris (+2-4m max) corrections, as long as the possibly bogus
ionospheric corrections don't make thinks worse.

I expect the WAAS/EGNOS ionosphere model for Africa (if it exists at all) is
better than the one for northern Canada, which is also outside the WAAS target
area, but has much more severe ionospheric corrections to deal with.

</speculation>
.

Relevant Pages

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  • Re: Einstein and GPS
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