[time-nuts] GPS usable for weather forecasting?

Poul-Henning Kamp phk at phk.freebsd.dk
Sat Mar 30 00:51:24 EDT 2013

In message <5156611D.6090201 at earthlink.net>, Jim Lux writes:

>occultation is pretty heavily used now.. When you talk about weather 
>forecasting, they talk about "what percentage of the variance is reduced 
>by adding source X", and I seem to recall that for GPS RO it's something 
>like 10-15%.. around the 3rd or 4th most useful measurement.

>Also, that whole "stated needs" is a pretty fuzzy thing. [...]

Isn't it always ?

They have a point though: LEO data of all kinds pretty much king
in global weather models these days.   ECMWF has a very interesting
artile on page 5 in their latest newsletter:

    "Polar-orbiting satellites crucial in successful Sandy forecasts."


>Keeping this somewhat time-nutty... It would be interesting to see what 
>kind of measurement performance one could get with cheap GPS receivers 
>like they use on cubesats.

The Ørsted satellite used a standard Turbo-rogue receiver in in a
high output-rate mode.  Can't remember if it was 10 or 100Hz.  I
seem to remember that dual-frequency carrier tracking is the enabling
technology for GPS sounding, but the Øersted papers will give
you all that.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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