[teqc] TEC mesuarement

Evgeny Brainin ebrainin at gmail.com
Thu Jan 3 03:23:43 MST 2008


Thank you it was very helpful. Is the rate of change of TECU in time present
in *.ted files?

On Jan 3, 2008 12:16 AM, rocken <rocken at ucar.edu> wrote:

>
>
> This conversion comes from "Propagation Effects on Satellite
> Systems at Frequencies Below 10 GHz, W.L. Flock, NASA Reference
> Publication
> 1108, 1983" (section 2.3.1).  The units should be in TECU (1 TECU is
> 10**16 electrons / m**2)
> The conversion teqc uses assumes that the values in the .ion file are
> the ionospheric phase advance of the GPS L2 carrier in [m].
>
> Negative TECU numbers are possible because the teqc *.ion values are
> based on phase
> data and are biased by unknown carrier phase ambiguities.   Only the
> rate of change of the TECU values from teqc are meaningful - except for
> epochs when cycle slips affect the data.
>
> Chris
>
>
>
> On Jan 2, 2008, at 10:20 AM, Lou Estey wrote:
>
> > Evgeny Brainin wrote:
> >> Hi ALL
> >> I want to know how teqc calculate TEC (total electron content), by
> >> which formula? and why sometimes i get negative data of TEC?
> >
> > This option was just an experiment that we tried 11 years ago.  The
> > data in
> > the .tec file is just a simple rescaling of the .ion by:
> >
> > -(1227.6e6)^2/40.3e16
> >
> > where 1227.6e6 is the L2 carrier frequency in Hz.  I can't locate the
> > reference that comes from, but Chris Rocken (who is on this list)
> > should
> > know.
> >
> > At this point, the option should probably just be removed because I
> > think
> > it causes more confusion that any good that comes from it.
> >
> > cheers,
> > --lou
> >
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > Louis H. Estey, Ph.D.              office:  [+001] 303-381-7456
> > UNAVCO, 6350 Nautilus Drive           FAX:  [+001] 303-381-7451
> > Boulder, CO  80301-5554            e-mail:  lou  unavco.org
> >    WWW:  http://www.unavco.org   http://jules.unavco.org
> >
> > "If the universe is the answer, what is the question?"
> >                                                -- Leon Lederman
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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