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Siggen · Guest

I have project which consists of calculating positions from RINEX o.
and n. files. I have searched the internet for formulas to use, but
haven`t got any good pages yet. Is there a good place where you can
find explained formulas? Will try to write those I already have here
(if they are correct):

P = phi + c*d_r-c*d^i

phi = sqrt([X^i(t-tau)-x_r]^2+[Y.....]^2+[Z.....]^2)

I would be happy for URLs or reference to PDF files to look at.

Thanks in advantage

Mr. Tillerli

Bob · Guest

Hi,

Calculating a position from RINEX files involves a few steps:

1- compute satellite clock bias (dt) (with ephemerides: coefficients
a0, a1 and a2)
2- compute time of transmission of signal for each satellite
(basically: t = t(reception) - C/Acode / speed of light - dt)
3- compute position of satellite at time of transmission (this involves
a few step using data from ephemerides - see reference later)
4- compute vector between approximate receiver position and satellites
5- least squares adjustment

I'm sure that what I just said didn't really help... the best ressource
for you would be a book on GPS (I know you could find algorithms for
all of the above mentionned steps in Leick's book). If you don't have
access to a library with GPS books, there is one online that is a good
start but you need to have a good Internet connection because it is
about 100 megs. Anyway, if you are interested:

http://gge.unb.ca/Pubs/LN58.pdf

Hope this was helpful

Bob · Guest

Hey, me again

if you don't want to write the code yourself, you can surely find it on
the internet. Her's an example:

http://gps.aau.dk/~borre/easy/

Sam Storm van Leeuwen · Guest

Hi,

Check my pages at http://home-2.worldonline.nl/~samsvl/software.htm

Have fun !

Sam

"Siggen" <sherstad@gmail.com> wrote in news:1134252956.239792.252900
@f14g2000cwb.googlegroups.com:

giSbjørn · Guest

Thanks for all the help! I am sure all of this information will help. I
have some books about GPS, but I will check out the book you gave me
Bob (luckily I can download it from my university - fast speed). I will
also check out the other links suggested, and if I remember it I will
post my finished applet in this same thread.

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