Article: 90666 of sci.geo.satellite-nav
Message-ID: <36B7A41D.7C8F4C50@illgen.com>
From: Jeff Valine <jvaline@illgen.com>
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Subject: Re: GPS Navigation Message Samples
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For your amusement...

I have placed about 2.5 hours worth of data at:
http://table.jps.net/~jvaline/gpsdata/gps_subframe_dump.zip

The file is about 1.1 MB zipped, but about 11 MB unzipped.

This data is a text file that is the output of an in-house dump
utility.  It has both the input 300 bits, and the decoded & scaled
engineering units for all the data in each of the subframes.  

The raw byte stream is displayed in hex on a single line that looks like
this:

GPS frame = 8B 0E C8 32 FD 4A A7 CB 2F 2E E4 0C 8A 17 C4 F7 7F A7 8C 2C
7F EB C3 E3 74 0C 7B 3D 97 82 0C FA 44 1D BF 73 28 40 

This is followed by the decoded data:

24-bit data words & corresponding 6-bit parity:
 8B0EC8 0C BF52A9 3C B2F2EE 10 32285F 04 F77FA7 23
 F4E005 3C 3E3740 31 1309A1 02 0CFA44 07 902335 04
Preamble = 8B
TOW = 587742
Alert Flag = 0
AS Flag = 1
Subframe ID = 2
Subframe 2, Ephemeris Data, Part 1
IODE = 178
Crs = -104.562 meters
del n = 1.45974e-09 semicircles/second
M0 = 0.741928 semicircles
Cuc = -5.30481e-06 radians
e = 0.0102403
Sqrt(A) = 5153.62 sqrt(meters)
Cus = 9.07667e-06
Toe = 590384 seconds
Fit Interval Flag = 0, Curve Fit = 4 hours

Please, I'm providing this data with absolutely no guarantees as to
correctness or validity.  Have fun.
-- 

Jeff
jvaline@illgen.com


Luis Javier Reina Tosina wrote:
> 
> I don't know if this would be the best newsgroup to ask this question, but I
> am interested in developing low-level software for GPS receivers. I would
> like to access some samples of navigation message raw data to check the
> software before applying it to the hardware.
> 
> Does anybody know where can I find a site with archives containing
> non-processed samples of Navigation Messages from different satellites?
> There are some interesting sites, but all of the ones I have explored use
> formatted pseudorange and ephemeris data, or incomplete subframe sets.
> 
> Thanks in advance for your attention.
> 
> Javier