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Raw GPS signal samples data set for testing GPS receivers.html
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Raw GPS signal samples data set for testing GPS receivers.html
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<p style="font-size:20px"><b>Raw GPS signal samples data set for testing GPS receivers</b></p>
<p>
3-Sep-2013
<br><br>
Raw GPS signal sample data can be a little hard to find on the net. Here is a 56 MB file containing about 77 seconds of data:
<a href="https://dl.dropboxusercontent.com/u/68809050/gps.samples.1bit.I.fs5456.if4092.bin"> gps.samples.1bit.I.fs5456.if4092.bin</a> [dropbox.com] <br>
It was copied and re-formatted from Michele Bavaro's excellent GPS blog, although the file is not there now:
<a href="http://michelebavaro.blogspot.com/2010_11_01_archive.html">
michelebavaro.blogspot.com</a>
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The parameters of the file are: 1-bit sign I-only data (not I&Q, not 2 or 3-bit sign & magnitude), bit-packed Little Endian (i.e. start with bit 0 of byte 0), sample rate fs = 5.456 MHz, IF = 4.092 MHz (i.e. not a zero-IF signal -- you have to mix (xor) with 4.092 MHz in addition to the C/A code). As Michele's post mentions if your decoding works you should get a lat/lon position in Nottingham, UK.
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I used this file as input to a software simulation I wrote of the FPGA tracking parts of Andrew Holme's wonderful homemade GPS receiver documented here:
<a href="http://www.aholme.co.uk/GPS/Main.htm"> aholme.co.uk/GPS
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Just using Andrew's FFT-based C++ search code alone immediately finds five signals:
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SV-0 PRN-1 lo_shift 6 ca_shift 1465 snr 108.7 <br>
SV-20 PRN-21 lo_shift 8 ca_shift 686 snr 121.7 <br>
SV-28 PRN-29 lo_shift -9 ca_shift 3868 snr 167.2 <br>
SV-29 PRN-30 lo_shift -9 ca_shift 2998 snr 145.2 <br>
SV-30 PRN-31 lo_shift -8 ca_shift 2337 snr 121.3
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