On 4/6/15 2:14 AM, Attila Kinali wrote:
Moin,
On Fri, 03 Apr 2015 22:51:34 -0500
Robert Watzlavick <[email protected]> wrote:
On 04/03/2015 10:12 PM, Robert Watzlavick wrote:
I have an amateur radio license (mostly CW/HF and some VHF/UHF
experience) and I've written some driver software for an IQ
demodulation board but I have to admit, I would have no idea how to
begin setting up that system as initially described by Attila and
expanded by you and others. I have a rudimentary understanding of the
modulation schemes involved but I don't fully understand how the
various codes mentioned fit in. I've poked around a bit at some
articles on PN codes and I can see how data would be transmitted but I
think I'm missing something key that allows you to extract positions,
velocities, etc. out of the various links. I think I have some more
reading to do :)
The basic system is that of an DSSS modulator/demodulator.
The best text on spread spectrum systems I have found sofar
is [1]. I explains modulation and demodulation in a hands on
fashion. But, due to the age of the book, it does not contain
any of the advanced stuff done today. But I think you don't need
anything more fancy than an early-prompt-late correlator architecture
for tracking.
Actually, if you're post processing, you can just record raw bits and do
the correlation in software. You don't really need to track it in real
time. Although, that might not be a bad way to do it.
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