Fancy satellite simulating hardware would be cool. In the interim,
there are a few software simulators we can try to feed out through a
HackRF. At the same time, it would be nice to try some other
correlators like the gnss-sdr code. And there are probably more tests
we can do with the simple
There was a request off-list for more background on this stuff, because
we're using plenty of jargon. One of the big goals for this group is
education, so I'm eager to help people understand what's going on. But I
don't want to answer questions privately, because I'm sure more people are
confused
For all you folks following along at home who want to see some pretty
pictures, here you go!
https://drive.google.com/open?id=1pnFV5MWkx5YR9ZlutetgDrejNG9SZx6Zp6xbdKl48Psauthuser=0
I sometimes have blissful moments of forgetting that Google wants all of
my data, always. In this particular
Interesting, good to know; although in this case it's a two-bit ADC
(literally and, perhaps, figuratively?), so it kind of doesn't have
low-order bits to dither. :-)
Considering that the noise floor is higher than the signal amplitude, you
could alternately look at it as being entirely dither,
Speaking of Doppler shifts, back when we were doing the GPS class we
were catching satellites at 10kHz Doppler using the recorded data we
found, and that really shouldn't be possible for a receiver at rest
(relative to the Earth surface).
I never looked into it further but i am suspicious of the
Awesome! And nice job on the pretty pictures!
I think this is strong evidence that we should get access to a real
satellite simulator, soon.
Though I don't understand why it saw a -14.8kHz Doppler shift. The original
file is a zero-IF sample. Did you set the HackRF at a center frequency
On Jun 3, 2015 7:44 AM, Kenny ke...@romhat.net wrote:
+ The STM32 which controls the MAX2769 (GPS baseband receiver) now
dynamically configures the MAX according to instructions received by
debug scripts so we can test all the configurations we want without
reprogramming the STM32 each time.
For generating pseudonoise, NOAA helpfully posted some Matlab code:
http://www.ngs.noaa.gov/gps-toolbox/MPsimul.htm
The bigger sample I took is only 196MB in raw I/Q sign/mag binary
format. But that turns into 3.1GB in complex 32-bit floats. I tried
compressing a few different ways:
3.1G
