Hi Mike Alex (the gqrx and Gpredict author) suggested using pyephem to me once when I asked about this. I did have a little play with it, but haven't done anything interesting or useful.
http://rhodesmill.org/pyephem/ Darren, G0HWW On 24/11/14 10:15, Mike Willis wrote: > I know this is going back a bit but I would like to do the same thing for my > Gnuradio satellite ground station. I was actually tempted to compile satellite > tracking into a Gnuradio block. One you could simply use in a flowchart > without > any of the messing about with XMLRPC but like my new hexagonal wheel project, > with active compensatory suspension, it might be better to use what’s already > there. > > > > Did anyone do this? And, how difficult would it be in practice to develop a > native block that either contains predict, or accesses it? Possibly not very > difficult at all and maybe already done? > > > > Mike > > > > > > -------------------------------------------------------------------------------- > > On 22/07/13 12:31, M Dammer wrote: > > > > Is it possible to link Gnuradio and Gpredict ? I want to use Gpredict as > > tracker controlling the antenna position and to pass doppler corrected > > frequency data to Gnuradio. > > > > In a word, yes. > > > > Can be very simple. I did it by using an XML Server in the flow graph, > > and wrote a quick XML client (actually I "stole" most of it from an > > example), and sent the doppler info from predict via a variable. > > > > doppler info was received from predict using some code to query predict > > using UDP. I think I just used nc to send the UDP query to predict, > > recovered the shift from the reply, and sent it back to the XML Server > > running within the flow graph. > > > > Unfortunately I can't find my actual code right now, but I literally > > copied an example, and added the UDP Predict clients bit. It went > > something like this pseudo code (Yes, this is a mix of shell,and > > python, and you need to re-write the getting doppler from predict yourself, > but > you get the idea, and should give you enough) > > > > import time > > import sys > > from socket import * > > import xmlrpclib > > import binascii > > > > s = xmlrpclib.Server("http://192.168.39.74:8081" > <http://192.168.39.74:8081%22>;) > > infinite=1 > > while infinite == 1; > > # Grab predict doppler using UDP > > DOPPLER=`nc -u -s 2 $PREDICTHOST GET_DOPPLER $NORAD_NUMBER` > > s.set_doppler_shift($DOPPLER) > > time.sleep(1) > > > > The variable (lets call it doppler_shift) exists in the flowgraph, > > and was multiplied appropriately and applied to the centre frequency of > > a FIR filter. > > > > You can pretty much pass any information you want in and out of a flow > > graph using a XML Server/Client pair. I've done TX/RX switching, and > > am currently working on telemetry decoding/display > > > > > > Iain > > > > > > > > > > > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio