Re: [Discuss-gnuradio] GPS on DBSRX

[Trond Danielsen]

2007/5/24, Ben Loftin <address@hidden>:
> Trond,
>
> > If anyone is interested, I have a complete coarse acquisition module
> > written for GNU Radio. The source code is available from
> > http://code.google.com/p/opengnss/. Some cleaning of the code is still
> > required. You can find images of the current results here:
> > http://trondd.blogspot.com/2007/05/opengnss-status.html
>
> Awesome, I would like to try it out, what is the best way to get the needed
> blocks assuming they are not in a patch already?
>
> Any thoughts on the next step of tracking?

I want to try both the BASS tracking described by James Bao-Yen Tsui
in Fundamentals of Global Positioning System Receivers: A Software
Approach and a conventional PLL based tracking module.

But before I can get down to tracking, I have to implement the fine
frequency estimation.

> Also, if I want to test it from my captured files would I change line 85 of
> acquisition.py to pull from a file or is this done somewhere else.  Thanks.

Take a look at the gr_gnss-acquistion-test.py script in the scripts
folder. Basically this is all you need:

       file_src =  gr.file_source(gr.sizeof_gr_complex,
"../data/L1-4MHz-svn1-nav.dat")
       self.acquisition = acquisition(fs=fs, svn=1, alpha=alpha)

       self.ca_sink = gr.vector_sink_f()
       self.fd_sink = gr.vector_sink_f()
       self.rmax_sink = gr.vector_sink_f()

       self.connect( self.src,  self.acquisition)
       self.connect( (self.acquisition, 0), self.ca_sink )
       self.connect( (self.acquisition, 1), self.fd_sink )
       self.connect( (self.acquisition, 2), self.rmax_sink )

--
Trond Danielsen