Re: Getting GPS data into stream

2023-05-05 Thread Marcus Müller

Hi Fabian,
it's interleaved real, imag, real, imag. If you used dtype=np.complex64 instead of float32 
(and then not double the count), you'd get it interpreted exactly that way :)


Cheers,
Marcus

On 04.05.23 19:38, Fabian Schwartau wrote:

Sorry again, never mind... I found the problem.
The source code for reading the data does not include the fact that I am reading complex 
data and also three streams. Change the one line to:
data=np.fromfile(file=fh, dtype=np.float32, count=3*2*int(header_info['nitems']), sep='', 
offset=0)
and everything seems to work as expected. Now I just have to figure out how the data is 
ordered in that blob ;)


Best,
Fabian

Am 04.05.23 um 19:19 schrieb Fabian Schwartau:

Hi everyone,

I think I got hit by https://github.com/gnuradio/gnuradio/issues/5568.
Exactly the same error message. Is there any update on that issue or a 
workaround?
Attached are my files.

Best,
Fabian

Am 03.05.23 um 21:01 schrieb Marcus D. Leech:

On 03/05/2023 14:59, Fabian Schwartau wrote:

Sorry, forget it. Wrong sink...

You probably want:

https://wiki.gnuradio.org/index.php/File_Meta_Sink


Am 03.05.23 um 20:52 schrieb Fabian Schwartau:
OK, I think I found an easier way (at least for me), without having to write my own 
module - never done that.
I used the "Tags Strobe" block in combination with the "Python Module" for my 
gps_get_position() function.
Anyway, where can I find a definition of the format of the "Tagged File Sink"? I need 
to read this with antoher program, without gnuradio, but in python.


Best,
Fabian

Am 03.05.23 um 20:04 schrieb Marcus Müller:

Hi Fabian,

I'd write a block that copies a stream in- to output. It might query gpsd every time 
the work() function is called, or have a FIFO into which data from gspd is being 
pushed by a separate thread (or by reading from a socket or however gspd works, I 
must admit I'm not sure).


You then take that info, and encode the long, lat, uncertainty as (double, double, 
double) PMT tuple. You then use add_item_tag to add that PMT to the first sample in 
your output buffer.


You'd feed the result into a metadata file sink block: That saves things in a 
serialized format ready for retrieval.


Best,
Marcus

On 5/3/23 19:52, Fabian Schwartau wrote:

Hi everyone,

I am trying to record some data from an SDR and would like to sync/tag the data 
with the current gps position from gpsd. I am kind of stuck and don't know how a 
possible solution for that might look like in grc.
I have a python function that gets the current position as a tuple, but how do I 
get this into my data stream, which I would like to write to a CSV file or similar?

I am not asking for a solution of my problem, just point me in the right 
direction ;)

Best,
Fabian




















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2023-05-05 Thread Neel Pandeya
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