[Discuss-gnuradio] ais-tools-gnuradio problem

[A. Maitland Bottoms]

Jason writes:
 > I'm attempting to get the AIS receiver code from [1] working.

Me too.

Although I bypassed the mysql parts of the problem, and instead have
gnuradio receiving from a USRP to jack audio, and then connect that
to the standalone AIS decoder gnuais [2].

 > I'm pretty sure I have the date and time fields wrong...  Unfortunately,
 > I'm not receiving any messages to test if the DB is correct.
 > 
 > Any hints?

I am not successfully receiving and decoding messages yet either :(

But - one hint is that it might help to tune around. My USRP with
TV Rx is around 2kHz off. So tuning around has increased the rate
at which I see "Frame received OK.  170 bits" output.
Alas I also get "CRC Checksum FALSE!!!" a lot, too.

Once I do get binary data, I plan to process it with noaadata-py [3]
rather than Ruben Undheim's built in decoder.

 > Also, what antenna did you use?  How far from the transmitters?

In my case a hardware AIS receiver is hearing only one reporting vessel, as I
am not really close to much shipping here. That's making it a little
more challenging.

I also have yet to decode the sample data file
http://funwithelectronics.com/sdr/samples/ais1-250k.cfile.bz2
so perhaps I am not quite filtering and demodulating correctly yet.

-Maitland

 > [1] - http://funwithelectronics.com/sdr/ais.php
 [2] http://gnuais.sourceforge.net/
 [3] http://pypi.python.org/pypi/noaadata-py/