Ais-tools-gnuradio problem

Sorry for the noise, my mailinglist alias was misspelled on this MTA,
resulting in some 550 sender verification errors. So, Ruben probably
has three copies of this… oops. :slight_smile:

Ruben et al,

I’m attempting to get the AIS receiver code from [1] working. So far,
I’ve gathered that the python code aisrcv-usrp.py receives the messages
and then aisgearthserver provides a kml file to google earth. The
problem I’m having is the mysql database is the middle. I took a stab
at creating it based on the insert queries in the code:

mysql> create table ais (
epoch int,
date TIMESTAMP,
time TIMESTAMP,
mmsi int,
latitude float,
longitude float,
coarse float,
speed float,
type int,
status int,
message VARCHAR(100),
coarse2 float,
name VARCHAR(100),
destination VARCHAR(100),
A int,
B int,
C int,
D int,
length int,
width int,
height int);

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?

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

thx,

Jason.

[1] - http://funwithelectronics.com/sdr/ais.php

Jason wrote:

Sorry for the noise, my mailinglist alias was misspelled on this MTA,
resulting in some 550 sender verification errors. So, Ruben probably
has three copies of this… oops. :slight_smile:

I was wrong. The 550 was from my dyndns mailhop service, so no one
received it. I should’ve just kept my mouth shut and no one would’ve
been the wiser. :wink:

Jason.

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 :frowning:

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 U.'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/

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