Re: [Discuss-gnuradio] Recording scarce AIS bursts

[Christian Gagneraud]

On 27/07/12 17:39, John Malsbury wrote:
> You may not see optimal performance, but the standard or simple squelch
> in GNU Radio may meet these basic needs.  I've used it for similar
> functionality in other packet radio systems.  I'm not sure what the
> "carrier on" time is before modulation starts, so I can't promise that
> they will work w/ the higher datarate of AIS.

Hi Nick,

It seems to do the job, at least it work for the strong bursts. Now i 
think i just need to find the right gain settings to get the weaker ones 
pass through.

thanks,
Chris


> Nick,
>
> Any thoughts?
>
> -John
>
>
>
>
> On Fri, Jul 27, 2012 at 8:40 AM, Christian Gagneraud <address@hidden
> <mailto:address@hidden>> wrote:
>
>     Hi list,
>
>     The problem with AIS is that if you are not in a busy place you
>     might have to wait for few seconds up to few minutes before a new
>     message comes in. Which is a bit annoying when you are doing live
>     experimentations.
>
>     I was thinking about recording only the raw message bursts, but i
>     would need a way to trigger the recorder such as to cut-off the
>     blanks in between the messages, but i didn't find yet a solution to
>     achieve that.
>     Would anyone have some tips to share on how to do that?
>
>     Another solution would be to record hours of data, and then apply
>     the same principle but off-line using a python script.
>
>     My triggering decision would be based on the signal level difference
>     at the carrier frequency and "outside enough" the carrier frequency.
>
>     Or maybe would anyone on that list have some "chatty" AIS data files
>     to share?
>
>     Chris
>
>     --
>     Christian Gagneraud,
>     Embedded systems engineer.
>     Techworks Marine
>     1 Harbour road
>     Dun Laoghaire
>     Co. Dublin
>     Ireland
>     Tel: + 353 (0) 1 236 5990 <tel:%2B%20353%20%280%29%201%20236%205990>
>     Web: http://www.techworks.ie/
>
>
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--
Christian Gagneraud,
Embedded systems engineer.
Techworks Marine
1 Harbour road
Dun Laoghaire
Co. Dublin
Ireland
Tel: + 353 (0) 1 236 5990
Web: http://www.techworks.ie/