Re: Symbol timing estimator block and CPM modulations

[Nick Foster]

Thanks for the feedback, Andy! I'm back at this now. I've filed a bug on it with my findings so far. Comments welcome.

https://github.com/gnuradio/gnuradio/issues/3678

Nick

On Mon, Jun 29, 2020 at 1:06 PM Andy Walls <andy@silverblocksystems.net> wrote:

Hi Nick:

On Wed, 2020-06-24 at 17:39 -0700, Nick Foster wrote:
> Hi,
>
> I'm finally getting around to doing some more CPM work

I forgot to mention, my company found the GMSK demoulation technique
found in this paper:

https://www.researchgate.net/publication/241629765_Coherent_demodulation_of_AIS-GMSK_signals_in_co-channel_interference

coupled with the "method 0" CFO correction in this paper:

https://www.researchgate.net/publication/290776860_Preprocessing_AIS_Signals_for_Demodulation_in_Co-Channel_Interference

along with analog RF components in front of an SDR, and precise timing
with a GPSDO w/PPS to aid in looking for preambles, gave us fantastic
results for AIS reception in GNURadio.

Although it required quite a few custom blocks.

Anyway, Douglas Nelson seems to have a lot of cool papers available in the public:

https://www.researchgate.net/profile/Douglas_Nelson8

Regards,
Andy

> Best,
> Nick