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SignalK / specification

Signal K is a JSON-based format for storing and sharing marine data from different sources (e.g. nmea 0183, 2000, seatalk, etc)
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Navtex #356

Open joabakk opened 7 years ago

joabakk commented 7 years ago

Just a thought, should Navtex messages have a place in the specification?

sbender9 commented 7 years ago

I could google it. But might make sense to have the info here. What are Navtech messages?

joabakk commented 7 years ago

Sure: Navtex (Navigational Telex) is an international automated medium frequency direct-printing service for delivery of navigational and meteorological warnings and forecasts, as well as urgent maritime safety information to ships. It can look like this: `Navtex Bulletin Received (UTC): 2017-06-01 00:01:05

ZCZC AA84 310820 UTC MAY 17 COASTAL WARNING NOVOROSSIYSK 283 BLACK SEA

  1. GUNNERY FIRING EXERCISES 02 THRU 04 JUN FROM 0500 TO 1800 UTC NAVIGATION TEMPORARILY DANGEROUS IN AREA BOUNDED BY 43-27.0N 039-46.7E 43-30.0N 039-41.6E 43-31.4N 039-42.8E 43-26.7N 039-50.7E
  2. CANCEL THIS MESSAGE 041900 UTC JUN NNNN

A003`

toqduj commented 6 years ago

These are sent out regularly, and may be received using the same SDRs that we use for AIS data [edit: not true, had misconceptions about the frequency range of the common SDRs. Some more expensive ones like SDRplay will do, though]. I do not know of any useful demodulation libraries, however. Navtex is an essential part of the GDMSS and SOLAS regulations, and so is a good candidate for inclusion in SK.

You would also want to have flags for which message types / subjects you are interested in. Not all messages are of interest to all sailors.

More info: https://en.wikipedia.org/wiki/Navtex

joabakk commented 6 years ago

The regular SDR will not wok, as they are outside the frequency range. But using a device such as this https://swling.com/blog/2016/04/mikes-overview-and-review-of-the-40-soft66rtl3-sdr-by-kazunori-miura-ja7tdo/ and a method like this https://groups.io/g/linuxham/topic/4851931?p=,,,20,0,0,0::,,,0,0,0,4851931 might work. But hard and software solutions aside, I think it could be a valuable addition

toqduj commented 6 years ago

It would be a worthy addition, as I don't think there's any talk of phasing it out just yet.

I've been playing around with the SDRplay RSP2, but haven't managed to catch any navtex signals, let alone decode them.

mgrouch commented 3 years ago

There are decoders. Free and open source ones. Like this one:

https://arachnoid.com/JNX/index.html

There are also Inmarsat Fleet messages

And decoder:

https://bitbucket.org/scytalec/scytalec/src/develop/

I’ve built in them into BBN Marine OS https://github.com/bareboat-necessities/lysmarine_gen

mgrouch commented 2 years ago

Inmarsat-C decoder is here

https://github.com/cropinghigh/stdcdec

mgrouch commented 2 years ago

There is software to read NasaMarine NavTex receiver via serial usb

https://github.com/juerec/pc-navtex