4 ms·

Signal K – open-source universal marine data exchange format

82 points by pabs3 4y ago

msandford 4y ago
My only exposure is getting GPS and AIS data out of an OpenCPN computer and relayed to a tablet. Works great for that.
- pvaldes 4y ago
  Seems like a lot of regulation will stand in the middle of their path, and that will be adopted only by some sectors (No way military ships will pick this) but is intriguing. Security will be a problem.
  - emilecantin 4y ago
    Not sure what regulation you're talking about; the only existing standards in this space are either proprietary to one manufacturer (e.g Raymarine's Seatalk), or just industry consensus (e.g NMEA). There's no regulation enforcing the use of either except market forces. I know for a fact that security has been a big consideration in SignalK's development, but at its core SignalK is only a JSON schema; I don't see why military ships couldn't pick this up if they were so inclined. For now, it has basically become the standard in the open-source marine ecosystem; used by default in OpenPlotter (a marine-oriented Linux distribution) and supported in OpenCPN (a chartplotter/navigation software).
- mistrial9 4y ago
  OpenCPN needs a new maintainer in Debian --0 hint
pvaldes 4y ago
"allows for communication between instruments and sensors on board a single vessel, and also sharing of data between multiple boats, aids to navigation, bridges, marinas and other land-based resources"
- Jemm 4y ago
  So will be finally be able to find out a bridge's name without a cruising guide?
  - emilecantin 4y ago
    Sharing beyond a boat's internal network isn't much used yet except for a few use-cases. You need to have a way for the individual boats to share that data. The most obvious way would be to have access to the internet, and host a server somewhere where all the boats would send their data (sensor data, mostly position/heading/speed information). For example, a regatta could host a server where participants send all their data, enabling a live map with all participant's position and course plotted on it, along with depth & wind instrument readings. This could let spectators understand the participant's performance (how high their point into the wind, etc.) Navigation information (routes, waypoints, etc) can also be shared over SignalK, altough that's not much used yet as OpenCPN doesn't support it. Again, in the regatta example, you could see a "dynamic" regatta, where the course isn't known in advance. IMO the main challenge here is having a peer-to-peer "local broadcast" mode, like AIS or DSC. There are regulatory challenges with this, though.
    - pabs3 4y ago
      The more obvious way to share data at sea is radio, since it has less latency than out to the internet and then back and works when you aren't near land and don't have Starlink/etc. Is there really no protocol for this yet??
      - emilecantin 4y ago
        The "standard" radio on boats is the marine VHF, which is voice-only except for Digital Selective Calling (DSC). DSC is present on "newer" / more expensive radios so it's not a guarantee that a given boat has it. It has a few message types: - Distress calls - "Routine call" (basically rings the other boat and asks them to switch to a chosen channel so you can then talk over voice) - Position request There's very poor integration between these DSC messages and the rest of marine electronics. The other radio-based protocol is Automatic Identification System (AIS), which requires dedicated hardware (or a very expensive radio). It transmits your position, heading and speed regularly, and some biographic info (name & dimensions of the boat) from time to time. It's basically ADS-B for boats. This is very well integrated with all marine electronics and apps. It's also what powers sites like MarineTraffic. Main issue with both of these is that they aren't really extensible, so you can't send whatever you want over them. Other radio tech used on boats would be Single-Sideband (SSB), but that's more in the amateur radio realm. Some boats do have a full HAM setup, but it's not that common.
throw0101c 4y ago
So this is an alternative to NMEA (which is a variant of CANbus / SAE J1939)? * https://en.wikipedia.org/wiki/National_Marine_Electronics_Association#NMEA_OneNet https://en.wikipedia.org/wiki/National_Marine_Electronics_As... * https://en.wikipedia.org/wiki/NMEA_2000 https://en.wikipedia.org/wiki/NMEA_2000 * https://en.wikipedia.org/wiki/NMEA_0183 https://en.wikipedia.org/wiki/NMEA_0183
- Pasorrijer 4y ago
  Just an FYI, the first link (NMEA OneNet) sounds great, but isn't actually used by any of the major manufacturers yet sadly. Also, only NMEA2000 is based on CANbus, NMEA0183 is not.
  - floathub 4y ago
    Indeed. NMEA2000 is essentially a Marine Electronics version of CANBUS with their own agreed upon PGNs. NMEA0183 is pretty close to RS-232 (and/or RS-422), usually at 4800 baud, but there's a "High Speed" variant at 38,400 baud.
    - emilecantin 4y ago
      Minor nitpick: NMEA0183 is a text format (based on "sentences"), it's at the protocol layer, RS-422 is the most common transport layer but we often carry it over UDP or TCP too. SignalK can convert and output your data in NMEA0183 on TCP port 10110, for instance.
- yardie 4y ago
  It's not an alternative to NMEA, thought it definitely started as an open source replacement of NMEA. Cooler heads prevailed and the NMEA body opened some of the IP to SignalK developers. So instead of the opensource hardware that used SignalK as originally envisioned we have the same NMEA based proprietary hardware that SignalK ingest and convert to JSON.
Pasorrijer 4y ago
As someone with a boat, Signal K is super useful. It doesn't necessarily replace the other standards, but it means I can take my cats pajama's worth of other standards (NMEA0183, NMEA2000, homegrown Ethernet sensors) and ingest all of that data into one platform. After I've done that, it's really trivial to visualize it all in one place.
- BiteCode_dev 4y ago
  Given how terrible NMEA formats are, this is fantastic.
telecuda 4y ago
A $30,000 car today often has a far better screen/user experience than a $300,000 boat. iPad/tablet apps for boaters attached to mounts are common, though lack communication with the boat's sensors (without something like Signal K), and are hard to see in full sun. Compound that with the Coast Guard being a defense agency where getting new data typres in and out is "a process." Shameless but relevant plug -- I was annoyed hearing radio traffic of boaters trying to share their location with the Coast Guard, so I built a free tool for them (i911) that allows USCG to text the boater a link to share their location. The vast majority of distress calls are made within cell phone range (<15 miles from shore), so tapping that link isn't as much of an issue as you would think it is. It was the fastest tech to graduate from their R&D site to nationwide sector adoption. https://www.youtube.com/watch?v=QF1pi2-ygXU https://www.youtube.com/watch?v=QF1pi2-ygXU Excited to dig into Signal K to see if something there can help improve that response even further.

82 points by pabs3 4y ago

msandford 4y ago

My only exposure is getting GPS and AIS data out of an OpenCPN computer and relayed to a tablet. Works great for that.

pvaldes 4y ago
Seems like a lot of regulation will stand in the middle of their path, and that will be adopted only by some sectors (No way military ships will pick this) but is intriguing. Security will be a problem.
- emilecantin 4y ago
  Not sure what regulation you're talking about; the only existing standards in this space are either proprietary to one manufacturer (e.g Raymarine's Seatalk), or just industry consensus (e.g NMEA). There's no regulation enforcing the use of either except market forces. I know for a fact that security has been a big consideration in SignalK's development, but at its core SignalK is only a JSON schema; I don't see why military ships couldn't pick this up if they were so inclined. For now, it has basically become the standard in the open-source marine ecosystem; used by default in OpenPlotter (a marine-oriented Linux distribution) and supported in OpenCPN (a chartplotter/navigation software).
mistrial9 4y ago
OpenCPN needs a new maintainer in Debian --0 hint

pvaldes 4y ago

"allows for communication between instruments and sensors on board a single vessel, and also sharing of data between multiple boats, aids to navigation, bridges, marinas and other land-based resources"

Jemm 4y ago
So will be finally be able to find out a bridge's name without a cruising guide?
- emilecantin 4y ago
  Sharing beyond a boat's internal network isn't much used yet except for a few use-cases. You need to have a way for the individual boats to share that data. The most obvious way would be to have access to the internet, and host a server somewhere where all the boats would send their data (sensor data, mostly position/heading/speed information). For example, a regatta could host a server where participants send all their data, enabling a live map with all participant's position and course plotted on it, along with depth & wind instrument readings. This could let spectators understand the participant's performance (how high their point into the wind, etc.) Navigation information (routes, waypoints, etc) can also be shared over SignalK, altough that's not much used yet as OpenCPN doesn't support it. Again, in the regatta example, you could see a "dynamic" regatta, where the course isn't known in advance. IMO the main challenge here is having a peer-to-peer "local broadcast" mode, like AIS or DSC. There are regulatory challenges with this, though.
  - pabs3 4y ago
    The more obvious way to share data at sea is radio, since it has less latency than out to the internet and then back and works when you aren't near land and don't have Starlink/etc. Is there really no protocol for this yet??
    - emilecantin 4y ago
      The "standard" radio on boats is the marine VHF, which is voice-only except for Digital Selective Calling (DSC). DSC is present on "newer" / more expensive radios so it's not a guarantee that a given boat has it. It has a few message types: - Distress calls - "Routine call" (basically rings the other boat and asks them to switch to a chosen channel so you can then talk over voice) - Position request There's very poor integration between these DSC messages and the rest of marine electronics. The other radio-based protocol is Automatic Identification System (AIS), which requires dedicated hardware (or a very expensive radio). It transmits your position, heading and speed regularly, and some biographic info (name & dimensions of the boat) from time to time. It's basically ADS-B for boats. This is very well integrated with all marine electronics and apps. It's also what powers sites like MarineTraffic. Main issue with both of these is that they aren't really extensible, so you can't send whatever you want over them. Other radio tech used on boats would be Single-Sideband (SSB), but that's more in the amateur radio realm. Some boats do have a full HAM setup, but it's not that common.

throw0101c 4y ago

So this is an alternative to NMEA (which is a variant of CANbus / SAE J1939)? * https://en.wikipedia.org/wiki/National_Marine_Electronics_Association#NMEA_OneNet https://en.wikipedia.org/wiki/National_Marine_Electronics_As... * https://en.wikipedia.org/wiki/NMEA_2000 https://en.wikipedia.org/wiki/NMEA_2000 * https://en.wikipedia.org/wiki/NMEA_0183 https://en.wikipedia.org/wiki/NMEA_0183

Pasorrijer 4y ago
Just an FYI, the first link (NMEA OneNet) sounds great, but isn't actually used by any of the major manufacturers yet sadly. Also, only NMEA2000 is based on CANbus, NMEA0183 is not.
- floathub 4y ago
  Indeed. NMEA2000 is essentially a Marine Electronics version of CANBUS with their own agreed upon PGNs. NMEA0183 is pretty close to RS-232 (and/or RS-422), usually at 4800 baud, but there's a "High Speed" variant at 38,400 baud.
  - emilecantin 4y ago
    Minor nitpick: NMEA0183 is a text format (based on "sentences"), it's at the protocol layer, RS-422 is the most common transport layer but we often carry it over UDP or TCP too. SignalK can convert and output your data in NMEA0183 on TCP port 10110, for instance.
yardie 4y ago
It's not an alternative to NMEA, thought it definitely started as an open source replacement of NMEA. Cooler heads prevailed and the NMEA body opened some of the IP to SignalK developers. So instead of the opensource hardware that used SignalK as originally envisioned we have the same NMEA based proprietary hardware that SignalK ingest and convert to JSON.

Pasorrijer 4y ago

As someone with a boat, Signal K is super useful. It doesn't necessarily replace the other standards, but it means I can take my cats pajama's worth of other standards (NMEA0183, NMEA2000, homegrown Ethernet sensors) and ingest all of that data into one platform. After I've done that, it's really trivial to visualize it all in one place.

BiteCode_dev 4y ago
Given how terrible NMEA formats are, this is fantastic.

telecuda 4y ago

A $30,000 car today often has a far better screen/user experience than a $300,000 boat. iPad/tablet apps for boaters attached to mounts are common, though lack communication with the boat's sensors (without something like Signal K), and are hard to see in full sun. Compound that with the Coast Guard being a defense agency where getting new data typres in and out is "a process." Shameless but relevant plug -- I was annoyed hearing radio traffic of boaters trying to share their location with the Coast Guard, so I built a free tool for them (i911) that allows USCG to text the boater a link to share their location. The vast majority of distress calls are made within cell phone range (<15 miles from shore), so tapping that link isn't as much of an issue as you would think it is. It was the fastest tech to graduate from their R&D site to nationwide sector adoption. https://www.youtube.com/watch?v=QF1pi2-ygXU https://www.youtube.com/watch?v=QF1pi2-ygXU Excited to dig into Signal K to see if something there can help improve that response even further.