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Signal K data parsing
I am running OP2.5, have a GPS puck set up and have OpenCPN setup to send APB and RMB data back to signal K.  

I see many Signal K phrases parsed from the NMEA0183 RMB sentence (items 2, 6-12 from the list below), but I dont see one for Steer direction (item 3).  this component is also not parsed from APB.  what decides which parts of which sentences are parsed and How would I go about extracting that data?

RMB - Recommended Minimum Navigation Information[url=][/url]
To be sent by a navigation receiver when a destination waypoint is active.
       1 2   3 4    5    6       7 8        9 10  11  12  13|  15
       | |   | |    |    |       | |        | |   |   |   | |   |

Field Number:
  1. Status, A= Active, V = Void
  2. Cross Track error - nautical miles
  3. Direction to Steer, Left or Right
  4. TO Waypoint ID
  5. FROM Waypoint ID
  6. Destination Waypoint Latitude
  7. N or S
  8. Destination Waypoint Longitude
  9. E or W
  10. Range to destination in nautical miles
  11. Bearing to destination in degrees True
  12. Destination closing velocity in knots
  13. Arrival Status, A = Arrival Circle Entered
  14. Status A - Data Valid, V - Data Invalid, FAA mode indicator (NMEA 2.3 and later)
I would also be interested in calculating the ETA to next waypoint (/vessels/<RegExp>/navigation/courseRhumbline/activeRoute/estimatedTimeOfArrival) and the steer error (to go along with the Left or right steer direction)

ultimately, I would also like to calculate tidal drift using COG and GPS speed, vs heading and boat speed to be able to correct for the drift (corrected bearing to waypoint)

(2020-11-18, 10:43 PM)tkurki Wrote:

So I took a look at the nmea0183-signalk APB.js file and saw that 'direction' was already used in another phrase

 const direction = parts[3].trim().toUpperCase() === 'L' ? 1 : -1
but this would set L = 1 and R = -1, interesting

but I might need L and R
 // Direction to Steer
 const directionToSteer = parts[3].trim().toUpperCase() === 'L' ? "L" : "R"

I couldn't find a phrase for steer direction in the SignalK Documentation so I created one - not sure if this is OK?

           path: '',
           value: directionToSteer
           path: '',
           value: direction

and as such I have these two phrases ...direction and ...dirnum (direction number - not great) in signal K


I have attached the "APB.js" as a text file, just needs renaming, if anybody else wants to use it or make it available elsewhere?

I will work on adding the other items into Derived data

Attached Files
.txt   APB.txt (Size: 5.18 KB / Downloads: 4)
It may be I don't understand your goals with this but bear in mind you still have the origin "Direction to steer" flag in your changed APB. That's a negative XTE ('navigation.courseRhumbline.crossTrackError') value if direction is right and positive if left.
Thanks, didn’t think of that. I want to set up a simple page that has a sail gauge and then shows you how many degrees you need to steer right or left so I intend to setup two parameters that are steerErrorLeft and steerErrorRight and then have them displayed to the left and right of the page a keep the helmsman on course during racing. I could have done that by checking if the XTE was positive or negative

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