Extending autopilot related paths 2020

This doc is a draft for extending Signal K autopilot related paths to improve integration with different autopilots/

List of relevant paths, proposed extensions in italic

• autopilot/state
  • enum: enabled disabled error
• autopilot/mode
  • enum: heading (compass), course (gps/courseOverGround), windApparent, windTrue
• autopilot/target/windAngleApparent
• autopilot/target/windAngleTrue
• autopilot/target/headingTrue
• autopilot/target/headingMagnetic
• autopilot/target/courseTrue
• autopilot/target/courseMagnetic (not really relevant?)
• autopilot/deadZone
• autopilot/backlash
• autopilot/gain
  • what subkeys should we have here?
• autopilot/maxDriveCurrent
• autopilot/maxDriveRate
• autopilot/portLock
• autopilot/starboardLock
• _ slew speeds ??_

"Navigation computer" related paths:

• navigation/courseGreatCircle/crossTrackError
• navigation/courseGreatCircle/bearingTrackTrue
• navigation/courseGreatCircle/bearingTrackMagnetic
• navigation/courseGreatCircle/activeRoute
• navigation/courseGreatCircle/activeRoute/estimatedTimeOfArrival
• navigation/courseGreatCircle/activeRoute/startTime
• navigation/courseGreatCircle/nextPoint {type + href}
• navigation/courseGreatCircle/nextPoint/distance (tkurki: no idea why these are missing)
• navigation/courseGreatCircle/nextPoint/position
• navigation/courseGreatCircle/previousPoint {type + href}
• navigation/courseGreatCircle/previousPoint/distance
• navigation/courseGreatCircle/previousPoint/position

Todo

• Dodging - what does it mean in real life?
• Tacking
• +/- adjustments
• • what well defined notification/* paths should there be?

Control vs informing about a state

In Signal K control/command is usually separate from "sensor data", eg. data about the current value of something. Control messages are HTTP PUTs or (ws) messages with put syntax: https://github.com/SignalK/specification/blob/master/gitbook-docs/put.md

Real World setups

How about describing some real world setups to get context and depth.

A start point would be current NMEA0183 and N2K systems and OpenCpn & pypilot, then we could construct a "pure" Signal K system.