NMEA-0183 --MWV sentences

[amotl]

We discovered another software ¹ for the OpenWind devices that emits NMEA-0183 sentences using the $WIMWV identifier. Does it make sense to support it?

Example sentence:

$WIMWV,214.8,R,0.1,K

type iNMEAMWV struct {
  MWVId	string // $WIMWV
  WindAngle	string // 214.8 - 0 - 359
  TypeAngle	string // Relative - R True - T
  WindSpeed string //0.1
  Units	string // N - knots  - Kilometers/Metres/N Knots
  Status string // A = valid V = invalid
  Termination string // CR LF - 0x0D 0x0A
}

MWV - Wind Speed and Angle

        1   2 3   4 5 
        |   | |   | | 
 $--MWV,x.x,a,x.x,a*hh<CR><LF>

 Field Number:  
  1) Wind Angle, 0 to 360 degrees 
  2) Reference, R = Relative, T = True 
  3) Wind Speed 
  4) Wind Speed Units, K/M/N 
  5) Status, A = Data Valid 
  6) Checksum

-- http://www.nmea.de/nmea0183datensaetze.html#mwv

Footnotes

1. https://www.openwind.de/wp-content/uploads/2021/03/RaspberryPi.zip ↩

[amotl]

We are currently using VWR, which explicitly encodes "relative" wind data. /cc @UserMacUseface

-- http://www.nmea.de/nmea0183datensaetze.html#vwr

[amotl]

@UserMacUseface just shared those insights on this topic. Thanks!

VWR - Relative (Apparent) Wind Speed and Angle NMEA 0183 Sentences Not Recommended for New Designs Approved by the NMEA 0183 Standard Committee as of October 1, 2008 Wind angle in relation to the vessel's heading and wind speed measured relative to the moving vessel. The use of $--MWV is recommended.

-- https://web.archive.org/web/20220617080452/https://www.nmea.org/Assets/100108_nmea_0183_sentences_not_recommended_for_new_designs.pdf

In this respect, we think the NMEA broadcast message should be changed to use the MWV sentence identifier.