Why the wind instuments output MWV and not VMR

[BeMarek]

Hello,

I am scratching my head on this as to my understanding any wind measuring device, reads apparent wind. Now what I read from the several devices' guides the devices output MWV (wind speed and angle), not VMR (Relative Wind Speed and Angle) sentences. Anybody knows why? Or maybe I am totally wrong about that?

To the point ...

BTW: assuming I'd need some multiplexer do you think it is possible to send NMEA sentences to RPi to convert the sequence (what way?) and send it back to the multiplexer to output it to TP?

Thanks in advance for help and suggestions,

Marek