Why do I have two different speeds over ground?
See this screenshot. I have an em-trak AIS connected over USB and no other devices. Why does Signal K receive two different speeds? What do the words AIS.AI and AIS.GN mean?
![No description](https://cdn.answeroverflow.com/1234545036453089405/image.png)
7 Replies
You are receiving two different NMEA0183 sentences VDO and RMC with different talker Ids AI and GN
@Ansis you need to either, configure source priority rules in SK or, ensure that you manually get the value from a specific source
Sounds like they have actually only a single source device, in that case this does not really matter
I’m curious about this @Teppo Kurki , aren’t AIS.AI and AIS.GN different sources?
In SK they are. What are you asking?
All sk sees is the data that in this case has messages AIVDO and GNRMC, using two different talker ids. Are they one device or two independent devices in real life? Can’t tell from the data. 0183 input may have data from one or several, if there is a multiplexer
I was just curious about the device ID. Oh I see. Thanks for the explanation
FYI, updating to the latest version of signalk-server made the AIS.GN (RMC) entries go away.