[CA] [CA11] GPS Sentences required by ST4000+ ?

[davemi]

This question will likely require some knowledge of the firmware running on the ST4000+ processor.

I am trying to understand which of protocol "sentences" are used, needed, and ignored by the ST4000+ at the NMEA(+/-) inputs which go to the optoisolator level-shifter on processor board.

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The manual states: The following NMEA 0183 wind and navigation data can be decoded by the ST4000 Plus.
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Course Over Ground VTG, RMC, RMA
Speed Over Ground VTG, RMC, RMA
Cross Track Error APB, APA, RMB, XTE
Bearing to Waypoint APB, BWR, BWC, RMB
Distance to Waypoint BWR, BWC, RMB
Waypoint Number APB, APA, BWR, BWC, RMB
Apparent Wind Speed VWR, MWV
Apparent Wind Angle VWR, MWV
Speed Through Water VHW
Depth DBT
Water Temperature MTW
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The GPS device I have supplies GPRMC, GPVTC, and others not listed as decodable such as GPGGA, GSA, GSV and GLL.

Question#1: Will the ST4000 Plus be able to parse the data for $GPRMC and $GPVTG and ignore (no errors) the others not listed as decodable from my GPS receiver (GPGGA, GSA, GSV and GLL)?

Question#2: If "Course Over Ground VTG, RMC, RMA" is listed with these three formats in the manual, does the ST4000+ need all three or even two? Will it work using RMC and VTG only, which is what my GPS reciever will supply in the NMEA 0183 format running at 4800 baud, 8 data, 1 stop, no parity, no handshake?

I hope I've been clear. Let me know if I can give additional detail.
Thanks -Dave

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Dave,

Q1: Will the ST4000 Plus be able to parse the data for $GPRMC and $GPVTG and ignore (no errors) the others not listed as decodable from my GPS receiver (GPGGA, GSA, GSV and GLL)?
A1: From the standpoint of using the autopilot's Track mode, Please click here to view a FAQ addressing this subject.

Q2: If "Course Over Ground VTG, RMC, RMA" is listed with these three formats in the manual, does the ST4000+ need all three or even two? Will it work using RMC and VTG only, which is what my GPS reciever will supply in the NMEA 0183 format running at 4800 baud, 8 data, 1 stop, no parity, no handshake?
A1. See the FAQ referenced within the response to Q1. The MFD is seeking data, not necessarily a specific NMEA 0183 sentence and certainly not every one of the listed NMEA 0183 sentences. Should you search the internet for NMEA 0183 protocol, you may find list of which data items are included within each sentence. Naturally and additionally, should the autopilot need to steer to wind then a NMEA 0183 sentence containing apparent wind data will need to be supplied to the autopilot.