Heading COG Mismatch (E125/ACU400/EV-1/P70/I70)

[lwitty]

Thanks Chuck, adding the photos for your reference.

In the photos, the COG is correct in both photos, heading seems to be the one that will get out of sync (display of heading data is incorrect and also is displayed incorrectly on E125, however, the AP steers the same course when the heading displayed changed by over 200 degrees).

As for SOG/speed, this occurs at any speed (sailboat so typically between 4-8 knts). Max deviation is 8 degrees and I have re-calibrated multiple times.

As for the fluid compass and COG/Heading, the COG is being reported accurately, heading is the one that is off. Once heading data "snaps out of its funk", the reading seems to be accurate and fairly well aligned with COG (with current, wind, etc being factored in).

I have 2 GPS sources, RS130 and E125. RS130 has great visibility with no obstructions to the sky. I have the data source set to "Auto" which seems to prefer the RS130. I have also manually switched to the E125 GPS and seen the same anomaly in the heading.

What I find strange is that I had the same behavior with the old S3/Fluxgate and the new ACU400/EV1. Seems the heading message is being corrupted somehow on the SeaTalk network.

anyway to capture diagnostics data while the error is occurring that may help? Any additional thoughts?