[CA] [CA11] Axiom 12 3D Vision goes sideways

[jfitch]

I've installed an Axiom 12 and RV212 transducers. There are numerous problems with it:

With the AHRS on, the bottom appears to spin in circles if you are moving.

With the AHRS off, the bottom appears to move at about a 45 degree angle to the boat's real motion.

AHRS either on or off, anytime the app is running there is a high probability of a crash and reboot.

The transducers are not mounted as far away from the engine and electrical cables as would be ideal, but this is a boat after all and there aren't that many choices.

The software and firmware are up to date. There is an autopilot networked to the system with heading sensor. There are two GPS units (external and internal to the Axiom) but it makes no difference which one is being used.

Questions: with AHRS off, shouldn't it be using the magnetic heading, or GPS COG to render the boat's motion over the bottom? How can that be 45 deg off? Both work properly in all other applications (chart, radar, etc.). How often does the AHRS need to be recalibrated?