ADAHRS SV-ADAHRS-201 calibration

[skydancer]

My SV-ADAHRS-200 is on it's way to Dynon for repair (the magnetic heading was off > 60 degrees).

Today I recalibrated the SV-ADAHRS-201 in my RV-7, using the Airport compass rose and the Garmin-496 magnetic heading as reference.

I start the calibration from North--> East--> South--> West, then hit "save" to complete the calibration.

After the calibration, I checked the Skyview Compass Rose, I found only North and South were accurate enough, East was off for 10 degree (read 100*), West was off for 15* (read 285*). Then I recalibrated again, this time I started from East --> West --> North --> South.

After the 2nd calibration, all four directions came out to be within 1 degree from the reference. I test twice, both came out with the accurate reading.

Any of you experienced the similar calibration issue? how do you get the problem solved?

Dynon Tech support, how do you explain this phenomenon?

 

[dynonsupport]

So keep in mind that the "heading" that you're getting out of your 496 is based on ground track. So, you can't just spin around and have it work very accurately. You need to show it a considerably straight line so that it can use the lack of a change in direction to compute an accurate direction. In other words, you need to roll out in the direction that you're pointing if you're using a GPS track as your reference.

Can't say we've seen anything quite like this. I'll definitely run the scenario by our test team so that they can investigate whether there's any chance that the order matters (it shouldn't). But I'd guess that your alignment may not have been as dead on as you thought it was, especially if you were using the GPS like a compass.

 

[skydancer]

Dear Dynon,

Thank you for the reply.

I have very good sense of how to check the magnetic heading.

Like I said, I used both airport compass rose and garmin 496 for reference, and I did roll considerably straight line to stablize the GPS ground track. Both compass rose and GPS ground track turned out to be identical.

Once I get my SV-ADAHRS-200 back from you guys, I'll run another test and give you a full report.