Compass ±30° off

[Donald E Robinson]

Yesterday, while setting up the Base and Triumph LS, I noticed that the LS's compass direction for north seemed to be too far to the right. I had just calibrated it, which I do regularly.

I got my handheld magnetic compass out and, sure enough, the LS was ±30° right of magnetic north.

Any Ideas why this is happening?

 

[Shawn Billings]

What's the declination there?

Might have just been a bad calibration. Did you attempt to calibrate again?

 

[Donald E Robinson]

What's the declination there?

Might have just been a bad calibration. Did you attempt to calibrate again?

No, it said it was successful the 1st time.

 

[Shawn Billings]

Could have been a bad calibration. After calibrating, I always point to the four quadrants. I turn it to the North as indicated by the compass in the collect action screen, then using the face of the LS to generally find a distant object at about 90°, I turn to the distant object and see if it is about 90°, then I repeat until I've looked at all four cardinal directions, looking for +/-5° (generally that's how close I can estimate 90° using the face of the LS). In my experience, when the calibration is bad, a quadrant is missing.

It could have been that you were too near magnetic influence when you calibrated. I'd just repeat it.

 

[Shawn Billings]

Another good check is to look at Base Rover Statistics white box and see what the R>B direction is. Then look at the compass. The R>B is a real time epoch by epoch direction, distance and vertical difference from the base to the rover.

 

[Sean Joyce]

Shawn, could this be taken a step further and calibrate the L.S. using those 2 points if in sight of the base?
After calibrating the magnetometer use the camera and point to the base as precisely as possible and calibrate Rover to Base..

 

[Shawn Billings]

I don't know that you'd see any improvement to the compass by doing this.

 

[Donald E Robinson]

I oriented the base station with my magnetic compass and disregard the LS North bearing. The points I surveyed appear to be in the correct location compared to previous points surveyed.

 

[Shawn Billings]

I don't think we're communicating. I'm not talking about orienting the base, I'm talking about the direction from the rover to the base. The base-rover statistics white box will give you this direction epoch by epoch in real time. Then you can sight, from the rover to the base, and see how the LS compass (or your magnetic compass) compares to the bearing given by base-rover statistics.

 

[Donald E Robinson]

I wasn't replying to your suggestion. I was just remarking what I did.

I'll check it next time I get it set up.

Thanks Shawn!