Template:Compasscalibration

Magnetic Error Correction (Calibration)

In order to get numbers of useful accuracy from the {{{1}}}'s compass you will need to provide calibration parameters. To make determining them easy, we distribute a program with our drivers that does this for you.

To calibrate your compass:

• Navigate to the Phidgets installation folder on your computer. Open the 'examples' folder and find the Compass Calibrator program.

• Start the program and find the link in the Settings/Status text box. Go to the website listed. (http://www.ngdc.noaa.gov/geomag-web/#igrfwmm)

• Select your country and city. Click 'Get Location' and then 'Compute'. A table of values will show up in an overlaid window. The value you will need is the 'Total Field' value in nT.

• Enter the magnetic field value into the calibration program. Note that it wants the field strength in Gauss, not nT like the website gives you. 1T = 10000 Gauss so you can convert easily enough.
• Depending on what your application is this step as well as the next step might be a bit different. If you are intending on mounting the {{{1}}} onto a large vehicle such as a car then you should mount the 1056 securely to the vehicle in its final intended position then check the 2-axis bubble, click the 'Start' button.
• If you are using a smaller, more easily handled vehicle such as a small robot (something you could physically pick up) you will mount the {{{1}}} and use the 3-axis calibration instead. Click 'Start'.

• Rotate the compass around (including whatever equipment you have mounted it to) such that the red dots being generated on screen outline as much of a full sphere (in 3-axis) as possible. This will take several minutes. Being perfect is not necessary but try to be as thorough as time permits. Once done, click stop.
• If you are in a large vehicle, you will be aiming to fill out a disc instead of a sphere. This can be done by simply driving around for a few minutes making sure to do complete $360^{o}$ turns in the process.

• Take the parameters displayed in the text box and use them for your compass. For example in C#:

 
     setCompassCorrectionParameters(0.51075, 0.18820, -0.07456, -0.02209, 1.87163, 1.87640, 2.12565, -0.04000, -0.04084, -0.03552, 0.09073, -0.04258, 0.11056);