Can anyone tell me what values I would have to use to find the magnetic field strength that the AD16488, and the AD16407 would have certain accuracies?

I am trying to calculate the extreme latitude that each of the devices can be accurate to within 2 degrees. I have all of the magnetic field strength information however I am having difficulties calculating the accuracy of the magnetometers given a certain field strength.

Thanks,

Rich

Hello Rich,

I apologize for the delay! I have been without a PC for 6 days and am just back online. We have a great IT team but they encountered a number of tough issues in upgrading my system.

The big thing about latitude is the horizontal component of the magnetic field which is used to calculate heading is continually diminishing as the latitude is increased. Thus any residual errors added to this horiz component of the magnetic field can result in a larger heading error as the latitude is increased. for the ADIS16488, we can envision a scenario where you can reach a total error of 4-5mGauss. This assumes a residual error of 1-2mGauss after a hard-iron correction (rotation) process, +/-10C change in temperature (Bias Tempco = 0.3mG/C) and some contribution for linearity. If we assume a residual error of +/-5mGuass and assumed a north pointing sensor, where the Y axis is pointing north and X axis point east, we would need a Y-axis magnetic field of 143 mGauss to preserve 2 degrees of error. This level of field is commonly associated with 50-60 degrees of latitude over most of the northern hemisphere. As one turns on the filtering and takes more care in calibrating out the hard iron effects then this number might improve slightly.

Y-Mag = 0.005 / asin(2 deg) = 143mGauss

We would expect the ADIS16407 to have 7-8mGauss of residual error, which would require ~229mGauss in the same scenario.

This level of field is more common at lattitudes of 30-40 degrees in the Northern Hemisphere. I hope that helps and again, I apologize for the delay.

y-Mag = 0.008/asin(2 deg) = 229mGauss

Best, NevadaMark