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Compass Reading near North Pole

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    Bolek Mellerowicz

    How does the geographic location e.g. near the Equator vs closer to North Pole affect the the heading readings (compass reading) of the UM7 sensor? Specifically I need to use this sensor up North in Summit, Greenland to measure the angular position as a regular compass would.

    I am afraid that because the horizontal intensity is about three times less the UM7’s compass reading may not be reliable Is there a min. Horizontal Intensity the sensor requires to function (assuming calibraton and no hard iron distortions)?

    NOAA has a magnetic field calculator see link below and I used it to compare the magnetic fields in Los Angeles vs Summit, Greenland.

    Declination = -28 deg
    Inclination = 81.1 deg
    Horizontal Intensity = 8400 nT
    North Comp. = 7400 nT
    East Comp. -3990 nT
    Vertical Comp 54000 nT
    Total field = 54700 nT

    Los Angeles:
    Declination = 13 deg
    Inclination = 58 deg
    Horizontal Intensity = 24300 nT
    North Comp. = 23800 nT
    East Comp. 5100 nT
    Vertical Comp 40100 nT
    Total field = 46900 nT

    Magnetic Field Calculator

    Thank you,



    Hi Bolek,
    This is a very interesting question I have had similar thoughts about using the sensor at the equator, but thats another story.

    To be safe I think you should calibrate your unit in the local magnetic surroundings, and the sensor should operate as specified.
    Are you able to perform Calibration on site, or are these being deployed from a test platform, and delivered to the area you mentioned?

    However the UM7’s only limitation is the sensor itself, its sensitivity is ±4800 uT at full scale range.
    so this gives the sensor about (9600 uT/ 2^14 bits) = apx 585.98 nT resolution.

    However the figures you have posted look within these values, so I don’t think this would be an issue.

    Michael Malloy

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