What magnetometers are out there?

Mar 27, 2007 2 Replies

Hi - I'm working on building a fairly sophisticated IMU system. It will combine data coming from 3 axes of gyro, 3 axes of accelerometer,



3 axes of magnetometer, and a DGPS corrected GPS into an XYZ offset and roll pitch yaw offset from initial conditions.

Anyways - right now I'm trying to identify what sort of magnetometer to use. I care most about accuracy, precision, and bandwidth. Right now I'm thinking I'll use some Honeywell parts:

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- probably the HMC1053:
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Good linearity (.1%), high bandwidth (5MHz), small size (LCC-16 (essentially a QFN without a ground pad)), annoying interface (lots of external parts needed - including high voltage stuff - a complete pain to work with).



One thing I worry about a bit - Honeywell also has some parts with 3x the sensitivity of the HMC1053, but in unappealing packages (and only single or dual axes). Will I lose any accuracy by having to set my gain 3x as high on whatever instrumentation amp. I use? From my understanding typically the non-linearity of instrumentation amps is in the hundreths or thousandths of a percent, so it won't matter at all.



PNI make some sensors that seem to be more bandwidth limited. Various other companies make magnetometers with somewhat slow digital interfaces, whereas I'm looking for an analog interface. I would like about 1KHz bandwidth or more.



Any other parts I should be looking at?



Thanks!


-Mike



We are working on

and

Absolute position to 10cm.

Both requires MicroElectroMechanicalSystem (MEMS) fabrication parts. We just need to find the right company to do it for us.

Why would you need MEMS for GPS? What's mechanical about GPS?

Also, relying entirely on accelerometers and GPS will certainly limit you to where your device can be used. I'm not sure what market such a device would appeal to - needing a nearby DGPS station as well as a good satellite signal. What market are you aiming at?

-Mike

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