Sensors for detecting nT fields (ie: deviations in the earth's natural magnet field)

deef, Fri Jan 16 2009, 12:48AM

Hello,

I was just wondering if anyone had any experience with sensors that are capable of detecting magnetic fields down to the nT level (eg: 25nT, or somewhere around there). Essentially, I'm looking to differentiate between deviations in the earth's natural magnetic field, and the non-deviated (or undisturbed) magnetic field produced by the earth.

In other words, it's for object detection. I wish to take advantage of the changes induced upon the earth's natural magnetic field to determine whether or not an object is in the path of this sensor.

I've found some products manufactured by a company called PNI, but I was interested if anyone had a favourite manufacturer for these sorts of good. Here's what i've found so far: I'd be interested in similar statistics to the sensor i've given as an example (bandwidth, resolution, precision). Obviously the more samples per second, at the nT level, the better. I already know i'm going to be doing a load of filtering and DSP.

I really appreciate your help!

Thanks.