Magneto resistor based lightning storm detector 1

[capok]

Im doing a research on usage of Magneto resistors for identifying lightning stormy condition in the near surrounding of a aircraft by measuring electromagnetic flux in there. Iam going to develop prototype model for this one. Can somebody give some tips regarding the effectiveness of such a system?

 

[VEBill]

Aircraft would not generally be interested in the "near surrounding" of their aircraft. They'd like to know where the lightning is out at a distance of 200 miles, so that they have time to request a course diversion to go around it. There are so-called weather "radar" (no really) systems that rely upon the spectrum shift to guesstimate approximate distance, and two antennas to estimate bearing.

You should estimate the relative sensitivity of your proposed technique. I suspect that they'd hear the bang before your resistor would provide a useful signal. But it's up to you to do the sums. Good luck.

 

[VEBill]

Correction of typo: "...so-called weather "radar" (not really) systems..."

They're NOT really radar. Simply LF receivers.

 

[Skogsgurra]

An MR or GMR is typically an LF device that reacts to the H field. Given the rather short duration of lightning bolts and the rapid decay with distance that the magnetic field experiences, it is not likely that an MR or GMR can be sucessfully employed. A coil with wire will probably be a better choice and, as VE1BLL mentioned, the more effective detector is an antenna that is sensitive to the electromagnetic field, which travels a lot further without being attenuated.

Is there any particular reason why you chose to use an MR/GMR?

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[IRstuff]

Seems to me that you are a bit behind the technology curve. Aren't most commercial digital compasses using either fluxgate or MR detectors, like:

http://www51.honeywell.com/aero/com...alog-documents/Missiles-Munitions/HMR2300.pdf

I would think you would start with something like the HMR2300, but obviously the cost may be a bit much; it's around $600 for the cheapest model, but there are others that are cheaper:

https://www.sparkfun.com/categories/83

but obviously less capable. In any case, I would think a 3-axis magnetometer would be the minimum starting position, since you have to be able to sort out the magnetic interferences caused by the aircraft as well as variations in the Earth's field. You'd need a GPS for position, and Enhanced Magnetic Model 2010 (EMM2010) from NOAA:

http://www.ngdc.noaa.gov/geomag/EMM/

so that you'll know what the magnetic field is supposed to be doing.

If the typical compass magnetometer isn't sufficiently low in noise, then something like

http://magnetometer.com/wp-content/uploads/TFM65-VQS-FEBRUARY-2008-Spec-Sheet1.pdf

might be more apropos.

TTFN
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[VEBill]

The Earth's magnetic field isn't perfectly steady. It is sometimes disturbed during what are termed geomagnetic storms.

Also, the vector of the field as detected by a predominantly one-dimensional linear device would be a trig function of aircraft orientation. Thus, aircraft manoeuvrings would cause another signal. Time domain processing might reveal the sharp transitions of nearby lightning strikes.

 

[IRstuff]

that's why one needs to use something like the HMR2300, which is a 3-axis magnetometer.

TTFN
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