Taking Tau 2 - polarization time data in the PEV servo polarization time controller closed loop mode for the T2 curve fit equation for the Tau 2 feed forward open loop mode.
Build a Geomagnetic Observatory ! GELLER Labs "Backyard Science"
Thoughts on a proton precession magnetometer design - a Proton Magnetometer Project. Build an Earth's field magnetometer.
The FDM MAGNETOMETER1 project is a low cost high performance proton magnetometer (a digital magnetometer) kit under development for universities and amateur scientists to be able to accurately measure and monitor changes in the Earth's total magnetic F field and to observe geomagnetic storms. Magnetic storms can cause large excursions in the field and are of concern to interests ranging from electrical power grids, radio communications, and satellite operations, to aurora watchers and amateur radio operators.
1 Filter Diagonalization Method "FDM" (harmonic inversion), see Jan 21 and Jan 23 entries, based on: Vladimir A. Mandelshtam, Howard S. Taylor, Harmonic inversion of time signals and its applications, Journal of Chemical Physics (1997), Volume 107, Issue 17, 1997, Pages 6756-6769
(be sure to hit refresh to pick up our latest changes and entries)
Project Documentation, Links and References (very early stages)
Journal Notes:
Sunday, May 1, 2011
Overnight: PDF, TXT. The geomagnetic field remained unsettled to active overnight. The Tau 2 - polarization time curve continues to fill in well for a 0.85 V peak envelope voltage set point PDF. Early evening, the field continued to be unsettled all day PDF. Late evening/early morning: There was a >15 nT negative excursion in the field early morning PDF.
Monday, May 2, 2011
Overnight: PDF, TXT. The geomagnetic field was unsettled to active overnight. The field remained active today PDF.
Tuesday, May 3, 2011
Overnight: PDF, TXT. The geomagnetic field is still unsettled to active.
Wednesday, May 4, 2011
Thursday, May 5, 2011
Overnight: PDF, TXT. The geomagnetic field was relatively quiet overnight.
Friday, May 6, 2011
Saturday, May 7, 2011
Having now collected some data for the relationship between measured Tau 2 and polarization time using the peak envelope (PEV) servo mode, we change over for a while to the Tau 2 feed forward mode using the equation: polarization time = 0.214 * e^1.705. It will be interesting to see how the polarization time controller chart looks in the Tau 2 FF mode. For new readers, we measure Tau 2 (related to precession signal fall time) each measurement cycle. From Tau 2 we calculate the fluid temperature. In the Tau 2 feed forward mode, a polarization time is computed to give a desired peak envelope voltage. That is, we hold the precession signal peak amplitude relatively constant each measurement with changes in ambient temperature by varying the polarization time.
Sunday, May 8, 2011
Overnight: PDF, TXT. The NOAA Wing Kp model shows a lull in geomagnetic activity PDF.
The intial polarization controller plot for the Tau 2 feed forward (FF) mode looks good PDF. Since we are operating in the Tau 2 feed forward mode, the Tau 2 polarization curve predictably follows our feed forward equation PDF. The width of the Tau 2 polarization curve probably provides an indication of the variation in our Tau 2 measurement, since the polarization time to be used in each subsequent measurement is calcuated from a previous measurement of Tau 2. Also, there might be some small, but actual variation in the Tau 2 measured values caused by short term changes in temperature, interfering EMI/RFI signals, and the presently unknown noise floor of the Tau 2 measurment. The figure of merit (FOM) statistical mode (most common value) continues to run 2e-7 PDF with a large number of FOM values in the e-8 range.
Project Documentation, Links and References (very early stages)
QUESTIONS/COMMENTS/notice of typos, etc. send email to joegeller @ gellerlabs dot com
COPYRIGHT © 2009, 2010, 2011 JOSEPH M. GELLER, All rights reserved.