Kp-Index Calculation?

[beach]

Hello, it's this guy! I'm working on assigning a project for a fellow student in my school and I need help with it just a bit. The project is going to be calculating the "Kp" index of a system of 9 magnetometers from the THEMIS mission and comparing the index values to the Kp index that comes out of Boulder, Colorado. And this is where I'm stuck. I've found many different ways to calculate K-index such as using the total B-field and subtracting the minimum value from the maximum value in a 3-hour period, averaging the Bx and By field and doing the same from there, and then just using the Bx field and doing the same. But I don't know which of those methods Boulder uses because all they say on their summary is "horizontal components" and I've found other reports from students and other organizations using the aforementioned methods. So, help?

[Kevin VE3EN]

The relationship between K, Kp, and estimated Kp
The official planetary Kp index is derived by calculating a weighted average of K-indices from a network of geomagnetic observatories. Since these observatories do not report their data in real-time, it is necessary for an operations center such as ourselves to make the best estimate we can of this index based on available data. Space weather operations uses near real-time estimates of the Kp index which are derived by the U.S. Air Force 55th Space Weather Squadron. These estimated of Kp are based on a network of observatories reporting in near real-time. Most of the observatories are in North America, although there is one European station also contributing at this time (Hartland, UK).

www.swpc.noaa.gov/info/Kindex.html

[beach]

Well yeah, I don't mean to sound rude, but that is already known. I was more wondering of the lines of how they specifically calculate the Kp index and what mathematical steps are to create my own given 9 magnetometers which are around the nation and use that to compare to the USAF SWS Kp.