question regarding kalman filtering of IMU data paper by yadlin

[robotickalman]

for the past few weeks ive been reading up on the theory and operation of the kalman filter. one paper ive read that is extremely good can be found at http://www.usafa.edu/df/dfas/Papers/20082009/Attitude%20Determination%20and%20Bias%20Estimation%20Using%20Kalman%20Filtering%20-%20Yadlin.pdf

it discusses the know-how needed to implement attitude estimation using kalman filtering. im absolutely stumped as of now and im hoping that some of you guys can help me out.
 1. he uses an angular momentum term but did not say how he found it
 2. i did not understand how his F matrix was derived

i know that im being a bit unreasonable asking these questions but i believe that you guys possess the knowledge (and the generosity) to sort these problems out. thank you

[waltr]

There has been a few detailed discussions on implementing Kalman filters over on the SparkFun forum. Maybe the answer is there.