Here is an interesting discussion of Kalman filtering. http://math.stackexchange.com/questions/173901/why-use-a-kalman-filter-instead-of-keeping-a-running-average Thomas D. Erb tde@electrictime.com<mailto:tde@electrictime.com> / Electric Time Company, Inc. Office: 508-359-4396 x 117 / Fax: 508-359-4482 97 West Street Medfield, MA 02052 USA www.electrictime.com<http://www.electrictime.com> [Facebook]<https://www.facebook.com/pages/Electric-Time-Company-Inc/127918073950854?ref=hl>[Twitter]<https://twitter.com/tower_clocks>[pinterest]<https://www.pinterest.com/electrictime/> [htmlsig.com]<http://www.electrictime.com/>