<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">
<div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: 12.0px Helvetica">I read one paper that suggests any "jump" of 2 meters or more should result in an increase of the variance used in the Kalman Filter. However, I have seen my GPS module make jumps of 2 meters or more that was actually an improvement in the position estimate. So, it's hard to just say a "jump" by itself is either good or bad. You need to look at other factors. That's why I've been trying to find another way, like using inverse-number-of-satellites or HDOP as a gross approximation of the position error.</font></div><div><br class="webkit-block-placeholder"></div><div>!!Dean</div><div><br class="webkit-block-placeholder"></div><div><div>On Jan 29, 2008, at 13:00 , John Abshier wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Arial; font-size: 13px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; ">The discussions on filtering versus classification and use of a Kalman filter are interesting with respect to GPS errors. As mentioned above, GPS errors are correlated. But they often have large jumps when the satellites in use change. How should a filter handle the large jumps in position?</span></blockquote></div><br></body></html>