GPS "Tracks"
While in motion, many GPS units are able to maintain real time "tracks" by dropping electronic breadcrumbs into the stored data. Assigned at time intervals, these breadcrumbs record the path the user is taking.
Broken Data and Advanced Algorithms
While assigning breadcrumbs, GPS units may have dropped signals or problems receiving the satellite transmissions. When this occurs, breaks in the track and breadcrumb data occur. Using an advanced algorithm, a GPS unit computer's track-smoothing function calibrates the logical breadcrumb position and assigns it, regardless of dropped signal.
Smooth Tracks and Data
After the algorithm is run, the track on the screens appears to be a fluid and smooth track without the dropped positions resulting from disruptions in the signal. This feature allows for more accurate trails and tracks from the GPS unit.
Kalman Filter
When the accuracy of breadcrumbs and fixed points in the GPS unit is compromised, another track smoothing tool in an equipped unit is a Kalman filter. The Kalman filter is called a recursive filter, and estimates the linear dynamic systems from "noisy" data collection. Said simply, it helps to extrapolate breadcrumbs from dropped signals.
Outside Sources for Track Smoothing
Some GPS units do not have the function of track smoothing. When you have a need for track smoothing and you do not have this function, outside sources such as Trailguru have online track smoothing functions. Refer to the resource section for a link to the Web site.
Article Written By Eric Cedric
A former Alaskan of 20 years, Eric Cedric now resides in California. He's published in "Outside" and "Backpacker" and has written a book on life in small-town Alaska, "North by Southeast." Cedric was a professional mountain guide and backcountry expedition leader for 18 years. He worked in Russia, Iceland, Greece, Turkey and Belize. Cedric attended Syracuse University and is a private pilot.
