While GPS accuracy for location data is generally well known, data for velocity or speed is not as well understood. Speed data is often relied upon as important evidence when a traffic violation or an accident occurs.

This paper examines the accuracy of three key parameters of Garmin GPS data integrated with the March Networks™ mobile video surveillance system; position, speed and latency. It also explains how this data is synchronized with video, and draws conclusions on the use of the data as evidence. Information is based primarily on four sources listed in the References section at the end of this document.