A method of determining the distance traveled during an event by a mobile GPS receiver. The event comprises epochs. The method comprises receiving pseudorange data comprised of one of pseudorange differences or range rates. Each pseudorange difference, in turn, comprises a difference between a first pseudorange and a second pseudorange. The first pseudorange comprises the pseudorange between the receiver and a GPS satellite at a first epoch. The second pseudorange comprises the pseudorange between the receiver and the GPS satellite at a second epoch. The range rates comprise a range rate measurement taken by the receiver of the GPS satellite from the first epoch to the second epoch. Line-of-sight data comprised of at least one normalized vector between the receiver and the GPS satellite is then determined. Based on the pseudorange and line-of-sight data, incremental distance data is then determined. A sum over the event of the incremental distance data is then determined.