Citation

Reust TJ. Collision 2010; 5(2): 86-88.

Copyright

(Copyright © 2010, Collision Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Motor vehicles increasingly are being equipped with global positioning system (GPS) navigation units. These GPS units often record and store information that can be potentially useful in accident investigation. This article presents a preliminary look at GPS data logging for accident investigation purposes. Testing was conducted to evaluate the time, speed and coordinate accuracy of GPS data logging. The number of logged files held in memory was also investigated. Five different models of GPS units were installed in a single instrumented vehicle that was then run through different maneuvers, including rapid acceleration, rapid deceleration, modest acceleration, constant speed, changes in heading angle and stop-and-go events. The findings showed that the GPS units offered good agreement with the calibrated speed from the instrumented vehicles. The number of log files held in memory differed by model, but ranged between 35 and 90. To review the accuracy and repeatability of a given GPS coordinate, a vehicle was brought to a stop and then the position of the GPS unit was marked on the highway. The GPS unit was downloaded to retrieve the engine coordinates. A handheld GPS unit was then used to locate the coordinates. The same process was repeated three times with a wait time of approximately two hours between tests. Results showed that the positions were close, but showed progressive error over time, probably due to the GPS position drift as the satellites move in orbit. These preliminary findings indicate that the GPS shows promise as an accident evaluation tool.