Although initially, at the time of installation of GPS tracking devices in a vehicle, the odometer on the GPS control platform is synchronized with the actual value visually read on the vehicle; it should be noted that over time there will always be a variation between the mileage displayed on the vehicle´s odometer and the mileage displayed on the platform. This will happen with any GPS solution, as we are essentially talking about two different measurement systems that inherently have error elements of a totally different nature.
Assuming that we will always have differences, then the following question comes to mind:
Which device is more accurate: the odometer or the GPS?
Understanding that these are two different measurement systems, it cannot be assured that one is more accurate than the other. Circumstantially, one will have more error than the other depending on how it is affected by external agents, as we will mention below.
The vehicle's odometer is a direct measuring instrument that is mainly affected by variations or wear and tear in its support elements: tires, rims, transmission, bearing elements. This means that the simple fact that the tires wear-out or are replaced by others different from brand and size specified by the manufacturer, will lead to odometer readings that do not conform to reality. There will always be a difference between the distance actually traveled by a vehicle and the odometer reading, especially in vehicles that are not late model.
GPS tracking systems, on the other hand, use satellites to determine the vehicle's geolocation at all times with incredible precision and accuracy, obtaining a reading based on distances traveled from differences in location between measurement points. This measurement is very accurate under normal weather and topography conditions. However, they may also be affected by the way the measurement is applied. Typically, signal loss due to physical obstruction and unconsidered micro-displacements between location measurements are usually the most important factors affecting accuracy.
Technically, studies performed for both measurement systems recognize an error that can range from 2% to 8%, resulting in an average of 5%-point difference. In some cases, the difference might have a cumulative effect and generate more significant differences between the two systems.
Because GPS platforms for fleet management allow to easily enlist the odometers of many vehicles simultaneously, verify their routes, and define alerts; we recommend considering it as a highly acceptable and reliable reference for the purposes of monitoring your vehicles. The telematics industry has shown that the difference in measurements over a typical time or travel range is not significant. And telematics services keep growing in reach and popularity!
If, however, you deem necessary to maintain similar measurements, we recommend that you consult our NAVSAT Customer Service Department to guide you through the calibration process. This simple process can be done remotely, in coordination with NAVSAT Technical Support personnel.
GPS measurement systems also allow you to calculate with very good accuracy the speed, idle times, and many other variables of your mobile assets; generating the possibility of being notified in case any of your units exceeds the parameters defined as excesses or acceptable thresholds by the administration.
Undoubtedly, GPS mobile resource control technology is an invaluable tool for the operational control of vehicle fleets, as well as for the better management of mobile resources in your company.