Refine Vehicle 0-100 Timer App

I already have a working 0-100km/h timer that runs on both iOS and Android. The UI is finished and the app is in a private test build; I now need a developer who can make its results as precise as possible... (Budget: $250 - $750 AUD, Jobs: Android, Android App Development, App Development, GPS, iOS Development, iPhone, Mobile App Development, Mobile Development, Software Architecture, Software Development)