How FastTrack Gets Pro-Grade Timing Accuracy From Your iPhone
FastTrack's 0-60 times land within ±0.02 seconds — close enough to dedicated $200+ hardware that the difference comes down to GPS antenna quality, not software. The engine fuses Doppler GPS with the iPhone's 100 Hz accelerometer using the same class of sensor-fusion math NASA trusted to fly Apollo 11 to the Moon.
Methodology
- ±0.02s 0-60 accuracy — within the standard Dragy's ±0.03s window and within hundredths of Dragy Pro and RaceBox under normal conditions
- ~30ms launch detect latency — the 100Hz accelerometer registers acceleration onset roughly 3× faster than GPS-only launch detection (~100ms)
- 100Hz accelerometer sample rate — paired with 1Hz GPS Doppler velocity through a Kalman-style estimator that blends both signals continuously
- 3–5× tighter than GPS-only — the gap that remains is hardware: dedicated devices have purpose-tuned external antennas; a phone sits inside the cabin
What Sensor Fusion Actually Does
GPS knows your absolute speed but only updates once per second and carries noise. The accelerometer updates 100 times per second and is very responsive, but drifts over time. The fusion algorithm blends them continuously so the result is both fast and stable — the same approach used in Apollo guidance computers, SpaceX landing systems, Tesla Autopilot, and self-driving research vehicles.
How Close to Dragy and RaceBox?
For 0-60 times, FastTrack is now within a few hundredths of Dragy and RaceBox under normal conditions. The math and algorithm class are effectively the same. The remaining gap is almost entirely hardware: a dedicated device has a purpose-tuned external antenna with clear sky view, while a phone sits inside the cabin. For most enthusiasts, FastTrack is the accuracy they need without spending $150 to $500 on extra hardware.
FastTrack vs Dragy | FastTrack vs RaceBox | Timing Accuracy Deep Dive