Data update frequency
- GPS trackers typically report data at intervals (e.g., every 10s, 30s, or 1 minute). If the vehicle accelerates or decelerates during this interval, the reported speed may not reflect the real-time change.
GPS signal quality
- In areas like tunnels, urban canyons, or underground parking, GPS signals can be weak or unstable, causing location drift and affecting speed calculation.
Different speed calculation methods
- GPS trackers calculate speed based on the distance between two location points divided by the time interval, which may be affected by signal noise.
- Vehicle dashboards display speed measured directly from the wheel speed sensors, which is more real-time but can be influenced by tire wear or pressure.
Delays and filtering algorithms
- To save data usage, the trackers may merge or filter out data when the vehicle is stationary or moving slowly, causing the reported speed to appear lower or discontinuous.
Typical deviation range (for reference):
- Normal deviation: ±2–5 km/h
- Poor GPS signal: May result in larger deviations or abnormal speed spikes