GPS Sampling Rate Trade-offs and Battery Optimization

Sampling Rate Impact

Higher GPS sampling rate means more points and better matching accuracy. 1 Hz (one point per second) captures turns and lane changes well. 0.1 Hz (one point per 10 seconds) may miss turns entirely, making matching ambiguous.

But higher rates drain battery faster and increase data volume. A 1 Hz trace generates 3600 points per hour. At 10 bytes per point, that is 36 KB per hour per device. Multiply by millions of devices.

Minimum Viable Rate

Matching accuracy degrades gradually as sampling rate decreases. At 1 Hz, accuracy is near perfect. At 0.5 Hz, still good. At 0.1 Hz, significant degradation at complex intersections. At 0.05 Hz (one per 20 seconds), matching becomes unreliable for urban driving.

Minimum rate depends on driving context. Highway: lower rate acceptable, few turns. Urban: higher rate needed, frequent turns. Adaptive sampling: increase rate when speed changes suggest turns, decrease on straight roads.

Battery Optimization

GPS duty cycling: Turn GPS on periodically rather than continuously. 1 second on, 4 seconds off gives 0.2 Hz effective rate with 80% power savings versus continuous.

Motion-based activation: Use accelerometer to detect movement. GPS only when moving. Parked vehicles do not need positioning.

Cell tower fallback: Use cell tower positioning for coarse updates when GPS is off. Less accurate but sufficient for detecting major location changes.