Hardware PLL & Clock Steering™

The Spatial-Temporal Misalignment Issue

In telemetry drive-testing, mapping cellular data requires absolute synchronicity between cellular signal strength packets and GPS coordinates. However, GPS updates (typically arriving on a 1Hz clock) and cellular modem updates (arriving asynchronously) run on completely separate system clocks.

When recording at high speeds, this timing offset results in "spatial jitter". At 120 km/h, a tiny 500ms desync translates to a spatial shift of 17 meters, misaligning cellular readings with their actual location. Furthermore, logging data asynchronously causes "coordinate clumping"—where multiple distinct cellular packets are tied to the exact same coordinate because a new GPS fix has not arrived.

Hardware-Locked Clock Steering

CellScout implements a software-based Phase-Locked Loop (PLL) and Clock Steering algorithm to eliminate spatial drift. Upon detecting dynamic mobility, the logging clock suspends fixed temporal updates and steers its query cycles to align directly with physical GPS hardware coordinate arrivals.

If the cellular logging thread is scheduled to write a packet but the GPS hardware is lagging, the logging loop goes to sleep utilizing a precise thread-synchronized wait lock. The exact moment the GPS hardware registers a fresh coordinate, the thread wakes and executes an atomic log snapshot. This clock synchronization completely eliminates spatial jitter and coordinate clumping, producing perfectly linear, mathematically precise drive test logs.