Triggers for Apple sensor-data uploads

Identify what triggers the sensor-data uploads made by locationd and geod, including uploads of Wi-Fi and cellular observations, GPS fixes, pressure, temperature, compass, pedometer and motion data.

Background

The measurements show that iOS collects sensor data and transmits it in batches, often with substantial delays. The paper observes different upload types and timing patterns but does not establish the conditions that cause each upload to occur. Determining these triggers is necessary for understanding when sensor and location histories are transmitted to Apple.

References

We have not established what triggers each upload.

— Decoding What iOS Location Services Send to Apple: An LLM Is an Unreliable Analyst but a Useful Toolmaker  (2610.21597 - Leith, 15 Oct 2026) in Section 3.3, “Apple’s ‘Harvesting’ Of Phone Sensor Data”

We did not test those settings (Routing and Traffic, Improve Location Accuracy and Significant Locations), so we do not know whether they stop the uploads and requests that we observe, nor whether the telemetry and the Wi-Fi quality lookups have a control at all.

— Decoding What iOS Location Services Send to Apple: An LLM Is an Unreliable Analyst but a Useful Toolmaker  (2610.21597 - Leith, 15 Oct 2026) in Section 4, item 7, “Apple Privacy Policy”