What blocks a GPS tracker from working?

Physical things that block GPS

• Roofs and buildings. GPS rarely works well indoors.
• Tunnels and underground car parks. No sky, no fix.
• Tall buildings. They block and reflect signals, which causes errors as well as gaps.
• Metal. A tracker inside a metal box, container or van with a metal load has a much harder time.
• Dense tree cover and heavy rain weaken signals, though usually not completely.

Things on the phone that stop tracking

• Battery optimisation closing the app in the background — the most common cause.
• Location permission set to “only while using the app”.
• Location turned off or airplane mode.
• No mobile data — the phone may know where it is but can’t send it (see GPS without signal).

GPS jammers are illegal

GPS jammers block signals deliberately. Using one in the UK is a criminal offence under section 68 of the Wireless Telegraphy Act 2006, punishable by up to two years in prison and an unlimited fine. Jammers are associated with vehicle theft, which is one reason some trackers report when their signal suddenly drops.

How to get a reliable GPS signal

1. Keep the phone or tracker with a view of the sky where possible (a dashboard mount, not a glovebox).
2. Exclude the tracking app from battery optimisation.
3. Grant location permission for tracking while working.
4. Use an app that stores positions offline and sends them when signal returns.

Common questions