A cellular phone's built-in tracking components may work even when the phone is powered down; the only sure way to stop tracking is to remove the battery. Any phone modified with an attached, self-powered tracking device can be tracked even when the phone is turned off and its battery is removed. A lack of trackability is a good thing if you don't want people tracking you but a bad thing if you're trying to locate a lost phone that has been turned off.
Power State
A cell phone's power state is relevant to whether or not the built-in tracking technology is accessible. The phone is typically trackable if it is turned on. Some phones continue to power the cellular transceiver even when the phone is powered off; these phones can be tracked over the cellular network even when turned off. The only way to make a phone fully untrackable is to remove its battery.
Feature Disabled
You can disable tracking over GPS and the cellular transceiver by enabling airplane mode on any phone that supports it. Additionally, some phones let the user individually toggle cellular and GPS functionality. If the feature is disabled, the phone can't be tracked.
GPS Tracking
GPS tracking is not necessarily malicious: it's often used through smartphone apps to track missing phones. GPS tracking works by using a network of 32 satellites to determine a device's location. GPS does not need to use an Internet connection to work correctly. The phone uses the locations of the satellites to determine where it is located. GPS is particularly useful for tracking phones in areas with poor cellular and Internet connections.