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An LAPD helicopter claimed to have ID'ed protesters from above and threatened to "come to your house"
(www.motherjones.com)
This is a most excellent place for technology news and articles.
I don't think their gyroscopes are good enough for that level of inertial navigation. You could just fling it around tossing it up in the air and down again, that would totally mess with its navigation.
The far greater threat is that you just have the phone taken off you. For that reason alone you should use a burner, but I don't think you should be worried that they can track you based on gyroscope history.