How could it tell coordinates in either space or time? non-military-grade GPS is spoofable (not really easy yet, but easier by the day) and GPS signal is rarely

How could it tell coordinates in either space or time? non-military-grade GPS is spoofable (not really easy yet, but easier by the day) and GPS signal is rarely available inside a building (and sometimes just under an awning or cloudy days, or near skyscrapers - GPS in NYC is horrible; mobile phone GPS are as reliable as they are because they take cell towers and wifi into account). The important point is " making it harder " - but how hard is hard enough depends on the party in question, and for many important ones, the simple answer is "not hard enough".