"Researchers in Britain have gone as far as saying that GPS failures could lead to "loss of life".
One known example of an airport and planes landing there being impacted by unintentional interference has already occurred in the US, the professor said."
This NASA produced short film (3:30) describes the Global Positioning System. It is a great summary and can be used to augment the Galaxy Explorers Mission Plan on GPS.
"GPS location apps on a smartphone can be very handy when mapping a travel route or finding nearby events. But how does your smartphone know where you are? Wilton L. Virgo explains how the answer lies 12,000 miles over your head, in an orbiting satellite that keeps time to the beat of an atomic clock powered by quantum mechanics. "
Covers the increased use of GPS-tracking devices to monitor prisoners while on parole. Looks into basic monitor, plus other issues like "People and machines" and "reliability"
"The most popular corners to catch a yellow cab in Manhattan can now be pinpointed, at any hour of any day of the week, thanks to a record of 90 million actual taxi trips that have been silently tracked by the city.....the information, collected by GPS, can be used to create helpful tie-ins for customers, like a new smartphone program that lets mobile users locate the ideal nearby corner to hail a cab."