Business Insider recently spoke with Richard Easton for input on its article, How Does GPS Work?
Richard noted that while GPS costs about $1 billion a year to maintain and replenish, it produces perhaps $100 billion per year in economic benefits, quite a “bang for our buck.”
Applications for GPS continue to expand, owing largely to a decision made at the beginning–to make the system passive. GPS satellites broadcast one-way signals, like a radio station, meaning an unlimited number of users can share them without transmitting anything back to the satellite, which would saturate the system and limit its use.
![II IIA 1 GPS](http://static6.businessinsider.com/image/53c7edb5eab8ea7422a32dc0-1200-1200/ii-iia-1.jpg)
Photo via GPS.gov