By David Kramer
Cold-atom interferometry, microelectromechanical systems, signals of opportunity, and atomic clocks are some of the technologies the defense agency is pursuing to provide precise navigation when GPS is unavailable.
[big_button url=”http://scitation.aip.org/content/aip/magazine/physicstoday/article/67/10/10.1063/PT.3.2543″]Read More[/big_button]
