DARPA developing GPS backup and beyond Technologies for GPS denied and degraded environments

The GPS system provides critical positioning capabilities to military, civil, and commercial users around the world. The Global Positioning System (GPS), is a global navigation satellite system (GNSS) that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. GPS has become ubiquitous technology that provides real-time positioning, navigation and timing (PNT) data in cars, boats, planes, trains, smartphones and wristwatches, and has enabled advances as wide-ranging as driverless cars, precision munitions, and automated supply chain management.