Positioning, navigation, and timing (PNT) solutions may appear at first glance to be relatively new technological concepts given the recent advent of the Digital Age, but PNT has been around for centuries.
PNT has been crucial for the world’s militaries since the days of Greek galleys and Roman legions. Commanders needed to know when and where to position their fleets and armies and relied upon analog tools such as sundials, sextants, compasses, and chronometers to process celestial and magnetic information that would help determine their time and place on the earth’s surface.
In the 20th century, many of these mechanical PNT tools were replaced by electronic ones. In the late 1950s, the launch of Sputnik was the dawn of satellite-based navigation. In the Sputnik era, scientists tracked the satellite with shifts in its radio signal known as the “Doppler Effect.” The U.S. Navy then developed satellite navigation experiments in the mid-1960s to track U.S. submarines carrying nuclear weapons. With six satellites orbiting Earth’s poles, submarines were able to observe the satellite changes in Doppler and pinpoint the submarine’s location within a matter of minutes.
In the early 1970s, the Department of Defense (DoD) built on the research of the Navy scientists with a goal toward creating a robust, stable satellite navigation system. The DoD elected to use satellites to support their navigation system, and the launch of the DoD’s first Navigation System with Timing and Ranging (NAVSTAR) satellite in 1978 kicked off the project. Within 15 years, the DoD’s 24 satellite systems became fully operational. This system created by the military is known in the U.S. as the Global Positioning System (GPS).
As other satellite-based navigation systems have come online, the term Global Navigation Satellite System (GNSS) has become the generic term to describe satellite-based navigation systems. Today, GPS remains the predominant navigational solution for both military and commercial applications. Offering a positional accuracy within one meter and timing better than 100 nanoseconds, GPS is the ubiquitous add-on to virtually every consumer mobile device and commercial navigational system on the market. Inexpensive, accurate GPS applications now help everything from motorists to military units get to where they need to go.
However, for every technological advance there are threats to derail it.
KVH’s newest eBook, Position Navigation & Timing Assurance: Meeting the Growing Threat of GPS/GNSS Disruption, takes a look at the technology that helps deliver PNT in the modern world, the natural and technological threats to its effectiveness, and the means to mitigate those threats. Download your free copy today.