# Blog

The Power of STL for Assured PNT

For military personnel, keeping sight of the enemy can mean the difference between life and death. Military leaders frequently emphasize their need for reliable and accurate positioning, navigation and timing (PNT) systems. Accurate PNT is critical for their communications, sensors, network systems, and search and rescue missions.

Today, many systems rely on mature global navigation satellite systems (GNSS) such as GPS, GLOSNASS and Galileo for positioning and navigation, as well as for timing. But GPS technology is decades old, with weak signals that are vulnerable to interference. To protect military personnel on land, sea and in the air, the military is beginning to augment GPS with newer technologies to achieve resilient PNT, or assured PNT.

Value and Vulnerabilities of GPS

Developed by the U.S. military, GPS relies on satellites with atomic clocks to transmit signals at precise intervals. Using receivers on earth, refined calculations and triangulation, one can determine an object’s exact location at a precise time. For example, GPS helps the military in search and rescue missions by identifying the location of a pilot, soldier or sailor in distress, or synchronizing critical communication infrastructure. Applications for GPS technology are practically endless and its use today is ubiquitous.

However, GPS is being used in ways never envisioned 30 years ago – exposing shortcomings for today’s applications. GPS signals are fragile, with limited ability to penetrate structures, dense forests or rugged terrain. Enemies can jam or spoof signals more easily than ever. Although these vulnerabilities may not significantly impact consumers, they can have life or death implications for military personnel, who simply cannot afford to have missing or inaccurate signals.

Adding Signals of Opportunity for Assured PNT

One way to shore up GPS technology is to augment with additional PNT sources. Combining GPS with complementary technologies through signals of opportunity such as Satellite Time and Location (STL) or eLoran, offsets the shortcomings of each. Signals of opportunity can provide::

  • Stronger signals: many times stronger than GPS and other GNSS signals
  • Resiliency to interference: operating in environments where GPS cannot be reached
  • Robust security: delivering encrypted signals and a license key specific to each receiver, making it very difficult to spoof

For military personnel in combat situations – or facing search and rescue emergencies behind enemy lines – lost or spoofed signals are extremely dangerous. Every wasted second or distance places personnel further into harm’s way.

Next Best Assured PNT Technology? A Tech Combination

The best way to overcome the deficiencies of one technology is to augment it through other technologies and innovations. Signals of opportunity enable military leaders to move beyond the inherent weaknesses of GPS by adding redundancy. Together, GPS and signals of opportunity deliver reliable, accurate and secure PNT when personnel need it most … saving lives and ensuring that military personnel never lose sight of their targets, even in adverse conditions.