SCHRIEVER AIR FORCE BASE, Colo. --
Many people around the world use Global Positioning System receivers and applications in their vehicles and cell phones to guide them to their destinations. But few people know much about the GPS signal itself.
Air Force Space Command Airmen of the 2nd Space Operations Squadron at Schriever Air Force Base, Colo., are the lead unit for GPS. Together with the Air Force Reserve Command's 19th Space Operations Squadron, they are the sole global providers of the GPS signal through their command and control operations of the GPS constellation.
Funded by the American people, on any given day, more than 3.5 billion people around the world have access to GPS signals at no charge. With this access, civilians are finding more ways to apply GPS technology in their everyday lives. Today, GPS is used to increase productivity throughout global economies. The signal guides tractors and planting operations in agriculture and has revolutionized global tracking of commercial goods. The signal allows faster emergency and disaster response efforts and has made personal fitness workouts more efficient.
The GPS signal allows many other capabilities beyond navigation. The GPS constellation uses an atomic clock accurate within one billionth of a second. The precision of this clock enables banks, the stock market, and even traffic lights to perform with complete precision. In fact, every ATM and debit card transaction relies on the GPS timing signal. This timing capability allows military units around the world to conduct coordinated missions at the exact same time.
The navigation signal is equally critical to defense department innovations. The JDAM is a guidance tail kit that converts existing unguided free-fall bombs into accurate, adverse weather smart munitions. The GPS guidance control unit then navigates the weapon system autonomously to the designated target.
Similar to the guidance kit for munitions, GPS-guided 'smart pallets' allow air-dropped supplies to land at specified locations, improving humanitarian aid delivery or troop resupply, day or night, under any conditions.
"This program is unique as it started out for military, and military only, and then it was opened up to civilian users," said Capt. Aaron Blain, 2nd SOPS chief of navigation. "Many people don't actually understand how GPS works on a regular basis; they think they are actually contacting the satellite directly and this isn't true. Essentially, you are just receiving a signal."
When someone activates a GPS receiver or enters an address into a GPS device, the signal they are receiving triangulates where they are on Earth and where they want to go. Software within the device uses that signal to get travelers from point A to point B.
"Some of the things we do behind the scenes is try to optimize the signal and make it as accurate as possible," said Blain. "Satellites have what we call atomic frequency standards, which is essentially a clock, a very accurate clock. Each satellite has its own personality; we make them more accurate for everyone in the world."
The system's timing synchronization supports major communication networks, financial markets, and power grids. In fact, some wireless services cannot operate without GPS.
"We have a constellation of 39 satellites, so every day is a different type of scenario, and we have contingency plans for any situation," said Senior Airmen Trey Barnes, 2nd SOPS space systems operator. "Some of the situations we contend with are collision avoidance with other satellite vehicles, orbital debris, or space weather. Space is a rough environment and it's important to stay calm."
As the Defense Department's largest satellite constellation, GPS has increasingly exceeded accuracy standards. Today's commercially-available GPS devices are accurate to within one meter (about three feet). The U.S. military's GPS capabilities are accurate to within half a meter.
In 2011, the Air Force GPS program was recognized for its "measurable benefit to humanity." The International Astronautical Federation celebrated their 60th anniversary with a one-time award for the single space event with the greatest contribution to humanity presented at the 62nd International Astronautical Congress in Cape Town, South Africa. Nominated by the American Institute for Aeronautics and Astronautics, the GPS program was awarded for the, "uniqueness of the GPS program and the exemplary role it has played in building international collaboration for the benefit of humanity," according to the IAF website.
"The squadron has been remarkably successful," said Blain. "The GPS program has been recognized as the greatest contribution to humanity. We're humbled that we can help people every day."
(This article is part of the 30 Days with Space and Cyber Airmen that tells the story of Airmen and mission partners conducting critical space and cyber missions during the month of September.)