The USAF Test Pilot School at Edwards Air Force Base, Calif., is known for providing high quality resources for greater aerospace testing.

This was recently demonstrated through their partnership with Los Angeles based “StarNav” to test a unique GPS system.

Flown on a special T-38C from Holloman Air Force Base, the system aims to provide more accurate navigation information to older aircraft using existing onboard antennas. TPS proudly named this project “Have 5tarboy”.

“It’s an interesting project and name,” Capt. Nathan Raquet, Project Lead, USAF TPS explained. “We changed the ‘S’ to a ‘5’ in our project ‘5tarboy’ because we are testing the L5 GPS signal. The project is testing a L5 and GPS Galileo E5A receiver through existing hardware on the aircraft on this case, a T-38C.”

Traditional GPS signals are split into L1, L2, and L5 signals. “5tarboy” would further utilize the GPS L5 signal reception through existing onboard antennas that would be more accurate for navigation guidance on aircraft.

“We are seeing can this implementation of the receiver work and then see how can L5 and Galileo E5A be used to improve the navigation systems already on the aircraft,” Raquet explained.
L1 and L2 signals have been around for years but the newer L5 GPS signal is not always utilized by older military aircraft, sometimes because of outdated GPS antennas. With the help of StarNav LLC, a LA based company that implements leading edge technologies, the implication of a successful test of “5tarboy” would be a system that provides accurate navigation information to older aircraft using the existing onboard antennas.

“GPS L5 is the newest signal that is being deployed on GPS satellites,” Joshua Morales, CEO of StarNav explained. “What StarNav has been working on is a piece of equipment that allows jets to be able to use those signals and it allows the team to accomplish this without equipping the aircraft with new hardware.”

Using a test kit and a mobile GPS space station, the “5tarboy” team makes sure the navigational test goes as smooth as possible.

“With the test kit, we do a bit of regression testing so we make sure the capabilities of the aircraft are still unaffected by our system,” Capt. Steve O’Briant, Project Pilot, USAF TPS said.
“The TPS students painted a bus that looks like the X-62 VISTA,” Raquet explained. “We are using it for our test as a GPS space station. So, we are recording GPS on the T-38C and also the space station and we use what is called differential GPS processing to get a more accurate position solution for the test.”

The 412th Test Wing Guidance and Navigation Technical Adequacy Office desired to have a solution that can produce accurate position information while undergoing this project that would benefit the warfighter, the Edwards test mission and the Department of Defense as a whole.

“The more frequencies you have, you can correct for atmospheric errors and it also gives you more redundancy in the electromagnetic spectrum by having more ways of getting information,” Raquet explained.  “If we don’t do this test, we don’t have the answers to if this implementation is realistic and we won’t have this asset available to the test community.”

With a successful test from the “5tarboy” team, more accurate navigation information using the L5 GPS signal is slowly becoming possible with aircraft in the United States Air Force.

“We have predictions that we are reviewing for validation, but we flew 7 sorties and got a ton of data during this project,” Raquet said. “I worked with the USAF TPS before, so I am very proud to be working on this Test Management Project with them again.”