WASHINGTON — As intentional GPS interference becomes more commonplace, a California startup is proposing an unconventional solution: doubling down on the system’s newest signal, known as L5.
The L5 is the Global Positioning System’s newest civilian signal, designed to operate in a frequency band reserved for aviation safety services, complementing the existing L1 and L2 frequencies.
The startup oneNav developed an “L5 direct” receiver for commercial use in smartphones and internet-of-things (IoT) devices. The receiver directly acquires L5-band signals without first locking onto the older L1 signals, making it resistant to jamming attempts, said Steve Poizner, the company’s chief executive.
The company is marketing the receiver to the U.S. military, leveraging the results of tests conducted in April in high-jamming areas like Israel and along the Poland-Ukraine border, Poizner told SpaceNews.
oneNav researchers compared the performance of L1 and L5 signals in areas with frequent GPS interference, he said. “While researchers observed widespread jamming of L1 signals across the region, from Finland to Turkey, signals that directly acquired the L5 band proved immune to attempts at interference.”
The military could use L5 receivers in drones, precision-guided weapons, mobile radios, and troop trackers, he said.
The L5 band is broadcast by a portion of the GPS constellation and by other global navigation satellite systems such as Europe’s Galileo, China’s BeiDou and Japan’s QZSS.
GPS modernization planned
Despite its potential, the GPS L5 signal is not yet widely used as it’s only being broadcast by 17 out of 31 GPS satellites in orbit. Full operational capability with 24 satellites broadcasting L5 is not expected until around 2027. The L5 signal is part of the GPS modernization plan to be implemented gradually as the constellation is renewed.
The L5 signal is still considered “pre-operational” and not yet fully certified for critical applications. Most existing GPS receivers are not equipped to use L5 signals. Another bottleneck is the implementation of GPS’ next-generation Operational Control System, known as OCX. The new ground system is crucial for fully leveraging L5 capabilities, but is years behind schedule.
These factors collectively contribute to the slow adoption of the L5 signal, despite its promised advantages in terms of accuracy and interference resistance, Poizner said.
oneNav’s approach caught the attention of In-Q-Tel, the U.S. intelligence community’s venture capital arm, which participated in oneNav’s $21 million Series B funding round in May 2021.
The Pentagon has undertaken several initiatives to reduce its dependence on GPS and address vulnerabilities of GPS signals. The U.S. Space Force, for example, is looking to harness commercial innovations in PNT (positioning, navigation and timing) technologies.
“It’s smart government policy to be investing in a wide variety of ways to produce precise time and position in real time,” Poizner said. “However, GPS/GNSS is the only global solution using existing infrastructure available today for both civilians and warfighters.”
