M-Code, the Defense Department’s next generation military position, navigation and timing (PNT) capability, could be fielded by the end of the decade, if not sooner, according to a key Air Force officer.

Though Air Force Space Command (AFSPC) chief Gen. John Hyten said on Tuesday DoD’s current PNT system, the Global Positioning System (GPS), would be around as long as he’s alive, Hyten said cheap and accessible jamming capabilities has DoD thinking about its next-generation system. Hyten said M-Code, presently in development, undergoing technology maturation and risk reduction, has anti-jam and anti-spoof capabilities.

Artist's illustration of the GPS IIF satellite. Photo: Boeing.
Artist’s illustration of the GPS IIF satellite. Photo: Boeing.

The M-Code signal is much improved over the present P(Y)-code precision military signal, offering additional signal power and a new signal structure. Federal laws enacted in 2011 require the use of M-Code-capable user equipment by the time the 24th M-Code-capable GPS satellite was declared operational. An Army statement from January estimated this to take place in five-to-seven years. Another 2011 law, unless waived by the defense secretary, bars procurement funds from being used after fiscal year 2017 to purchase GPS receivers not capable of receiving M-Code.

Hyten, at a Defense Writers Group breakfast in Washington, said DoD’s biggest challenge moving forward will be integrating user equipment that can take advantage of M-Code capabilities. He said DoD has in the range of “hundreds of millions” of receivers that will need to be retrofitted.

DoD wants to create PNT solutions independent of satellite connectivity, hence Hyten’s concerns about jamming. Defense Secretary Ashton Carter said last week in a major speech in Silicon Valley that DoD will advance microelectromechnical system technology for small inertial navigation units to find alternatives to GPS for military PNT.

This microelectromechanical system technology, Carter said, will feature small, accurate accelerometers and precision clocks on a chip. He said this technology is already available in smartphones and DoD will push it to be far more precise.

Carter also said DoD will push the PNT technology envelope by harnessing prize-winning physics research that uses lasers to cool atoms. Carter said this could create a “GPS of things,” where objects, including military systems, keep track of their position, orientation and time without the need for updates from satellites from the moment they are created.

Hyten also sees chip-scale atomic clocks as a revolutionary technology that could serve as the foundation for future PNT. Chip-scale atomic clocks are the heart of a minuscule atomic clock, with inner workings the size of a grain of rice that consume less than 75 thousandths of a watt.

Chip-scale atomic clocks are also stable to one part in 10 billion, equivalent to gaining or losing just one second every 300 years, according to the National Institute of Standards and Technology (NIST). Hyten said combining the chip-scale atomic clock with signals from two PNT constellations, like the United States’ GPS and Europe’s Galileo, and what he called a “truth chip,” would generate even more accurate PNT. Hyten said the “truth chip” determines if one of the signals providing PNT measurements has been spoofed.

“I think (the chip-scale atomic clock) is going to be the fundamental game changer from a military perspective,” Hyten said, though he added he believes GPS will remain the “gold standard.”