Capability
Boulder · New Mexico · United Kingdom
Capabilities / Alt PNT
Alt PNT
Positioning, navigation and timing that survives GPS denial, degradation and spoofing.
The problem
Why this is hard
Satellite navigation is a faint signal arriving from a long way away. A transmitter close to a receiver can drown it out, and a signal can be replayed or forged so that a receiver reports a position it is not at. Neither failure announces itself. A platform that has been given a false fix behaves exactly like a platform that is working, right up to the moment it acts on the wrong answer. Anything that has to keep operating through that — an aircraft, a vessel, a ground vehicle, a fixed installation — needs a source of position and time it does not have to receive.
The answer
What the sensor does
What satellite navigation really distributes is time. Hold time locally, to atomic precision, and much of what the constellation was doing can be done on board: a receiver can weigh a plausible signal against an implausible one, and navigation can continue from inertial and magnetic references while the sky is unusable. Doing that has historically meant a rack. Doing it on a chip is what makes it available to the platforms that need it most.
Applications
Example applications
Spoofing detection
An independent reference on board makes a forged fix detectable, because the forged position disagrees with a clock the attacker cannot reach.
Jam resistance
When the received signal is buried, navigation continues from references that are carried rather than broadcast.
Assured navigation
Position and time that degrade gradually instead of failing at once, so an operation continues rather than aborts.