The Science Behind Dead Reckoning with Atomic Clocks

Dead reckoning requires two key components: precise timing and accurate velocity measurements. Modern aircraft are equipped with sophisticated sensors like accelerometers and gyroscopes, which measure changes in speed and orientation. When combined with the nanosecond-level accuracy of atomic clocks, these sensors enable pilots to determine their position relative to their last known coordinates.
 

For instance, suppose an airplane loses its GPS signal due to jamming. With a CSAC onboard, the plane’s avionics system would use the clock’s unwavering timekeeping to synchronize sensor data and compute its trajectory. While not as precise as GPS over long durations, this approach provides sufficient accuracy to guide the aircraft safely until the signal is restored or another navigational aid becomes available.