Why GPS and Radar Might Disappear
Modern carriers rely heavily on satellite‑based GPS and ship‑mounted radar for precise positioning, threat detection, and coordination. In a high‑intensity conflict, adversaries could employ anti‑satellite missiles or electronic‑warfare techniques that knock out these systems within seconds, leaving the ship without its primary navigation aids.
Traditional Navigation Tools Still Viable
Even in a fully electronic blackout, centuries‑old methods remain reliable because they depend on natural phenomena rather than power‑intensive electronics.
- Celestial Navigation: Using a sextant to measure angles between celestial bodies (sun, stars, moon) and the horizon, then calculating latitude and longitude with almanac tables.
- Magnetic Compass: Provides a constant heading reference unaffected by electronic interference.
- Dead Reckoning: Tracks course, speed, and time to estimate position from a known starting point.
- Radio Beacons & LORAN: Low‑frequency terrestrial signals that can be used when satellite links are down.
The 2022 USS Essex Exercise
In 2022 the amphibious assault ship USS Essex sailed 1,800 nautical miles from Oahu to San Diego using only paper charts, a compass, a sextant, and handwritten calculations. The crew was prohibited from using any electrically powered navigation aids. The ship stayed within one nautical mile of its intended track for most of the five‑day voyage, proving that manual navigation can meet modern operational standards.
Reinstating Celestial Navigation Training
Recognizing the vulnerability of satellite‑dependent systems, the U.S. Navy reinstated formal celestial navigation training in 2016. Sailors now practice:
- Reading and plotting sextant sightings.
- Using the STELLA (System to Evaluate Latitude and Longitude Astrometrically) software suite as a supplemental aid.
- Integrating manual fixes into the ship’s integrated navigation system for redundancy.
Future Preparedness
To ensure resilience, carriers are adopting a layered navigation approach:
- Primary reliance on GPS and radar under normal conditions.
- Secondary reliance on inertial navigation systems (INS) that continue to track position without external signals.
- Tertiary fallback to traditional methods—celestial, compass, dead reckoning—maintained through regular drills.
By keeping these time‑tested techniques in the skill set of every navigator, the U.S. Navy can maintain operational effectiveness even when the “lights go out.”