Marine Decca Systems were hyperbolic radio navigation systems used for coastal and short-range maritime navigation. They provided accurate position fixes by measuring phase differences between continuous wave signals from shore-based stations. Primarily used from the 1940s to the 1990s, they were eventually superseded by GPS technology.

The Marine Decca Navigation System is a hyperbolic radio navigation system that operates in the frequency range of 70–130 kHz. Key specifications include:

Size: Ground stations consist of large antennas, typically spanning 100–300 meters in height.

Grade: High-precision navigation system with accuracy ranging from 50 to 500 meters, depending on distance from the transmitter.

Viscosity: Not applicable (electronic system).

Buoyancy: Not applicable (land-based transmitters and shipboard receivers).

Material: Antennas are typically made of steel or aluminum; shipboard receivers use durable, corrosion-resistant materials.

Operating Range: Up to 400 nautical miles from the transmitter.

Power Output: Transmitters range from 100 W to 2 kW.

Frequency Stability: High stability, with phase-locked loops ensuring precise signal synchronization.