Due to the risk of cyber attacks targeting ships' satellite navigation, National Naval Services are delving through history and develop back-up systems with roots in World War Two radio technology.
Ships use GPS (Global Positioning System) and other similar devices that rely on sending and receiving satellite signals, which many experts say are vulnerable to jamming by hackers.
About 90 percent of world trade is transported by sea and the stakes are high in increasingly crowded shipping lanes. Unlike aircraft, ships lack a backup navigation system and if their GPS ceases to function, they risk running aground or colliding with other vessels.
South Korea is developing an alternative system using an earth-based navigation technology known as eLoran, while the United States is planning to follow suit. Britain and Russia have also explored adopting versions of the technology, which works on radio signals.