Short answers, pulled from the story.
Stick charts are physical models of ocean swells and island positions crafted from coconut fronds and shells. Polynesian navigators used these charts to traverse vast stretches of the Pacific Ocean without metal instruments or written records by relying on knowledge of wave refraction, seabird flight patterns, and star positions.
The compass originated in China during the Han dynasty around 206 BC. It became the cornerstone of maritime navigation when adopted by Song dynasty sailors in the 11th century and arrived in Western Europe and the Islamic world around 1190.
John Harrison solved the longitude problem by developing a marine chronometer that could withstand ocean conditions and maintain accuracy over long voyages. His H5 chronometer completed in 1772 allowed navigators to compare local time with Greenwich Mean Time to calculate their exact east-west position.
A marine sextant is an optical instrument used to measure the angle between a celestial body and the horizon to determine distance from that body's subpoint on Earth. This process requires a nautical almanac and a source of time to compute the subpoint and create a circular line of position.
The Global Positioning System was officially named NAVSTAR GPS and the first experimental satellite was launched in 1978. This system uses a constellation of over 100 satellites in medium Earth orbit to transmit time signals that allow receivers to determine their location within a few meters.
Inertial navigation systems calculate position based on motion sensors rather than external signals by using accelerometers and gyroscopes to measure acceleration and rotation. These systems determine latitude and longitude without needing outside information, making them immune to jamming or adverse weather.