• The compass, 12th century
  • sextant 1757 – It made maps out of stars – determine the angle between an astronomical object and the horizon for the purposes of celestial navigation. The determination of this angle, the altitude, is known as sighting (or shooting) the object, or taking a sight. The angle, and the time when it was measured, can be used to calculate a position line on a nautical or aeronautical chart.
  • GPS