Navigators are sometimes also called 'air navigators' or 'flight navigators'. During World War II, Barksdale trained pilots, navigators, and bombardiers. Work began in earnest on a variant specifically for training military pilots, bombardiers, and navigators. These expeditions were formed by groups of navigators, merchants, adventurers and missionaries. These and similar ship types were familiar to Portuguese navigators and shipwrights. Beacons help guide navigators to their destinations. Modern smartphones act as personal GPS navigators for civilians who own them. Spherical geometry has long been used by astronomers, astrologers, and navigators. Squadron is the nursery for Fixed wing pilots, Navigators of Pakistan, and Foreign Navies. Early European navigators and missionaries described the aboriginal inhabitants of Guam. The E6-B is a circular slide rule used by pilots and navigators. Though many care navigators are also trained therapists and doctors. Venetian and other navigators of maritime republics distributed then the goods through Europe. They were discovered by Genoese and Portuguese navigators around 1456. Air Observers were later called "navigators".