Elmer Ambrose Sperry, American inventor, co-invented the gyrocompass (born 1860)

Elmer Ambrose Sperry Sr. was an American inventor and entrepreneur, most famous for construction, two years after Hermann Anschütz-Kaempfe, of the gyrocompass and as founder of the Sperry Gyroscope Company. He was known as the "father of modern navigation technology".

A gyrocompass is a type of non-magnetic compass which is based on a fast-spinning disc and the rotation of the Earth to find geographical direction automatically. A gyrocompass makes use of one of the seven fundamental ways to determine the heading of a vehicle. A gyroscope is an essential component of a gyrocompass, but they are different devices; a gyrocompass is built to use the effect of gyroscopic precession, which is a distinctive aspect of the general gyroscopic effect. Gyrocompasses, such as the fibre optic gyrocompass are widely used to provide a heading for navigation on ships. This is because they have two significant advantages over magnetic compasses:

• they find true north as determined by the axis of the Earth's rotation, which is different from, and navigationally more useful than, magnetic north, and
• they have a greater degree of accuracy because they are unaffected by ferromagnetic materials, such as in a ship's steel hull, which distort the magnetic field.