), one can deduce the local co-latitude See also Acronyms and abbreviations in avionics Heading indicator, also known as direction indicator, a lightweight gyroscope (not a gyrocompass) used on aircraft HRG gyrocompass Fluxgate compass Fibre optic gyrocompass Inertial navigation system, a more complex system that also incorporates accelerometers Schuler tuning Binnacle Notes References Bibliography : "Gyroscopic compass" by E. A. Sperry, filed June, 1911; issued September, 1918 External links Feynman's Tips on Physics - The gyrocompass Case Files: Elmer A. Sperry at the Franklin Institute contains records concerning his 1914 Franklin Award for the gyroscopic compass 1908 introductions Navigational equipment Avionics Aircraft instruments German inventions