Inertial+, the Once and Future Navigation System

Since their invention shortly after World War II, inertial navigation systems have proven to be indispensable in the aerospace industry. They are immune to jamming and provide position, velocity and attitude with low noise, high data rates and low data latencies. Since the 1960s, the long-term drift inherent in any inertial system has typically been corrected through the integration of an external aiding source via an extended Kalman filter. Aiding sources have varied over the decades and, although GNSS is currently the most popular choice, the future of navigation can be characterized simply as “inertial-plus.” Plus what? Whatever the best aiding source happens to be. Vision? Electro-optics? LADAR? Signals-of-opportunity? Maybe all of the above. In this lecture we will review the key operating principles of inertial navigation and will highlight the major error characteristics. The primary inertial-aiding design architectures will then be discussed along with performance considerations.