Systron Donner Inertial (SDI) is a company that manufactures micro-electro-mechanical system (MEMS) inertial sensors and systems. It offers accelerometers, inertial measurement units, inertial navigation systems products, etc. The company provides solutions for guidance, navigation, control, pointing, and stabilization applications in commercial and military aircraft, unmanned autonomous vehicles, land vehicles, precision-guided weapons, and industrial and marine platforms.