If you have questions about our products you own, Fill out the form below and we will answer any questions you have. Tips: Fields marked with*are required. Dynamically Tuned Inertial Navigation System ER-1 (0.4~0.5°): ◆Strapdown inertial navigation system determination of aircraft position, heading, altitude; ◆System with emergency rapid alignment, normal alignment, navigation, correction, parameter calibration, testing, parameter binding, non volatile storage.