High-end inertial navigation demonstration based on MEMS accelerometers

Thanks to the breakthrough brought by the Hemispherical Resonator Gyroscope (HRG), Safran Electronics & Defense has been introducing the most efficient navigation-grade Inertial Navigation Systems (INS) in terms of C-SWaP (Cost, Size, Weight and Power), with products such as: •Onyx, high-performance land and sea inertial reference system ([1]) •Skynaute, ultra-compact hybrid navigation system for helicopters, UAVs and aircrafts ([2]) •Spacenaute, high-end inertial measurement unit for space launchers, qualified on Ariane6. By pairing HRG Crystal™ and macro-sized pendulous accelerometers, those products have already proven their ability to achieve the highest navigation performance, with better C-SWaP characteristics than optical gyroscope technologies (FOG and RLG), and much higher reliability. In order to move forward and push back the limits of integration capability of inertial navigation systems, Safran Electronics & Defense has been working for several years on the development of a new generation of navigation-grade, MEMS-based closed loop accelerometers ([3], [4]). Through their combined expertise, Safran Electronics & Defense and its daughter-company Safran Sensing Technologies Switzerland (formerly known as Safran Colibrys) have now brought this new sensor design to life, and the sensor is already in production in Safran's factories. Previous presentations ([3]) showed the performance of this new accelerometer at sensor level, along with Safran's capability to mass-manufacture such accelerometer. Following the outstanding results obtained at sensor level, this new generation of accelerometers has been paired with HRG Crystal™ to design a new generation of Inertial Navigation Systems. This paper presents the key design criteria of such inertial core, along with experimental performance evaluations results of the Inertial Navigation Systems in which it is integrated, on various types of platforms and mission profiles, such as: –North Finding –Navigation on airborne platforms –Land navigation In particular, the results will focus on orientation and position accuracy in pure inertial modes, this showing the absolute resilience of such position and navigation solution to GNSS-denied conditions. A particular focus will also be given to robustness tests on the accelerometer, and associated experimental results.