Shock Hardened Inertial Measurement Unit (SHIMU)

The team of ATA and SNL is developing the Shock Hardened Inertial Measurement Unit (SHIMU) with robust MEMS inertial components that can survive severe shock and vibration loads and operate effectively during the launch sequence and high-G maneuvers typical of missile defense applications.Enabling technologies include very high aspect ratio proof mass suspensions that provide high out-of-plane motion rejection and reduced quadrature error.We have developed a motion sensing device that promises sensitivity levels on the order of femtometers, which allows the proof mass suspension system to be made much stiffer while retaining the ability to detect small deflections.SHIMU will employ temperature stabilization through micro-ovenization to improve bias and scale factor stability.The thermal and mechanical isolation afforded by this approach will help alleviate misalignment problems arising from structural stresses associated with the assembly and mounting processes as well as those created by temperature variations occurring after assembly.The range of motion of the proof mass will be constrained to the linear region of the sensor by the method of force rebalancing using an improved electrostatic actuation technology that can generate high forces with lower voltages, significantly reducing force related errors.