An integrated MEMS inertial measurement unit

Abstract

With MEMS technologies, instrument subcomponents are integrated in the design to form individual gyroscopes and accelerometers on a single chip. This replaces the assembly of individual subcomponents which forms conventional instruments. Similarly, MEMS instrument components can be integrated to form complete inertial measurement units (IMUs). Integration is the only practical approach to realizing low cost and small size units, largely because both instrument and IMU assembly and instrument alignment tasks are eliminated. The obstacle to success is the lack of fabrication process maturity which limits the yield of satisfactory devices which, in turn, very severely limits the yield and escalates the cost of systems that require six working devices on the same chip. The solution to this problem is to base the IMU on instruments with a common design so that the fabrication process variations produce similar effects on each of the instruments. The IMU performance can be optimized by exploiting the commonality between instruments.