The application and future development of a MEMS SiVS® for commercial and military inertial products

BAE Systems has been developing Coriolis vibratory gyros for over 15 years. The latest gyro to emerge from this development uses a silicon MEMS sensor, SiVSG®. This is an evolutionary development from earlier ceramic cylinder and metal ring VSGs, produced by BAE Systems. SiVSG® is being mass-produced for the commercial and automotive rate sensor market. SiVSG®´s immunity to vibration and shock has enabled its application in advanced braking systems on automobiles. BAE Systems has now leveraged the high volumes from the automotive and commercial market to introduce next generation, low cost gyro products into the military and aerospace sectors. BAE Systems is using these SiVSG® as the basis of a family of single-axis rate sensors (SiVSG®) and Inertial Measurement Units (SiIMU™) that are aimed at defense and aerospace applications. The robust structure of the gyro has allowed it to survive and operate after a 23,000g gun-launch shock. Variants of SiJMU™ have been selected for a number of guided missile programs such as the UK Vertical Launch Seawolf Missile system and the US Navy Extended Range Guided Munition (ERGM). This paper describes the performance of SiVSG® technology as applied to SiIMU™. Future technology and product development strategy is outlined. The development of a digital gyro drive circuit is described, and its implementation in both a rate integrating gyro (SiRIG™) and a variable rate range gyro (SiVRG®) for high roll rate platforms. Current and projected performance of SiIMU™ is presented, together with the strategy for integration with GPS.