Quartz pendulous accelerometers for navigation and tactical grade systems

Accelerometers which are integrated into navigation, guidance or piloting systems are required to meet very demanding performance requirements in terms of accuracy, stability and linearity. Typically these requirements must be achieved under stringent conditions, at sea, on land, in air, and over the full life cycle of the system. Therefore not surprisingly, only two technologies so far have risen to the challenge and have demonstrated the right capabilities: Vibrating Beam Accelerometer technology and Quartz Pendulous Accelerometer technology. Since their roll out in the '90s, Quartz Pendulous Accelerometers rapidly became the most widely used accelerometers for high grade navigation applications and this position remains largely unchallenged to this time. InnaLabs® Ltd. is a privately held limited company which was incorporated in Ireland in 2011. The Company has recently completed the development of a range of specialist precision Quartz Pendulous Accelerometers which are today used in a variety of navigation and tactical applications. After a brief description of the basic physical principles and an overview of the key manufacturing processes developed by Innalabs, such as the quartz wet etching, this paper provides statistical results recorded on the AI-Q-2010, AI-Q-1410 and AI-Q-710 accelerometer variants. These three part numbers are currently in full series production in Dublin. Some key performance parameters are presented, such as the bias and scale factor stability over temperature and over time, the short-term bias stability (measured using the Allan variance method), the output noise, and the sensitivity to shock and vibration. The results presented here demonstrate the capabilities of the InnaLabs® Quartz Pendulous Accelerometer range. These products provide a European source of high grade accelerometers for applications requiring navigation and tactical grade performance.