High-Performance Triaxial MEMS Accelerometer for Applications with Harsh Environmental Conditions

This work presents the next generation of NG LITEFs closed-loop microelectromechanical (MEMS) accelerometer. The B–500 is a form-fit-function compatible accelerometer to the B– 295. Its performance targets demanding tactical and navigation grade applications. For use in harsh environments, a focus lies on an optimized vibration rectification error (VRE). Analytical considerations show the trade-off between velocity random walk (VRW) and VRE. The strategies used to achieve an exceptionally low VRE will be explained. For the analysis of the VRW, analytical models of the entire system are set up, which allow the different noise sources to be analyzed and the overall system to be optimized. As of today, we can report a root-mean-square (rms) bias residual error of less than 59 μg and a rms scale factor error of less than 57 ppm over a temperature range of -40°C to 85°C after accelerated lifetime tests. The Allan deviation plot shows a very good bias instability of about 1 μg at a cluster time of 400 s, while a VRW of about 15 μg/Hz is achieved. The VRE was determined with a vibration profile of 10.9 g rms in the frequency range from 10 Hz to 2 kHz. Excellent values of the vibration rectification coefficient (VRC) of less than 5 μg/g^2 can be reported for direct mounting without any shock absorber. This makes the B–500 ideal for industrial applications that require high performance under harsh environmental conditions.