Temperature Variation Analysis of the STIM300 Inertial Measurement Unit

A key navigation instrument found on most autonomous and semi-autonomous platforms is the inertial
measurement unit (IMU). This type of sensor is a combination of microelectromechanical systems (MEMS) that
provide inertial information to the navigation system. Typical MEMS hardware include a gyroscope and an
accelerometer (for rates and accelerations, respectively) within a single platform. The Near Earth Asteroid (NEA)
Scout mission, slated to launch in October of 2018 (Author’s note: NEA Scout ultimately launch on November 16,
2022), carries an on-board IMU from Sensonor. This particular model has yet to see spaceflight, and questions about its on-orbit reliability remain. Dynamic tests were produced in the summer of 2016 by a visiting faculty member from Arkansas Tech University, Daniel Bullock. During these experiments, concerns about the noise characteristics of the sensor were raised, specifically relating to how temperature fluctuations affected the unit. It was found that the IMU took an extended period of time before reaching an internal steady state temperature. These tests often displayed large temperature variations, making the calculation of noise characteristics, such as bias drift, difficult to attribute entirely to noise. Static and dynamic tests were re-performed under more stringent constraints on temperature. Tests reported herein conclude that the IMU is adequately capable of providing inertial information for the NEA Scout mission.