Development of a Lunar Astronaut Spatial Orientation and Information System (LASOIS)

In future lunar exploration, spatial disorientation may become an increasingly critical issue for astronauts as the area of exploration increases from several kilometers in the Apollo missions to over one hundred kilometers from the main base station in future landed missions. To address this problem, the Mapping & GIS Laboratory at The Ohio State University, working with partners, is developing a Lunar Astronaut Spatial Orientation and Information System (LASOIS) designed to provide astronauts with continuous navigation updates. Due to specific environmental conditions on the lunar surface (lack of familiar landmarks, ambiguous depth and shading cues, etc.), a multiple-sensor approach is proposed to overcome challenges to astronaut orientation. In this approach, data from on-suit sensors (stereo cameras, MEMS Inertial Measurement Unit (IMU), and foot-mounted pressure sensors) and from off-suit sensors (Lunar Reconnaissance Orbiter Camera) are integrated through an Extended Kalman Filter (EKF). The Zero Velocity Update (ZUPT) technique is used to compensate for distance errors while data from vision sensors are used to compensate for any IMU gyro drift. The spatial information generated by this integrated-data approach will be provided to astronauts through a wrist-mounted OLED (Organic Light-Emitting Diode) interface. Extensive field tests incorporating all of the above-mentioned sensors were performed in a Lunar-like environment at Moses Lake, WA. When compared to GPS-derived ground truth, the trajectory generated by the developed system was found to have a disclosure of 6 m for a total traverse of 107 m (5.6% accuracy). By integrating additional sensor systems (tactical grade IMU, radio-frequency identification beacons, star tracker) and improving data-processing algorithms, it is expected that this system ultimately will be able to achieve a disclosure of less than 2% overall.