Use of a star-aided inertial navigation system for the rimres project
- Paper number
IAC-11,A3,2.P,18,x11110
- Author
Mr. Davide Padeletti, ZARM - University of Bremen, Germany
- Coauthor
Mr. Daniel Bindel, ZARM - University of Bremen, Germany
- Year
2011
- Abstract
The aim of the german RIMRES (Reconfigurable Integrated Multi-Robot Exploration System) project is the exploration of the surface of a distant celestial body by the use of heterogeneous and cooperative mobile robots. In addition to a landing module with a fixed position, small rovers are planned to be used for the exploration of the surrounding area. They will be equipped with modular boxes which contain batteries, communication systems or scientific instruments. Due to their high mobility, the intention is to enlarge the operating range around the landing module, so that the soil and rock samples can be searched for, collected and analyzed. Therefore, for long rover operational motion in the order of several kilometers or even more, the development of a navigation system which does not require any Global Navigation Satellite System (GNSS) assistance has become of primary matter. The major idea of such a Star-Aided Inertial Navigation System was based on collecting successive images of visible stars on the sky for the absolute position determination of the rover on the planet surface. This task is achieved by performing successive measurements using a dedicated Star Sensor. Unfortunately, the vehicle does not always stand perfectly horizontally, with the result that the correct identification of the rover's inclination must be previously determined through a dedicated device. Both input measurements will be then used by the Fix Algorithm, basically a sequence of arithmetical computations, which allows the on-board computer to estimate a possible geographic position on the surface. During the rover motion, a third device, an IMU (Inertial Measurement Unit), will provide measurements of linear acceleration as well as of angular rate, whose integration leads to the actual attitude and position determination. A numerical simulation in MATLAB/SIMULINK has been taken in order to test the algorithm and then compute the final rover's state. A representative scenario for the Moon has been analyzed, using data collected from various lunar missions to determine the most up-to-date Potential Gravity Field. Its effect on the local gravity vector evaluation shows a not-negligible impact on the overall accuracy.
- Abstract document
- Manuscript document
(absent)