A DSP Approach to Interpolate Fast Maneuver Profiles of the NASA Lunar Reconnaissance Orbiter
Abstract
The NASA Lunar Reconnaissance Orbiter (LRO) began using two star trackers as a primary means of attitude determination following the imminent failure of its inertial measurement unit in 2018. New types of maneuver trajectories that steer the star trackers around the keep-out regions are needed to ensure stability of the attitude determination filter. The new mode of operation necessitates the need for the LRO conventional quaternion error feedback controller to operate as an attitude tracking system opposed to a traditional attitude regulator. However, the LRO is not equipped to support the transition because its command buffers are not large enough to store the time-varying attitude commands. This thesis explores and recommends a solution for NASA to install a uniquely designed digital signal processing (DSP) based interpolation filter that enables the time-varying attitude command data to be compressed to a tolerable size. The recommended filter is a practical implementation of a spline interpolator that leverages functionality of the existing flight software. A Kalman Filter is used to optimize the filter inputs to minimize interpolation error of the command trajectories. High-fidelity simulations were conducted on the recommended filter to illustrate the overall performance and 50:1 data compression (or more) can be achieved. The results of this thesis are currently being implemented by NASA to facilitate a transition of FastMan to a fully operational status.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2022
- Accession Number
- AD1221939
Entities
People
- Joshua A. Levitas
Organizations
- Naval Postgraduate School