meetings - Space Flight Mechanics Committee

9:00 AAS Switching Angular Velocity Observer for Rigid-body Attitude Stabilization
13-216 and Tracking Control
Apurva Chunodkar, The University of Texas at Austin; Maruthi Akella, The
University of Texas at Austin
This paper provides a new switching observer formulation to the classical rigid body
attitude tracking control problem in the absence of angular rate measurements. Exponential
convergence of state estimation errors is proven using a novel velocity estimation error
definition through use of this switching-type observer. The observer is independent of
controller design. Further, the maximum number of switches required by the observer is
shown to be finite. A ``separation property" type result is established, wherein a
proportional-derivative controller utilizes angular velocity estimates from the proposed
switching observer, ensuring almost global asymptotic stability for the closed-loop error
dynamics.
9:20 AAS Quaternion-based Backstepping for Line-of-Sight Tracking of Satellites Using
13-483 Only Magnetorquers
Deepti Kannapan, Indian Institute of Technology; Sandipan Bandyopadhyay, Indian
Institute of Technology; Arun Mahindrakar, Indian Institute of Technology
9:40 Break
A new strategy for the design of tracking control laws is presented for line-of-sight (LoS)
pointing control of satellites that use only magnetorquers. This strategy makes use of the
backstepping approach, and applies to satellites that require the LOS of a single instrument,
such as a transmission antenna or camera, to be pointed at a given time, but not both
simultaneously. Asymptotic stability of the desired trajectory is proved, provided the target
pointing-direction lies outside some critical range. A control law so developed is
numerically simulated for a nanosatellite mission scenario to demonstrate feasibility.
10:05 AAS Experimental Characterization of a Miniature Laser Rangefinder for
13-480 Resident Space Object Imaging
Bogdan Udrea, Embry-Riddle Aeronautical University; Michael Nayak, Space
Development & Test Directorate, US Air Force; Ayham Baba, Embry-Riddle
Aeronautical University; Timothy Grande, Embry-Riddle Aeronautical University;
Kristia Harris, Embry-Riddle Aeronautical University; Christian Castillo, Embry-
Riddle Aeronautical University; Joseph DiGregorio, Embry-Riddle Aeronautical
University; Timothy Zuercher, Embry-Riddle Aeronautical University
This paper is focused on the use of experimental test data to characterize errors inherent
within the MLR100. The algorithms developed for RSO imaging that parse the LRF point
clouds into recognizable RSO shapes employ only simple error models, including stochastic
and laser beam pulse dilation errors. The stochastic errors are modeled as normal
(Gaussian) distributions and the pulse dilation errors as a linear function of the slope of the
surface with respect to the LRF receiver optical axis. Results of the experiments and test
data discussed in the current work are directly applicable to constraining error models.
23 rd AAS / AIAA Space Flight Mechanics Meeting Page 21