(Georgia Institute of Technology, 2013-01)
Dutta, Soumyo; Braun, Robert D.; Karlgaard, Christopher D.
Mars entry, descent, and landing (EDL) trajectories are highly dependent on the vehicle's aerodynamics and the planet's atmospheric properties during the day-of- flight. A majority of previous EDL trajectory and atmosphere reconstruction analyses do not simultaneously estimate the flight trajectory and the uncertainties in the models. Adaptive filtering techniques, when combined with the traditional trajectory estimation methods, can improve the knowledge of the aerodynamic coefficients and atmospheric properties, while also estimating a realistic confidence interval for these parameters. Simulated datasets with known truth data are used in this study to show the improvement in state and uncertainty estimation by using adaptive filtering techniques. Such a methodology can then be implemented on existing and future EDL datasets to determine the aerodynamic and atmospheric uncertainties and improve engineering design tools.
(Georgia Institute of Technology, 2012-08)
Dutta, Soumyo; Braun, Robert D.; Karlgaard, Christopher D.
The Mars Science Laboratory (MSL) contains an atmospheric data system that takes
measurement of the pressure distribution on the entry body during the hypersonic and
supersonic descent phases of the flight. This pressure data can be combined with other on-
board sensors, such as accelerometers, gyros, and radar altimeter, to estimate the flight's
trajectory, aerodynamics and the atmospheric profile. The number of sensors and their
locations for the atmospheric data system can be optimized to increase the accuracy of
the post-flight reconstruction. Methodologies based on using the estimation residual and a
surrogate of the observability matrix are presented here and results of the optimization exercises for pressure transducer systems on Mars entry, descent, and landing (EDL) vehicles
are shown. These techniques can be subsequently applied in the design of instrumentation
suites of future EDL vehicles.