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航空航天 & 军事 : 学术学位

Resolving GPS carrier phase ambiguities for a low Earth orbit spacecraft.

The application of GPS carrier phase integer ambiguity resolution to low Earth orbit spacecraft missions has been a topic of great interest in recent years. This advanced processing technique may make it possible to achieve higher orbit accuracy for spacecraft that carry GPS receivers. The research

ASPECTS OF CONTROL OF LARGE FLEXIBLE SPACECRAFT.

In the last few years a large number of potential future spacecraft projects have been identified which require spacecraft of unprecedented size, and hence unprecedented flexibility. The attitude control problems for such spacecraft are best characterized as simultaneous pointing control and shape c

Application of the DSMC method to high density micro-flows.

This research discusses the application of the Direct Simulation Monte Carlo (DSMC) method to flows in Micro Electro Mechanical devices (MEMS) and the Space Shuttle leading edge reinforced Carbon-Carbon destruction due to the chemically active flows. For the MEMS device application an analysis to op

Elements of a collaborative systems model within the aerospace industry.

Scope and method of study. The purpose of this study was to determine the components of current aerospace collaborative efforts. There were 44 participants from two selected groups surveyed for this study. Nineteen were from the Oklahoma Air National Guard based in Oklahoma City representing the avi

Aerodynamic performance of osculating-cones waveriders at high altitudes.

The steady-state aerodynamic characteristics of three-dimensional waverider configurations immersed in hypersonic rarefied flows are investigated. Representative geometries are generated using an inverse design procedure, the method of osculating cones, which defines an exit plane shock shape and ap

Development of a test-bed for closed-loop MAV flight control .

A novel ground based test-bed for closed loop flight control of MAVs is developed. The emphasis is on easy re-programability, measurement of internal states of the vehicle, fail-safe features, and modular design so that control algorithms can be efficiently evaluated on a real MAV in flight. The sen

On the nonlinearities in the noise radiated from high-speed model jets.

The role of nonlinearity in the generation and propagation of the noise radiated from high-performance jet aircraft is not a well understood phenomenon. To address this problem, an extensive experimental program has been carried out on high-speed model jets, including both flow-field and acoustic me

Constrained model predictive control, state estimation and coordination.

In this dissertation, we study the interaction between the control performance and the quality of the state estimation in a constrained Model Predictive Control (MPC) framework for systems with stochastic disturbances. This consists of three parts: (i) the development of a constrained MPC formulatio

Flow physics of strained turbulent axial vortices.

The flow physics of strained turbulent axial vortices has been studied using direct numerical simulations (DNS) as an investigative tool. These simulations use a b-spline/Fourier spectral method. Two specific cases have been considered. A vortex that has no axial flow in its initial laminar state is

A method for scenario-based risk assessment for robust aerospace systems.

In years past, aircraft conceptual design centered around creating a feasible aircraft that could be built and could fly the required missions. More recently, aircraft viability entered into conceptual design, allowing that the product's potential to be profitable should also be examined early in th