Browsing by Department "Aerospace Engineering and Engineering Mechanics"
Now showing items 1-20 of 215
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Ablation onset in unsteady hypersonic flow about nose-tips with a forward-facing cavity
(2001-08)A forward-facing cavity is examined as a means of reducing the severe heating and delaying ablation onset at the nose-tip of a hypersonic vehicle. Whereas previous studies have concentrated on heating rates alone, the ... -
Adaptive Estimation of Signals of Opportunity
(2014-04)To exploit unknown ambient radio frequency signals of opportunity (SOPs) for positioning and navigation, one must estimate their states along with a set of parameters that characterize the stability of their oscillators. ... -
Adaptive interplanetary orbit determination
(2000-08)This work documents the development of a real-time interplanetary orbit determination monitoring algorithm for detecting and identifying changes in the spacecraft dynamic and measurement environments. The algorithm may ... -
Adaptive output feedback controllers for a class of nonlinear mechanical systems
(2002)Even from the early days of adaptive control theory, it has been a primary target for several researchers to guarantee global stability using as limited assumptions as possible. Currently, there exist applicable theories ... -
Advanced navigation algorithms for precision landing
(2007-12)A detailed analysis of autonomous navigation algorithms to achieve autonomous precision landing is presented. The problem of integrated attitude determination and inertial navigation is solved. The theoretical results ... -
Advances in GNSS Equipment
(2010) -
Analysis and order reduction of an autonomous lunar lander navigation system
(2009-08)A navigation system for precision lunar descent and landing is presented and analyzed. The navigation algorithm is based upon the extended Kalman Filter and employs measurements from an inertial measurement unit to propagate ... -
Analysis of Ionospheric Scintillations using Wideband GPS L1 C/A Signal Data
(2004)A non-real-time GPS receiver has been developed and tested for use in scintillation analysis. The receiver consists of a digital storage receiver and non-real-time software acquisition and tracking algorithms. The goal ... -
Assessing the Spoofing Threat: Development of a Portable GPS Civilian Spoofer
(2008)A portable civilian GPS spoofer is implemented on a digital signal processor and used to characterize spoofing effects and develop defenses against civilian spoofing. This work is intended to equip GNSS users and receiver ... -
Assured Navigation and Timing
(2017-09-28) -
Attitude dynamics stabilization with unknown delay in feedback control implementation
(2009-12)This work addresses the problem of stabilizing attitude dynamics with an unknown delay in feedback. Two cases are considered: 1) constant time-delay 2) time-varying time-delay. This is to our best knowledge the first ... -
Automated generation and optimization of ballistic lunar capture transfer trajectories
(2009-08)The successful completion of the Hiten mission in 1991 provided real-world validation of a class of trajectories defined as ballistic lunar capture transfers. This class of transfers is often considered for missions to the ... -
A Blueprint for Civil GPS Navigation Message Authentication
(2014-05)A proposal for civil GPS navigation message authentication (NMA) is presented with sufficient specificity to enable near-term implementation. Although previous work established the practicality and efficacy of NMA for ... -
CASES: A Novel Low-Cost Ground-based DualFrequency GPS Software Receiver and Space Weather Monitor
(2011)GPS receivers can be used for monitoring space weather events such as TEC variations and scintillation. This paper describes the new GPS sensor developed by ASTRA, Cornell and UT Austin. The receiver is called “Connected ... -
CASES: A Smart, Compact GPS Software Receiver for Space Weather Monitoring
(2011)A real-time software-defined GPS receiver for the L1 C/A and L2C codes has been developed as a low-cost space weather instrument for monitoring ionospheric scintillation and total electron content. The so-called CASES ... -
Centimeter Positioning with a Smartphone-Quality GNSS Antenna
(2014-09)This paper demonstrates for the first time that centimeteraccurate positioning is possible based on data sampled from a smartphone-quality Global Navigation Satellite System (GNSS) antenna. Centimeter-accurate ... -
Characterization of a 50kW Inductively Coupled Plasma Torch for Testing of Ablative Thermal Protection Materials Using Non-Air Gases
(2018-05)Thermal protection systems have been a major area of study since the advent of space flight, but recent efforts towards crewed spaceflight missions have placed a new importance on the development of such systems. The 50 ... -
Characterization of Receiver Response to Spoofing Attacks
(2011)Test procedures are developed for characterizing the response of civil GPS receivers to spoofing attacks. Two response characteristics are analyzed in detail for four representative GPS receivers: (1) the spoofer power ...
