CV: GNC Engineer



Personal information
Contact information
Candidate Profile
 Date Submitted:01-01-2012
 Last Modified:01-01-2012 (07:23)
Job information
 Current job:GNC Engineer
 Employment Term:Either
 Job location:Own country
 Date available:immediately
 Industry:Satellite Manufacturers and Subcontractors, Satellite Operators, , , Launch Systems
 KeywordsI am the only GNC Engineer able to tune guidance and control systems for complex aerospace maneuvers without using gain scheduling.
Guidance, Navigation, and Control Algorithms ~ Software Development ~ Computational Theory and Design ~ System Analysis and Simulation ~ Proposal Development
Secret Security Clearance 
Linear Time Invariant (LTI) Six Degree of Freedom Differential Equations:
Only scientist/engineer in the world who can devise GNC algorithms for difficult aerospace maneuvering scenarios without using gain scheduling or other types of nonlinear control.
Currently developing a full fidelity 6-DOF state feedback control loop with constant gains using quaternion mathematics to separate inertial and body rotational dynamics.
Also developing a quaternion Kalman filter with constant Kalman gains.
Guidance, Navigation, and Control (GNC) Engineer                                    2010 to 2011
Masten Space Systems, Mojave, CA
Six degree of freedom (6-DOF) suborbital vertical takeoff vertical landing (VTVL) rocket flight simulation
o Created flight profiles up to 30 km in altitude in preparation for NASA CRuSR launches.
o Modified vehicle properties (mass properties, engine characteristics, rcs, etc.) and analyzed simulation results for new suborbital VTVL rocket to ensure attitude control system stability and nominal mission conditions.
o Determined abort and terminate parameter limits using simulation trajectory results.
Hardware in the Loop (HWIL) simulation
o Validated flight profiles up to 5 km in altitude for NASA CRuSR launches.
o Analyzed simulation results for planned vehicle flight tests to ensure parameters were properly set.
o Validated abort and terminate parameter limits using simulation results.
Operational engine/vehicle testing
o Issued commands remotely to onboard flight management system (activating/deactivating valves, testing various engine components, initiating engine ignition) during field testing.
o Created a checklist with step by step instructions for rocket flight preparations and suggestions for dealing with off nominal conditions.
NASA SBIR Proposal Submission (Navigation Flight Dynamics Software and Technologies Topic)
o Proposed using a quaternion exponential Kalman (QEK) filter to map the nonlinear state equations to an equivalent linear space to meet NASA’s objective of improving the navigation filter for GNC systems.
Guidance, Navigation, and Control (GNC) Engineer                               2008 to 2009
Miltec Missiles and Space, Huntsville, AL
Foreign anti-tank 6-DOF missile simulation
o Debugged and modified existing 6-DOF missile simulation developed in C++.
o Tested simulation autopilot with step commands, zero acceleration and step acceleration commands.
o Modified and debugged line of sight (LOS) proportional derivative guidance subroutine using azimuth and elevation angles to the missile and target, including guidance gain tuning for trajectory optimization.
o Integrated missile simulation into a package containing a scene generator and a missile/target tracker, including synchronizing the different applications and retuning the guidance gains.
o Developed a roll autopilot to keep the missile at a zero roll angle.
o Shot missile ten degrees off boresight from the target to test the guidance system and autopilot.
Upper atmospheric hypersonic glider 6-DOF simulation
o Conducted linear stability analysis on glider endo- and exo-atmospheric maneuvers.
o Conducted research into and began development of a dynamic inversion autopilot.
o Began applying quaternion exponentials to autopilot design to improve control system robustness
Doctoral Student Research Assistantship, Old Dominion University, Norfolk, VA                           2003 to 2008
Invented a new type of eigenvalue for quaternion mathematics to facilitate development of a linear time invariant (LTI) set of 6-DOF equations.  Currently formulating a quaternion frequency domain method of solution.
Dissertation research in inertial guidance, navigation and attitude control.
Presented conference papers at professional AIAA conferences/exhibits.
Research Scientist and Engineer (Mathematician)                                         1990 to 2003
Naval Surface Warfare Center, Dahlgren Division, Dahlgren, VA                                                               
SLBM Research and Analysis Division
o Developed a simulation for an experimental flapped re-entry body and analyzed the resulting trajectory.  
o Reduced 6-DOF reentry simulation execution time by two-thirds by fitting a time varying sine wave to the quaternion components and switching the state vector from angular velocity to quaternion first derivative.
o Investigated further 6-DOF modifications using quaternion mathematics.  
o Developed methods of optimizing EMP attacks.
o Researched application of genetic algorithms, simulated annealing, and other combinatorial algorithms to sequencing and grouping of missile attacks.
o Analyzed terrain effects on the fuzing system, and conducted other fuze studies.
o Developed a graphical program for analyzing plume impingement on re-entry bodies.
SLBM Software Development Division
o Developed various systems and applications software programs.
o Replaced the Runge-Kutta method with a predictor-corrector method in a 6-DOF re-entry simulation in the upper part of the atmosphere and combined with other modifications to reduce the execution time by 85%.
o Developed an object-oriented 6-DOF re-entry simulation.
Career Note: Additional Position as Systems Engineer (Contractual) for Aerodyne Industries, LLC 
Antares six degree of freedom launch vehicle simulation
o Added Monte Carlo capabilities for mass properties dispersions of launch vehicle elements.
Ph.D. in Aerospace Engineering, Old Dominion University, admitted to candidacy, expected graduation              Fall 2011
Norfolk, VA
Ph.D. work in Computational Sciences and Informatics (Mathematics track), George Mason University,            1995-2000
Fairfax, VA
Master of Science in Computer Science, Virginia Polytechnic Institute and State University,                      December 1994
Blacksburg, VA
Bachelor of Science in Mathematics (computational track), Pennsylvania State University, State College, PA    May 1990
Davailus, G.P.; “Linear Time Invariant Formulation of the Gyroscopic Problem using Quaternion Mathematics”. AIAA-2011-1224, 49th AIAA Aerospace Sciences Meeting; Orlando, FL., January 2011
Davailus, G.P.; Newman, B.A.; “The Application of Quaternion Algebra to Gyroscopic Motion, Navigation, and Guidance”, AIAA-2005-5945, AIAA Guidance, Navigation, and Control Conference and Exhibit; San Francisco, CA., August 2005
Davailus, G.P.; “The Transformation of Oscillatory Equations in Six Degree of Freedom Trajectory Simulations Involving Coordinate Transformations”, M.S. Thesis, Department of Computer Science, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, 1994.

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