Austin, Texas, United States
I specialize in modeling and estimating nonlinear stochastic processes that can be represented with stochastic differential equations. To date I have applied these techniques to space applications, mainly orbit and attitude determination and autonomous spacecraft navigation; however my experience is applicable to any field where there is stationary or non-stationary uncertainty. I am interested in modeling, quantifying, and estimating any process, the more challenging, nonlinear and complicated, the better! I also have experience in engineering management and project management.
Led a team of navigation engineers in developing the navigation subsystem for the human lunar lander, the effort included all phases of flight: lunar transfer, RPO, DDL, Ascent, and vision-based navigation.
Orion Exploration Mission 1 and 2 (EM1 and 2, later renamed Artemis 1 and 2) absolute navigation (12/2013 to 1/2017) Reviewing and upgrading the absolute navigation system architecture, design, and analysis in preparation for the Preliminary Design Review (PDR) • Responsible for upgrades to the Exploration Flight Test software to meet new mission requirements • Successfully completed GNC subsystem delta PDR • Designed and coded the initial implementation of two high rate EM1 navigation Computer Software Units: Delta Velocity-Delta Angle Accumulator (DVDAAccum) and Position and Velocity Propagator (PVPropFast) • Designed, coded, and unit tested three low rate EM1 navigation Computer Software Units: Atmospheric Extended Kalman Filter (AtmEKF), Earth Orbit EKF (EOEKF), and Cislunar EKF (CLEKF)
Lead 10 members of the technical staff plus summer interns and graduate research fellows in developing guidance, navigation, and control systems, modeling, and simulation for spacecraft and launch systems. Group members contributing to International Space Station, DARPA Phoenix Program, NASA's Orion Vehicle, Sierra Nevada's Dream Chaser Vehicle, Orbital's Cygnus Vehicle, NASA's Space Launch System. Established R&D collaboration with the Johnson Space Center for spacecraft rendezvous and vision navigation technologies. Managed university collaboration program with Rice University, personally supervised 5 students and recruited/oversaw 3 other.
Draper laboratory is part of the Orion Absolute Navigation team and provides design and analysis support to the Orion Project. Four Draper people, including myself, work this task. My role as task leader is to interact with the NASA team leader to staff Draper personnel, overview the products of Draper people and insure they have the resources they need to deliver them on schedule, and track expenditure to insure the task stays on budget. Since I took over this task its scope and size have consistently grown. Besides the task management I am personally responsible for the extended Kalman filter (EKF) and the filter navigator (FiltNav) computer software units (CSUs), in this capacity I completed the following tasks • Coded the algorithms in Simulink to satisfy FSW coding standards • Included error handling logic • Conducted unit tests of CSUs to verify algorithm correctness and path coverage • Introduced a method to implement underweighting and consider capabilities to the UDU formulation of the EKF • Aided the parameter selection of the CSUs (“filter tuning”)
Dream Chaser’s Absolute Navigation (11/2012 to 11/2014) Responsible for overview of design and flight software generation as well as principal designer of the Fault Detection and Isolation (FDI) algorithms • Created navigation simulation environment to support algorithm generation and testing • Designing Inertial Measurement Unit (IMU), GPS, and Radar Altimeter FDI computer software units • Responsible for flight software generation Orion Crew Exploration Vehicle (CEV) Relative and Celestial Navigation (10/2007 to 9/2011) • Assisted in analysis and design of the relative navigation system and autonomous lunar navigation for NASA Orion Vehicle • Responsible for relative navigation flight-software domain (January 2011 to September 2011) • Designed and analyzed the relative attitude navigation system and delivered Matlab/Simulink prototype flight software (January 2009 to September 2011) • Assessed feasibility and analyzed performance of the backup optical navigation system during lunar return; assessed performance and determined optimal optical sensors utilization for achieving entry interface safety requirements (October 2007 to December 2008) • Supported integration of relative navigation in the rendezvous and proximity operation simulation scenarios Relative Navigation of Cygnus Vehicle (6/2008 to 12/2010) Responsible for design of onboard navigation system for the Orbital Sciences Corporation commercial orbiting transportation system • Developed relative navigation performance requirements for safe and successful proximity operations and birthing with the International Space Station • Designed and analyzed performance of the relative GPS and LIDAR filters for autonomous proximity operations and berthing with the International Space Station • Developed Matlab/Simulink prototype flight software to be autocoded into flight software • Performed algorithm and flight software verification and validation