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Ancil Marshall

Ancil Marshall

Senior Guidance Navigation and Controls Engineer

Guidance Navigation and Controls
Aircraft, Spacecraft, Orbital Dynamics
Modeling and Simulation
48 years old
Boston (02108) United States (Massachusetts)
Employed Open to opportunities
Senior Guidance, Navigation and Controls (GNC) Engineer with over fifteen years of experience specializing in aircraft, missiles, launch vehicles, space vehicles and commercial drones. Expert in a wide-range of GNC responsibilities such as the modeling of aerospace vehicles, the design and analysis of feedback control laws, the development of guidance algorithms, the analysis of mission performance via simulations, the support of vehicle integration tests and on-site, in-field flight activities.

Strong project management skills demonstrated by leading various programs and heading up small multi-disciplinary teams for diverse projects. Firmly believes in team development through collaboration, training and mentoring.

Open to new opportunities in a GNC flight controls group where I can leverage my experience to ensure the success of challenging projects.
  • GNC Lead for a Boeing 777X autonomy project. Manages a small team of GNC and Software Engineers to develop an independent autonomy, autoflight and primary controls function to aviate the 777X.
  • Designs SISO and LQR controllers, as well as guidance algorithms for the 777X using Model Based Design (MBD) in Matlab/Simulink. Applies DO178C and DO331 standards. Auto-generates and implements code into 777X nonlinear desktop and cab simulator.
  • Performs 777X GNC controller architecture designs using Model Based System Engineering (MBSE) techniques to meet operational and safety requirements.
  • Leads customer interactions on the 777X project (e.g., demos, on-site meetings). Manages project milestones, schedule and agile sprints. Coaches team members.
  • Lead GNC Engineer for Centaur - an autonomous, optionally-piloted, twin-engine airplane for ISR operations.
  • On Centaur, works with multi-disciplinary team to plan flight tests, post-process flight data and resolve flight anomalies.
  • Works with Centaur Chief Engineer to define requirements and statement of work for the vendor-supplied GNC controllers and guidance algorithms.
  • Lead GNC Engineer for an Urban Air Mobility eVTOL project. Lead team of two GNC engineers during preliminary studies, derived nonlinear hover equations, designed LQR controller and performed rotor failure study.
Company website
  • Researcher and developer of future guidance algorithms for Parrot's Drones. Simulated proof of concept guidance algorithms in Matlab and Python.
  • Implemented proof of concept guidance algorithms in C/C++ embedded software on the Bebop 2 and Anafi drones.
Company website
  • Software Lead of the iOS mobile application for the Neuronaute - a wearable connected medical device to detect epilepsy. Deputy lead of the mobile group of eight developers.
  • Implemented new functions using existing application architecture and libraries (BLE, TCP/IP, database, GUIs).
  • Improved stability of TCP/IP connection and debugged race-condition. Developed real time graphics library. Reduced CPU usage by 50%.
Detailed Description
  • Worked closely with embedded software, cloud, and data science departments.
  • Mentored new hires
  • Authored software quality documents. Performed quality tests.
Company website
  • GNC Engineer on GQM-163A missile. Managed linear analysis tools, conducted nonlinear 6DOF simulations in C++, performed vehicle integration tests, investigated flight anomalies and recommended software fixes.
  • Lead GNC Engineer for High Diver variant of GQM-163A. Performed GNC design from the initial concept to the eventual launch.
  • Lead GNC Engineer on FFMS variant of GQM-163A and traveled to Ile du Levant, France with multi-disciplinary team to perform launch operations.
  • Parameterized GQM's time-scheduled flight gains to a Mach and mass-based adaptive algorithm.
  • Developed various guidance algorithms for the High Diver variant of GQM to improve its performance and robustness.
  • Created Simulink model of the High Diver gas generator, which successfully matched motor tests.
  • Worked with aerodynamics group to simplify a 5D High Diver model into a 2D model in order to embed the reduced model in flight software.
  • Performed independent reviews of the Minotaur I, Pegasus and Antares space launch vehicles, the Orbital Boost Vehicle, and the Patriot Target Vehicle.
  • Lead GNC Engineer for the Zombie Pathfinder program, a single-stage and a two-stage ballistic missile for NASA's Sounding Rocket Program. Performed initial design trade studies, improved 6DOF nonlinear simulations.
  • Mentored other engineers in GNC and C/C++ 6DOF simulation. Taught GNC course to a group of forty engineers.
  • Utilized Simulink engine model tool to analyze, design and test engine controllers.
  • Performed system identification and control design of a Robust Particulate Diesel Filter.
Detailed Description

Graduate Research Assistant

Georgia Tech
August 2000 to May 2003
United States - Georgia
  • Developed linear and nonlinear controllers to stabilize the angular velocity of a spacecraft with one Variable Speed Control Moment Gyro (VSCMG).
  • Authored OpenGL program to visualize attitude of spacecraft.
  • Marshall, A. & Tsiotras, P. - “Spacecraft Angular Velocity Stabilization Using a Variable Speed Control MomentGyro,” AIAA Paper 03-5654, AIAA Guidance, Navigation & Control Conference, Austin, TX, 2003.