Autonomy & Software Senior Guidance, Navigation & Controls (GNC) Engineer Remote (US) · $130K–$210K →

Grex Defense, Inc.; Northern (KY); Hybrid; USD 120,000 - 180,000; Full time

Job summary

Grex Defense, Inc. seeks a Senior GNC Engineer to architect, develop, and test inner-loop flight controls for a new autonomous aircraft.

You will build the control architecture, simulation, and hardware integration from concept to flight test. As an early member of the engineering team, you will shape GNC workflows, develop toolchains, and set software practices while collaborating with aerodynamics, avionics, propulsion, and test.

Qualifications

• Bachelor's degree in Aerospace, Mechanical, Electrical Engineering, Robotics, Controls, or related.
• Significant professional experience developing GNC, flight-control, robotics, or autonomous systems.
• Experience taking a vehicle from modeling and simulation through hardware integration and testing.
• Expert knowledge of inner-loop flight controls: rate, attitude, velocity, and position.

Responsibilities

• Architect, develop, and test inner-loop flight controls for autonomous aircraft.
• Develop the simulation and analysis environment for control development.
• Integrate controls with real hardware and prove systems through ground and flight test.
• Establish GNC workflows, simulation architecture, tools, and software practices.
• Collaborate with aerodynamics, vehicle design, autonomy, avionics, propulsion, and test teams.

Skills

GNC development

Flight control

Modeling & simulation

PID tuning

C/C++

Python

State machines

System identification

Education

Bachelor's degree (Aerospace/Mechanical/Electrical Engineering, Robotics, Controls)

Tools

MATLAB/Simulink

Job description

Architect, develop, and flight-test the inner-loop flight controls for a new class of autonomous aircraft — from blank-sheet control laws and simulation through hardware integration and test.

Grex Defense builds autonomous systems for air dominance. The character of conflict is changing, with autonomy, mass, and software now deciding outcomes. The advantage goes to whoever can field new capability first, and Grex Defense exists to provide rapid capability solutions for hard defense problems.

Grex Defense is seeking a Senior Guidance, Navigation & Controls (GNC) Engineer to help architect, develop, implement, and test the flight controls for a new class of autonomous aircraft. This is a hands‑on role for someone who wants to work from a blank sheet — developing the inner‑loop control architecture, building the simulation and analysis environment, integrating controls with real hardware, and proving the system through ground and flight test.

As an early member of the engineering team, you will do more than develop control laws. You will help establish our GNC workflows, simulation architecture, development and test toolsets, software practices, and technical standards, working directly with aerodynamics, vehicle design, autonomy, avionics, propulsion, and test to influence the aircraft while it is still being defined.

Startup life at Grex means moving quickly between analysis, simulation, software, hardware, and the vehicle itself. We are looking for an engineer comfortable making decisions with incomplete information, building the tools needed to answer difficult questions, and rapidly folding what we learn from simulation and test back into the design.

What we look for:

• Bachelor's degree in Aerospace, Mechanical, or Electrical Engineering, Robotics, Controls, or a related technical discipline.
• Significant professional experience developing GNC, flight-control, robotics, or autonomous vehicle systems.
• Demonstrated experience taking a vehicle or robotic system from modeling and simulation through hardware integration and real‑world testing.
• Expert knowledge of inner‑loop flight or vehicle controls: rate, attitude, velocity, and position control.
• Expert knowledge of linearization, PID architecture and tuning, gain scheduling, loop shaping, filtering, stability margins, and frequency‑domain analysis.
• Strong understanding of rigid‑body dynamics, nonlinear systems, state‑space methods, MIMO systems, controllability, observability, and modal behavior.
• Strong experience with MATLAB and Simulink for dynamic‑system modeling, controls development, analysis, and simulation.
• Experience developing and working with nonlinear 6‑DOF vehicle simulations.
• Strong understanding of state‑machine architectures, mode transitions, command arbitration, fault handling, and degraded vehicle behaviors.
• Experience modeling actuator dynamics, bandwidth, rate and position limits, saturation, nonlinearities, and time delays.
• Experience accounting for sensor, computational, communication, and actuator latency in closed‑loop systems.
• Strong understanding of system identification: excitation design, parameter estimation, model correlation, and validation using test data.
• Experience developing test harnesses and systematic verification methods for control systems.
• Working proficiency in C/C++ and Python for controls, simulation, embedded implementation, automation, or test.
• Experience analyzing high‑rate telemetry and diagnosing discrepancies between models, software, hardware, and real‑world vehicle behavior.
• Ability to work across disciplines and influence aircraft configuration, aerodynamics, propulsion, avionics, actuators, sensors, autonomy, and test.
• Willingness to remain deeply hands‑on and support vehicle integration, ground testing, and field operations.
• U.S. person status under U.S. export‑control law (ITAR/EAR).