Senior GNC Engineer

About Poseidon Aerospace: Poseidon Aerospace is reimagining how the world moves goods. We build and operate full-size autonomous cargo aircraft - capable of carrying two tons of payload over a thousand nautical miles. From remote communities to contested logistics operations, our platforms unlock a new cost curve for air freight, making it faster, cheaper, and accessible anywhere it's needed. Headquartered in the San Francisco Bay Area with locations in Washington DC, Oregon, and Maine; we're building something consequential. About the role GNC is how our cargo aircraft knows where it is, decides where to go, and flies there with no pilot on board. As a Senior GNC Engineer you will own the GNC architecture. You will decide how the aircraft is controlled, how it estimates its state, how it behaves when sensors or actuators fail, and what evidence is needed before each new part of the envelope is flown. You will do a large share of the design work yourself and set the technical bar for the engineers around you. Responsibilities Own the GNC architecture, including control law structure, navigation solution, guidance modes, and redundancy management Design flight control laws for all phases of flight, including takeoff, landing, and failure cases Design the navigation and state estimation solution, including sensor selection criteria with avionics Define the control response to sensor, actuator, and engine failures, and to loss of link Set stability margin and performance requirements and show that the design meets them across the envelope Own the fidelity of the 6-DOF simulation and its validation against flight data Define GNC requirements and interfaces with flight software, avionics, and flight sciences Define the verification approach across simulation, hardware-in-the-loop, and flight test Lead GNC flight clearance for envelope expansion and support flight test on site Lead system identification and model updates from flight data Support system safety assessments and certification evidence for the flight control system Lead design reviews and mentor other GNC engineers Required Qualifications B.S. in aerospace engineering, mechanical engineering, electrical engineering, or a related field, or equivalent experience 5+ years designing guidance, navigation, or control systems for aircraft, spacecraft, or comparable vehicles Owned the GNC design for a vehicle or major flight phase from requirements through flight Algorithms you designed have flown on a real vehicle Supported a flight test campaign, including flight clearance and post-flight model correlation Designed control or navigation behavior for sensor or actuator failures Led design reviews and set technical direction for other engineers Preferred Qualifications GNC experience on fixed-wing uncrewed aircraft Experience with autonomous takeoff and landing Experience designing redundancy management for flight control sensors and actuators Experience building a simulation environment from the ground up Experience with model-based development and autocode under DO-178C and DO-331 Experience with flight control system certification or military airworthiness M.S. or Ph.D. in controls, dynamics, or a related field Why this role There is no pilot to fall back on. The GNC system flies the aircraft from takeoff to landing, and you will decide how it does that, at a stage where the architecture is still yours to set. You will see your design fly on an aircraft that carries two tons. What you get from us Competitive salary and meaningful early-stage equity Relocation support if applicable Employee Health Benefit Plans 6% Retirement matching Flexible PTO Free lunches, snacks, and a stocked fridge at our offices AI tools and subscriptions #J-18808-Ljbffr Hardware FYI