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Senior GNC Engineer (Navigation)

Rio Rancho, New Mexico, United States
Full Time On-site

Summary

Job Description

We are seeking a Senior GNC Engineer to develop advanced navigation solutions for Castelion's long-range hypersonic strike vehicles. This role is critical to enabling precise state estimation across all mission phases, including GPS-denied environments. You will work hands-on with multidisciplinary engineering teams to design, analyze, implement, and validate multi-sensor navigation algorithms, including star tracker-based alternative navigation and sensor fusion architectures, in a fast-paced, hardware-driven environment.

Responsibilities

  • Design and develop navigation algorithms for high-speed flight vehicles, including inertial navigation and alternative navigation (alt-nav) methods
  • Develop and implement multi-sensor fusion architectures using Extended Kalman Filters (EKF) and related estimation techniques
  • Integrate data from IMUs, star trackers, GNSS (when available), and other onboard sensors to provide robust, high-accuracy state estimation
  • Work closely with avionics, flight sciences, and flight software teams to integrate navigation algorithms into real-time embedded systems
  • Conduct modeling, simulation, and analysis to evaluate navigation performance, error growth, and robustness under GPS-denied and degraded conditions
  • Support hardware-in-the-loop (HIL) testing, flight testing, and post-flight analysis, translating results into system-level improvements
  • Characterize sensor performance, biases, and error sources to inform filter design and tuning
  • Develop tools and frameworks for navigation algorithm development, verification, and validation
  • Mentor junior engineers and contribute to best practices in navigation and estimation
  • Partner closely with program leadership to make technical trades aligned with mission success

Basic Qualifications

  • Bachelor's, Master's, or PhD in Aerospace Engineering, Electrical Engineering, or related field
  • 5+ years of experience in navigation algorithm development, analysis, and validation for aerospace or high-performance dynamic systems
  • Strong background in estimation theory, including Extended Kalman Filters (EKF) and multi-sensor fusion
  • Experience with inertial navigation systems (INS) and integration with external aiding sources (e.g., GNSS, star trackers, or similar sensors)
  • Familiarity with alternative navigation (alt-nav) techniques for GPS-denied environments
  • Proficiency in modeling and simulation tools such as MATLAB/Simulink or equivalent
  • Experience with 3DOF and 6DOF simulation environments and real-time implementation of navigation algorithms
  • Strong understanding of sensor error modeling (IMUs, star trackers, etc.) and calibration techniques
  • Familiarity with flight software integration and real-time embedded systems
  • Strong problem-solving mindset, thriving in a fast-paced, hardware-rich, high flight cadence environment

Other Duties

Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities and activities may change at any time with or without notice.

Benefits And Perks

All full-time employees are granted meaningful long-term equity, sharing in the company's significant growth trajectory. We offer four (4) weeks of paid time off, ten (10) company-paid holidays, and comprehensive health benefits - including 100% employee-covered medical and strong dependent coverage, along with dental and vision plans. We also provide paid parental leave to support growing families, a $100 monthly fitness stipend to promote health and performance, and onsite EV charging for convenience. In addition, employees enjoy perks like catered meals, company-covered food during high-demand periods, and a fully stocked kitchen to stay fueled throughout the day.

While this position does not currently require a U.S government-issued security clearance, it may in the near future. Therefore, the ability to obtain and maintain a U.S. government–issued security clearance is required. U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance.

Affirmative Action/EEO Statement

About Castelion

Castelion

Castelion is one of the fastest-rising defense technology companies focused on building affordable, rapidly deployable hypersonic strike systems for the U.S. military. Founded by former SpaceX leaders, the company is working to modernize how advanced weapons are developed and manufactured—using rapid iteration, vertical integration, and scalable production to deliver next-generation deterrence capabilities faster than traditional defense programs. Castelion’s mission centers on restoring America’s ability to field advanced military technology at speed and scale.

For job seekers, Castelion offers the opportunity to work directly on some of the most advanced technologies in national defense, including propulsion systems, avionics, flight software, guidance and navigation, missile systems, and advanced manufacturing. The company hires across aerospace engineering, embedded software, manufacturing, test engineering, avionics, cybersecurity, and operations—making it especially attractive to engineers, builders, veterans, and mission-driven professionals who want hands-on ownership of real hardware.

Unlike traditional defense contractors, Castelion operates with a startup-style engineering culture modeled after rapid aerospace development environments. Employees work closely with flight hardware, testing, and production systems in a fast-paced setting where speed, accountability, and execution are prioritized. The company openly emphasizes a builder mentality—giving team members the chance to own major projects and contribute directly to systems with national security impact.

As the U.S. military increases investment in hypersonic weapons, missile modernization, and scalable deterrence capabilities, Castelion continues to grow rapidly through major government contracts and manufacturing expansion. For professionals seeking a high-growth aerospace and defense company where they can help shape the future of national security technology, Castelion is quickly becoming one of the most exciting employers in the defense innovation ecosystem.

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