2. Guidance, navigation and control
• “...Guidance, navigation and control (abbreviated GNC) is a branch
of engineering dealing with the design of systems to control the
movement of space vehicles...”
• GUIDANCE: establishment of the desired path to follow (current,
i.e. in real-time and future).
• NAVIGATION: establishment of the current and future state.
• CONTROL: actions to match the current state (navigation) with the
foreseen path (guidance)
Definition
8. Definition Navigation
• NAVIGATION is the process to find the present and future position
and orbit of a spacecraft using a series of measurements.
• Step 1: MEASURING Obtaining state vectors (x, y, z, Vx, Vy, Vz,...)
at timely intervals.
• Step 2: DETERMINING Reconstructing the orbit based on a set of
state vectors.
• Step 3: PREDICTING Forecasting the imminent future state vector
Guidance, navigation and control
9. Spacecraft Control
• Minimize the spacecraft propellant mass or overall mass,
hence reducing mission cost.
• Increase the accuracy of the control when tracking or
regulating the plant.
• Increase the agility of the spacecraft maneuvers.
• Facilitate the overall design process of the GNC subsystem,
hence reducing mission cost.
Guidance, navigation and control
13. Interplanetary Vehicles and GNC:
• Fly-by between planets
• Mid-course correction maneuvers
• Optimal pointing of antennae to ground
stations Station.
• keeping in Lagrangian points
Guidance, navigation and control
14. Missions Examples
• High pointing accuracy on attitude stabilization agility on attitude
slew.
Guidance, navigation and control
15. GNC for launchers
• Trajectory optimization of nominal ascent trajectories
• Performance maps of rockets
• Optimization of non-nominal trajectories: missionization
• Nominal Splash down of stages
• Stages fragmentation analysis and splash down locations
Guidance, navigation and control
16. GNC of a Small Rocket
Guidance, navigation and control