Comparative autopilot study: SFI, LQR, and MPC guidance laws evaluated against missile longitudinal dynamics. Fastest time-to-target confirmed at 8 seconds. Built in MATLAB with CasADi/IPOPT.
Objective: evaluate three autonomous guidance laws against a linear short-period missile model. Each controller is assessed on trajectory accuracy, control effort, and time-to-target. Simulations executed in MATLAB; MPC solved online with CasADi and IPOPT for every timestep across a 50-step engagement.
The missile dynamics model is based on Mracek & Ridgely's short-period approximation — a two-state system (angle of attack α, pitch rate q) driven by fin deflection δp. Both controllability and observability confirmed analytically before controller synthesis.
The MPC problem is solved fresh at every timestep over a horizon of N=10 steps. The CasADi symbolic model uses discretised longitudinal dynamics, minimising tracking cost plus control effort while enforcing actuator bounds throughout the horizon.
A soft terminal constraint steers the predicted 3D position toward the impact point [10500m, 300m] — giving the controller spatial awareness beyond the immediate tracking objective.
| Metric | SFI — Eagle | LQR — Talon | MPC — Viper |
|---|---|---|---|
| Time to Target (s) | 13.80 | 10.00 | 8.00 ✓ |
| Avg Control Effort (rad) | 0.04 | 0.10 | 0.08 |
| Final Az Error (g) | 19.91 | 0.00 ✓ | 14.97 |
| Total Control Effort Σ|u| | 48.94 | 10.34 | 6.06 ✓ |
✓ = best in category · MPC: fastest engagement and lowest total effort · LQR: perfect steady-state accuracy