High maneuverability of guided projectiles enables engagement of fleeing targets, opens the area of influence of a weapon system, and allows new missions to be performed such as prosecuting targets in defilade. Gun-launched precision munitions have unique constraints that create technical barriers to achieving enhanced maneuverability. Structural integrity during the gun launch event, packaging control surfaces within the launch tube, and affordability are paramount concerns. The present work is a fundamental investigation of the flight mechanics and guidance, navigation, and control technologies necessary to optimize maneuverability of affordable precision projectiles. Detailed aerodynamic modeling and nonlinear equations of motion for the flight of a fin-stabilized airframe meeting low control authority constraints were implemented in simulation. Flight control laws were developed for various maneuver schemes with different actuator realizations. Simulations were conducted over a large parameter space to evaluate maneuverability. Results provide the optimal parameters within the distinctive scope of gun-launched munitions. Flying a skid-to-turn airframe with four canards in the "X" configuration maximizes control authority with moderate volume allocation and actuator bandwidth requirements. Examination of dynamic stability along with static stability illustrates that high-fidelity aerodynamic characterizations are required when optimizing maneuverability due to the implications on the airframe design and flight control algorithm development. NomenclatureD = diameter S = reference area m = mass t a I I I , ,  = moment of inertia tensor, axial moment of inertia, transverse moment of inertia V = total velocity of projectile Q = dynamic pressure M = Mach number    , , = pitch, yaw, total angle-of-attack Z Y X , , = forces acting on projectile N M L , , = moments acting on projectile X C = axial force coefficient N C = normal force coefficient 0 l C = static roll moment coefficient p l C = roll damping coefficient m C = pitching moment coefficient q m C = pitch damping coefficient

A state estimation method for gun-launched precision projectiles using affordable technologies is presented. Navigation algorithms were developed to incorporate flight dynamic models with measurements from inertial sensors and, if available, GPS.GPS is used to estimate an inertial sensor bias which can then be used if GPS is lost later in flight. This novel technique allows GPS to continue to benefit the flight after it is unavailable and allows noisy, low cost sensors to provide a useful state estimate.Simulations were conducted to assess algorithm performance over a range of conditions. These results indicated that the algorithm with only 10 seconds of GPS availability yields a position error of less than 35 m over a 30 s flight. This effort shows that navigation error using coupled GPS/INS is sufficient to increase system accuracy for munitions even if GPS should become unavailable during flight.

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