Simulation of the flight of a short range air defense system rocket before radar acquisition

This report deals with the problem of digitally simulating the motion of a Short Range Air Defense System (SHORADS) rocket during launch and until the rocket has been acquired by a launcher-fixed tracking radar. Physical and mathematical models of the launcher, the rocket per se and its environment, the rocket's control system and the pre-radar-acquisition guidance system are presented. The pre-acquisition guidance sensor is a dual field of view infrared angle sensor. The rocket is of the folding-wing, tube-launched, boost-sustain type and rolls at an essentially constant rate. Control torques are generated by deflecting the thrust of the solid-propellant, sustainer rocket motor and are available about a single rocket-fixed axis. The models for the launcher and rocket include the anomalistic effects of tipoff, launcher slew rate, rocket dynamic unbalance and thrust misalignment, aerodynamic forces and moments, jet damping, variable mass, and moments of inertia of the rocket and winds. Two computer codes one for the launch phase and one for the post-launch, controlled phase - are also described and typical simulation results are presented and discussed. The rocket simulated performs well when various combinations of anomalies are present, but large slew rates of the launcher result in failure of the rocket to enter the field of view of the infrared sensor, if it is launched from a lagging tube.