Notes On Missile Guidance

NOTES ON MISSILE GUIDANCE (Frame the following points into meaningful paragraphs while writing as an answer!) What is guidance? • Guidance is the means by which a missile steers or is steered to a target. • The type of guidance is also dependent on the motor, warhead and threat. • More specifically, the type of guidance chosen is dependent on the overall weapon system in which the missile will be used, on the type of threat the missile will be used against, the characteristics of the threat target, and other factors.

Figure. Basic Form of guidance Basic factors affecting the missile design • • • •

Threat Operating environment Cost State of the art – Since the last three is normally known, the missile design centers on meeting the threat in the environment with the state of the art, at minimum cost.

Types of missile motors: (i) All Boost • It typically will make the missile accelerate rapidly, causing high peak velocities. However, this causes high missile drag, high aerodynamic heating, and short time of flight, for a given range • This is suitable for a rear hemisphere, tail chase encounter. (ii) All Sustain • It has low acceleration, resulting in lower aerodynamic drag and longer time of flight, for a given range. • It can be used in a look up engagement, and to provide sufficient velocity for maneuvering at high altitude. • The motor is suitable for head on engagements, or in look-up engagements at high altitudes

(iii) Boost Sustain • The boost sustain motor represents an attempt to combine the best features of the all-boost and all-sustain designs.

Figure. Types of missile motors The Missile Guidance system model • Guidance is the means by which a missile steers, or is steered, to a target. • A guided missile is guided according to a certain guidance law. • The inputs are target location and missile to target separation. • The desired output is that the missile have the same location as the target

General Problems of Guidance System Design 1. Help to maximize the single shot kill probability (SSKP) by minimizing the miss distance 2. Sources of miss distance • Initial heading error • Acceleration bias • Gyro drifts (if gyros are used in seeker stabilisation) • Glint (scintillation noise) • Receiver noise • Fading noise

• Angle noise (due to varying refraction with frequency diversity) 3. Preserve stability of the parasitic attitude loop 4. Filtering • Limit power consumption and saturation of the actuators • Prevent noise from excessive hitting of dynamic range limits, such as auto pilot g limits