Optimizing Fire Control in Naval Weapon Systems

1. Fire Control Naval Weapons Systems

2. How the target is detected, How the target is tracked, How the weapon is launched, How the weapon is propelled, How the weapon finds the target, How the weapon knows when to detonate, How the weapon detonates. What is missing????? We Know:

3. What is Fire Control How must a weapon be fired at a stationary or moving target from a launcher that is stationary or moving in order to hit the target?

4. The Fire Control Problem • Determining the target position • Target motion • Weapon path that intercepts the target

5. The Fire Control Problem Factors affecting the problem: - Effects of relative motion during flight - Effects of physical phenomena (exterior ballistics)

6. Relative Motion • Present target position • Relative velocity • Own ship motion • Target motion • Bearing rate • Speed across line-of-sight • Future target position

7. The apparent motion of an object when viewed from a point. C 20 mph 10 mph B 10 mph A Relative Motion

8. Affects of Target Relative Motion on Range and Bearing Future Position Present Position Bearing Change Ship’s Heading Present Range Range Change Future Range Present Bearing

9. INPUT Launch Platform Sensors Output Navigation Systems (location) Gyrocompass (course) Electromagnetic Log (speed) Dead reckoning Analyzer Depth indicator Target Course Target Speed Target Range Target Bearing Target Position Radar (search and fire control) Sonar Electronic warfare equipment Data Systems (NTDS) Solving the Relative Motion Problem

10. Ballistics Problem • Target Data • Target position from sensors • Target motion (Target Motion Analysis) • Own ship data from ship sensors • Weapon exterior ballistics

11. Exterior Ballistics • Gravity • Drag • Wind • Drift • Coriolis force • Weapon specifics

12. Line of Fire Line of Sight Gravity tends to accelerate objects downward. (The longer the flight time the more the curve) Effects of Gravity

13. Drag is loss of energy of a projectile during flight. Energy is lost through: a. Creation of air waves (function of projectile shape) b. Creation of suction and eddy currents (shape) c. Formation of heat (friction) Drag will change the aim point by changing the speed of the projectile, increasing flight time, increasing curve caused by gravity. Effects of Drag

14. Drift is caused by the rotation of a projectile (rifling). Drift results in a lateral displacement in flight path. Vertical Plane Drift Line of Fire Horizontal Plane Effects of Drift

15. Line of Fire Line of Fire Wind Wind Wind Wind Horizontal Effects Vertical Effects Effects of Wind

16. Caused by the earth’s rotation. Results in apparent right curve in the northern hemisphere, left in southern. 10 mph 20 mph Coriolis Effect

17. Fire Control Problem • Input • Target data • Own ship data • Computations • Relative motion equations • Ballistics equations

18. Fire Control Problem Con’t. • Solutions • Weapons time of flight • Bearing rate • Line of Sight(LOS): The course the weapon must follow to intercept the target • Speed across LOS • Future target position • Launch angles • Launch azimuth • Launch elevation • Weapon positioning orders

19. Step 1 Step 2 Step 3 Last Step The Iterative Process to the Fire Control Solution

20. Line of Sight Present Range Target Elevation Gun Elevation Horizontal Reference Plane A 3-Dimensional Problem

21. Continuously Measure Present Target Position Compute Relative Target Velocity Stabilize Measured Quantities Environmental Inputs Weapons Positioning orders Ballistic Calculations Unstabalized Launch Angles Future Target Position Time of Flight Launch Angles (Stabilized) Relative Motion Calculations Prediction Procedure Solving the Fire Control Problem