1. Fire Control Naval Weapons Systems

2. We Know: 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?????

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

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

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

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 GravityDragWindDrift Coriolis force Weapon specifics

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

13. Effects of Drag 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.

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

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

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

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

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

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