27 - Terminal Guidance, Fuzing, Explosive train

Question 1

Probability of Mission Kill (P_k)

Answer 1

Probability of achieving Desired Effect per engagement

Question 2

Probability of Hit (P_hit)

Answer 2

Probability of hitting Aim Point per shot

Question 3

Probability of Kill per Hit (P_k|hit)

Answer 3

For each round that reaches the Aim Point, the probability that the Desired Effect is achieved.

Question 4

Number of Hits (N_hits)

Answer 4

Total number of rounds to reach the Aim Point per engagement

Question 5

In order to achieve Desired Effect…

Answer 5

• The round must reach the Aim Point
  and
• The round must then achieve Desired Effect (P_k|hit

Question 6

Definition of Fuze

Answer 6

A device with explosive components designed to initiate a main charge

Question 7

Definition of Fuse

Answer 7

Cord or tube for the transmission of flame or explosion

Question 8

Purposes of a Fuze

Answer 8

1. Keep weapon safe when not needed
2. Detect target
3. Arm weapon
4. Initiate warhead detonation
5. Determine direction of detonation (special fuzes only)

Question 9

Components of a Fuze

Answer 9

1. Safing and Arming (S&A) Device
2. Detonator
3. Target Detection

Question 10

What is the Safing & Arming Device?

Answer 10

• Prevents unintentional warhead detonation
• Physically isolates detonator from the high explosive train
• Arming deactivates the safety feature

Design = Avoid accident conditions

Question 11

Target detection categories

Answer 11

1. Impact or Contact
2. Ambient
3. Timer/Command
4. Proximity = Target detection Device

Question 12

Ambient fuze types

Answer 12

Senses change in environment
- Hydrostatic Pressure
- Air pressure

Question 13

Proximity types

Answer 13

Actuated by some target influence
- Electromagnetic
- EO
- Acoustic/Seismic
- Hydrostatic
- Magnetostatic
- Combination

Question 14

Fundamental Problems of Warheads

Answer 14

• Functional Reliability
• Safety Reliability

Question 15

What is Functional Reliability?

Answer 15

Detonation at the proper time; The fuze properly functions to detect the desired point, arm, and detonate

Increasing # of like components in parallel will increase functional reliability

If A fails, then another path is found

Used in Detonators and Target Sensors

Question 16

What is Safety Reliability?

Answer 16

Prevent unintentional arming; The fuze prevents improper detonation except at the desired point

Increasing # of components in series will increase safety reliability

If A fails, then B doesn’t happen

Used with Safing & Arming devices;