Guidance and homing

Question 1

what is the difference between guidance and homing

Answer 1

guidance gets the torpedo from firing platform to target area/TUA
- Either guided by the firing platform or autonomous

Homing is when the torpedo uses its own sensors to locate the target and prosecute it

Question 2

What are the benefits and drawbacks of closed loop guidance over open loop guidance?

Answer 2

Open
- Cannot update FCS (point and shoot)
- Low single shot kill probability
- Simple and cheap
- Accurate TMA required
- Very sensitive to target alterations

Closed
- High single shot kill probability
- Complex and expensive
- Susceptible to soft kill/jammers
- Less accurate TMA required
- Less sensitive to target alterations

Question 3

Describe the different options available for guidance link and their advantages and disadvantages

Answer 3

SONAR
- due to speed of signed in water and the corresponding low data rate so is not a suitable medium for guidance control
- Open to jamming corruption, mutual interference oceanographic effect on most importantly contra detection

Wire Guidance
- spear uses a single twisted pear wire guidance link which passes all commands and repeat back using a time sharing protocol
- Limited bandwidth low data rate and can be susceptible to breakages

Optical Fibre Link
- Very high data transfer rate due to high with capability
- Historical problems have been tensile stress and manufacturing quality of the fibre (spearfish upgrade)

Question 4

what in initialisation data is required by guidance weapons?

Answer 4

1. weapon data.
2. Target data.
3. Torpedo spare data.
4. Submarine data.

Question 5

Describe the attributes of passive and active homing and the typical considerations in their use

Answer 5

Active
- Effective against quiet target, accurate
- Target is alerted, two way PL, active countermeasures

Passive
- Target un alerted, one way PL, no reverberation
- Noisy target required, no range or speed data, passive countermeasures, self noise susceptible