WS/EO 5: Weapons Guidance

Question 1

State the two broad categories of guidance.

Answer 1

• Guide onto target (GOT) guidance:
  – Sensor continually observes target up to missile impact.
• Guide onto location in space (GOLIS) guidance:
  – Fixed targets.
  – Tracks to a three dimensional position in space.

Question 2

State the three forms of homing guidance.

Answer 2

• Weapon looks forward & homes onto target.
• Must establish line of sight to target.
• 3 forms:
  – Active homing.
  – Semi-active homing.
  – Passive homing.

Question 3

Describe active homing.

Answer 3

• Weapon has illuminator to beam energy at target.
• Reflected energy detected by receiver in homing head.
• Autonomous or fire-and-forget.

Question 4

Describe semi-active homing.

Answer 4

• Target is illuminated by transmitter outside of missile.
• Seeker uses passive receiver to track reflected energy.
• Radar or laser illuminators most popular used.

Question 5

Describe passive homing.

Answer 5

• Seekers lock on to energy radiated by target.
• Includes;
  – Radar energy,
  – IR energy or,
  – Acoustic noise.

Question 6

Describe beam riding.

Answer 6

• Parent projects accurate beam of energy at target.
• Modern systems are laser beam riders (LBRs).
• Missile uses rearward facing receiver.
• Zigzags or spirals up the beam as weapon corrects.

Question 7

Describe Command Man-in-the Loop

Answer 7

• Weapon transmits seeker info. back to agency via;
  – Datalink or fibre-optic cable.
• Agency views picture & corrects errors back via cable.

Question 8

What are the advantages and disadvantage of Active Homing

Answer 8

Advantages:
– Terminal Accuracy;
* miss distance reduces as weapon approaches.
– Fire-and-forget;
* after launch, launch platform no longer required.

Disadvantages:
– Low Transmitter Power;
* size of the missile limits transmitter power.
– Complex;
* transmitter, receiver & power sources limited by size & weight.
– Countermeasures susceptibility;
* alerts target – defeat by countermeasures.
– Targets in Formation separation;
* receiver needs good angular resolution to discriminate targets

Question 9

What are the advantages and disadvantage of Semi-Active Homing

Answer 9

Advantages:
– Accuracy;
* becomes more accurate as target is approached.
– Longer Range;
* illuminator design not limited by missile size.
– Good EPM; (Electromagnetic Pulse)
* tuned to the illumination frequency - decoying more difficult.

Disadvantages:
– Not fire-and-forget;
* illuminator must illuminate the target until weapon impact.
– Needs extra equipment;
* target illuminator.
– Warning to target;
* target is forewarned by high power transmissions.
– Targets in Formation separation;
* receiver needs good angular resolution to discriminate targets.

Question 10

What are the advantages and disadvantage of Passive Homing

Answer 10

Advantages:
– Accuracy;
* becomes more accurate near target - signal strength will increase.
– Fire-and-forget;
* after launch, launch platform no longer required.
– No warning to target;
* does not alert target.

Disadvantages:
– Target emissions;
* If target stops emitting then seeker cannot function.
– Countermeasures susceptibility;
* broad band receivers susceptible to decoys.
– Targets in Formation separation;
* receiver needs good angular resolution to discriminate targets.

Question 11

what is GOT 2 broad categories:

Answer 11

– Homing systems.
* missile looks forward to terminally guide towards target.

– Command systems.
* missile looks rearwards for commands from guidance agency
* tracking both target & missile.