KC13 - Electro-Optic (EO) Seekers

Question 1

Describe the operation and features of the following EO seeker types: Spin Scan Reticle

Answer 1

This particular missile tends to have a corkscrew effect during its flight path to the target

Similar in operation as previous but magnitude error is resolved (high or low)

Either AM or FM modulation changes relative range and position respectively

Example shows Frequency Modulation:
Red Target - Low Frequency

Green Target - High Frequency

Both relative to boresight reticle for high or low position, a null response for boresight on target

Question 2

Describe the operation and features of the following EO seeker types: Conical Scan Reticle

Answer 2

Advantage - no signal loss when target is on boresight

The reticle remains stationary while the target image is scanned around the reticle in a circular motion using a pivoted mirror

Question 3

Describe the operation and features of the following EO seeker types: Rosette Scan

Answer 3

Advantages:

High on boresight accuracy - smaller FOV and high revisit rates
Can resolve and discriminate multiple targets:
Cloud - wide pulse width
Target - medium pulse width
Flare - short pulse width

Disadvantages:

A very complex processing system requiring many overlays to achieve 2D image

Question 4

Describe the operation and features of the following EO seeker types: Pulse Position

Answer 4

Advantages:
Smaller instantaneous Field of View (FOV)
Smaller background signal
Can use different detector materials
Allows rejection of decoys / noise

Question 5

Describe the operation and features of the following EO seeker types: Imaging

Answer 5

Imaging systems build up an image via:
Raster scan pattern - single detector scans the FOV in a raster pattern and ‘remembers’ what was detected.

Line scan pattern - uses multiple detectors that scan the entire FOV in one sweep. Faster image updates than raster scan

2D Imaging