KC12 - Electro-Optics Fundamentals

Question 1

State the main difference between systems that uses RF and EO

Answer 1

RF is…

• Wave-like behaviour
• Uses antenna for propagation
• Usually referred in Frequency Domain
• Uses Radar Resolution Cell.

EO is…

• Particle-like behaviour (mainly detection)
• Uses lenses, mirrors and elements such as microbolometer for - - detecting thermal energy
• Usually reference in wavelength
• Uses Field of View (FOV) for resolution description.

Question 2

List the EO radiation spectral bands and state where they reside in the EM spectrum

Answer 2

The Electro-Optics spectrum consists of Ultraviolet, Visible Light and Infrared radiation. The EO spectrum resides in higher end of the frequency spectrum where the wavelength is smaller

Question 3

Define Emissivity

Answer 3

Emissivity is the measure of an objects ability to emit infrared energy.

Question 4

State the ‘Shiny-dull’ law

Answer 4

The ‘shiny-dull’ law states the more shiny the object the higher emissivity value is given to the object

Question 5

State the relationship between temperature and peak wavelength emitted

Answer 5

According to Wien’s displacement principle as the Temperature increases, peak wavelength decreases

Question 6

State the major effect of the atmosphere on Infra-Red (IR) Frequencies

Answer 6

Absorption has the largest effect on the IR EO spectral band

Question 7

State the major effect of the atmosphere on Ultra Violet (UV) Frequencies

Answer 7

Absorption has the largest effect on the IR EO spectral band

Question 8

List target sources of IR radiation and the bands they radiate in

Answer 8

Source/ Temp/ IR region
- Tail pipe/ 800-1500K/ Band 1
- Jet Plume/ Varies/ Band 2-4
- Hot Skin/ 400K / Band 4
- Aircraft Surface Targets/ 300K / Band 4