Radar Part 2

Question 1

How do polarised lens work?

Answer 1

Reflects undesired electromagnetic lightwaves

Often called ‘glare’

Question 2

What is polarisation?

Answer 2

Locus of the electric field vector in an EM plane, perpendicular to the direction of propogation (travel to eye or sensor)

Question 3

Polarisation

Image radars can…

Answer 3

Transmit and recieve horizontal or vertical polarisations

Question 4

What are the four combinations of transmit and recieve polarisations?

Answer 4

HH (co)
VV (co)
HV (cross)
VH (cross)

Question 5

Radar systems may be…

Answer 5

Single Polarised (HH or VV)
Dual Polarised (HH and HV, VV and VH, HH and VV)
Fully Polarised (HH, VV, HV, VH)

Question 6

Which type of scattering by polarisation does this refer to?

The appearance of darkness in SAR image in both cross and co polarisation

Answer 6

Specular scattering

Question 7

Which type of scattering by polarisation does this refer to?

The rougher the surface, the higher the co polrisation backscatter

Answer 7

Diffuse scattering

Question 8

Which type of scattering by polarisation does this refer to?

This scattering type only occurs at co-polarisation

Answer 8

Double-bounce scattering

Question 9

Which type of scattering by polarisation does this refer to?
Because it is random, there is equal backscattering in co and cross polarisation

Answer 9

Volume scattering

Question 10

What is backscattering?

Answer 10

The scattering of radiation or particles in a direction opposite to that of the incident radiation due to reflection from particles of the medium traversed

Question 11

SAR Image records what two pieces of information of backscattered signals

Answer 11

Intensity
Phase: depends on the distance the wave has travelled