Use of Surveillance systems

Question 1

Why is beam width important with respect to target display

Answer 1

The width of the beam determines how capable the radar is of resolving bearing between individual targets. If the beam is too wide it wont be able to differentiate between two targets close together

Question 2

What causes fade areas in radar coverage?

Answer 2

These may exist where there are gaps in the radar coverage. They may also result from shadowing by hills or obstructions in the line of sight between a particular target and the radar aerial.

Question 3

Describe “radar overhead” and how it affects radar coverage.

Answer 3

This is a blind area that exists overhead the radar site. The size of the radar overhead is a function of aerial design and the amount of “tilt” given to the aerial in relation to the horizontal. The higher the aircraft is the longer the aircraft will be in the “overhead”.

Question 4

How are problems with radar overhead and fade areas normally resolved in an ATS radar system?

Answer 4

The problems with the radar overhead and shadow areas can solved by using two or more radar sites to cover a particular area.

Question 5

What are the two main variables that determine whether an aircraft can be detected by a radar system?

Answer 5

Altitude and distance from aerial

Question 6

If an aircraft is at 3000ft how far away from the aerial would you expect to see it

Answer 6

30NM

Question 7

The ability of a particular radar to be able to detect an aircraft will depend on factors such as:

Answer 7

The power of the transmitter
The location of the aerial and
The height and reflective properties of the aircraft.

Question 8

What is radar clutter?

Answer 8

Any returns received from other targets, such as rain, birds or the ground, that clutter the display and make it difficult to distinguish the aircraft

Question 9

How are gaps in radar coverage overcome

Answer 9

By having overlapping coverage from another radar site

Question 10

What two planes does a radar operate in?

Answer 10

Horizontal (azimuth) and vertical (elevation)

Question 11

What issues are associated with having the beam width of a radar too narrow?

Answer 11

if the beam width is too narrow then the reflected energy detected by the receiver will be weak and so will be the displayed returns.