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Basic Radar Principals Quiz

30 Questions - Developed by: - Developed on: 2019-11-26 - 1,362 taken

1

Fine range resolution can be obtained simply by

Decreasing the pulse amplitude
Narrowing the pulse width
Increasing the pulse amplitude
Widening the pulse width

2

For range to be unambiguous, the echoes from the most distant detectable targets must be

Second-time-around-echoes
Third-time-around-echoes
First-time-around-echoes
Fourth-time-around-echoes

3

Which factor in the radar equation is beyond the control of radar system design?

Radar cross section of the target
Receiving effective area of the antenna
Average radar transmitter power
Transmitting gain of the antenna

4

A ___________ is used to provide pulses of input power to the transmitter

T-R switch
Indicator
Modulator
Synchroniser

5

The mapping of major highways would require in an approximate cell size of _______

400ft
80ft
5ft
40ft

6

The degree to which the radiated power is concentrated into the mainlobe is called

Sidelobe reduction ratio
Antenna directive gain
Antenna gain
Solid angle efficiency

7

Calculate the range of this target with echoes having a round-trip transit time of 35 micro-seconds

5250 m
15250 m
21000 m
10500 m

8

Which of the following is NOT a typical tracking loop of a Single Target Track (STT)?

Velocity tracking loop
Angle tracking loop
Range tracking loop
Height tracking loop

9

Which of the following elements in a Radar System is used to time the transmission of the radar pulses?

Receiver protection device
Duplexer
Synchronizer
Modulator

10

To avoid the possibility of the radar operator locking onto a single target and not realizing that more targets are present until it is too late, which mode should the radar operate in?

Target identification
Raid assessment
Fire control
Search

11

For a stationary target, what is the different between the transmitted and the received reflected signals of a Continuous Wave (CW) Doppler radar?

They have the same frequency
The transmitted signal has a frequency lower than the received signal frequency
The transmitted signal has a frequency higher than the received signal frequency
The transmitted signal is of lower amplitude than the received signal

12

Given peak power is 80kW and mean power is 48W, find the pulse duration if the prf is 300pps

2 micro sec
4 micro sec
3 micro sec
1 micro sec

13

Which of the following is NOT a disadvantage of electronic scanning?

Degraded performance at large scan angles
Less weight and cost
Increased complexity
Low efficiency

14

Which of the following is TRUE about the Digital Signal Processor of an Advanced Multi-mode Doppler Radar?

To provide fine azimuth resolution, the radar transmits coded pulses and the signal processor compresses the received pulses by decoding
To provide a truly pictorial map, the actual filter outputs are stored in the scan window
In ground mapping modes, the ground return is clutter only; so it must be filtered out
To provide fine range resolution, the processor forms a vast number of Doppler filters having extremely narrow pass bands

15

A rectangle whose sides are the range and azimuth resolution distance is a

Square cell
Radar cell
Resolution cell
Rectangle cell

16

Which of the following radar navigation applications uses radar altimeter to measure ground clearance?

Terrain following
Doppler Navigation
Terrain avoidance
Terrain Contour Mapping

17

In the receiver of advance Multi-Mode Doppler Radar, the synchronous detector provides ______ output (s).

One
Three
Four
Two

18

Which of the following factors affect the choice of prf?

Minimum range required
Scanning speed of the antenna
Target range discrimination required
Bandwidth of the receiver

19

_______ gives the radar the ability to separate multiple targets at the same range.

Cross-range resolution
Cross-angle multiplier
Cross-range multiplier
Cross-angle resolution

20

The gain of an antenna is calculated based on the following formula:

Gain = P DIRECTION x P ISOTROPIC
Gain = P ISOTROPIC / P DIRECTION
Gain = P DIRECTION x P DIRECTION
Gain = P DIRECTION / P ISOTROPIC

21

The maximum closing rate is ______.

That of the ground from which sidelobe clutter is received behind the radar
The rate of slowest approaching target
Very nearly equal to the maximum velocity of the aircraft carrying the radar
The rate of most rapidly approaching target

22

What categories of PRF will give ambiguous observed range of all significant targets?
(i) Low
(ii) Medium
(iii) High

I, ii, iii
I and iii only
I and ii only
Ii and iii only

23

The term 'Pulse Duration' used in pulse radar is

The length of time for which the transmitter is switched on the give each pulse
The number of pulses occurring in one second
Also known as the Duty Cycle
Equivalent to Peak Power x Duty Factor

24

In the amplitude comparison monopulse radar, the sum and difference signals are used for

Angle and Range tracking respectively
Angle Tracking only
Range Tracking only
Range and Angle tracking respectively

25

For a radar to receive echoes from a target, target _______________.

Must be constantly moving in the air
Must be within the line of sight
Echo must be weaker than the background noise
Must be out of the line of sight

26

SAR is turned on only ______________ times while performing the representative precision blind bombing run.

Three
One
Two
Four

27

The sidelobes robs from the main lobe's total power radiated, by a substantial amount of ________ percent.

25
75
80
50

28

X band radar would normally operate in the region of ________ Ghz.

2 to 8
10 to 14
6 to 10
8 to 12

29

A milti-mode Doppler radar consisted of _______ processor (s).

Four
One
Two
Three

30

The Pulse Repetition Frequency selected for a particular radar depends upon several factors, Please list them

Sources of external noise, Reflections from unwanted objects and The dimensions of the target
Maximum required range, Scanning speed, Mean power available and Improved definition
Transmitter power, Receiver sensitivity and noise factor and Frequency of operation.

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