Ew

Question 1

State the four stages of the ES Process

Answer 1

Search
Intercept
Identify
Locate

Question 2

State the four receiver groups of a conventional system

Answer 2

RWR
LWR
MAWS
ESM system

Question 3

Describe antenna

Answer 3

Provides gain and directivity

Question 4

Describe receivers

Answer 4

A device that intercepts transmitted electromagnetic energy

Question 5

Describe signal processors

Answer 5

De-Interleave signals
Process signals
Obtain LOB

Question 6

Describe emitter library

Answer 6

Produced by EW support units (JEWOSU) and lists all known emitters in the area of operations

Question 7

Describe the heterodyne principal

Answer 7

A high frequency signal and an intermediate signal are mixed to produce a sum and a difference. The sum is disregarded and the difference is used as the new lower frequency signal

Question 8

Describe frequency coverage

Answer 8

The frequency range which the receiver can tune

Question 9

Describe selectivity

Answer 9

Ability of a receiver to discriminate between close but different frequencies

Question 10

Describe dynamic range

Answer 10

The range of amplitudes that a device and process without distortion of the signal

Question 11

Describe sensitivity

Answer 11

The smallest detectable signal power a receiver needs to distinguish it from noise

Question 12

Describe signal to noise ratio

Answer 12

The ratio of signal voltage to noise voltage at receiver

Question 13

Describe fidelity

Answer 13

The accurate reproduction of intelligence

Question 14

Requirement of an ES receiver

Answer 14

Must have wide input bandwidth
Must have fine frequency resolution
Must be highly sensitive
Must have good dynamic range
Must be able to scan in all directions
Must receive all polarity signals
Must have a high POI

Question 15

Describe scanning superheterodyne receiver

Answer 15

Narrow bandwidth receiver swept over a frequency range of interest. Sweep is stopped on detected signals

Question 16

Describe channelised superheterodyne receiver

Answer 16

Receiver divides frequency range to be covered into contiguous channel by filters

Question 17

Describe signal de interleaving

Answer 17

Extraction of signal if interest from a mix of all present signals

Question 18

Parameters measured by ES systems

Answer 18

AOA
RF and Bandwidth
Time of arrival
Pulse amplitude
PRI/PRF
Pulse width
Polarisation
Scan type and scan rate
Intra and inter pulse modulation

Question 19

Describe POI

Answer 19

The sum of all combinations of probable time coincidences of the parametric windows of the target and ES systems

Question 20

Describe POR

Answer 20

POR is the probability that a target signal, once detected, will be processed, correctly identified and presented to the operator within a specific time

Question 21

Factors determining POR

Answer 21

Emitter library needs to ensure inclusion of emitter
Emitter library needs to minimise ambiguity
Processing power in dense signal environments

Question 22

Direction finding techniques

Answer 22

Directional antenna
Amplitude comparison
Phase comparison
Time difference of arrival

Question 23

Describe the function of radar warning receiver

Answer 23

Indicates type, location and threat level of RF energy

Question 24

Describe the stages of missile flight

Answer 24

Launch, boost, coast

Question 25

Describe missile approach warning system

Answer 25

Detects UV radiation when missile is in boost phase. Cannot detect in coast phase IR, pulse Doppler and UV

Question 26

Describe laser warning receiver

Answer 26

Detects the coherent nature of laser light

Question 27

Three sub divisions of electronic attack

Answer 27

Jam, Neutralise, Deceive

Question 28

List the four main EA equipment types

Answer 28

Radar jammers IR jammers CMDS Decoys

Question 29

Describe jamming

Answer 29

The use of mechanical devices or electromagnetic transmissions to interfere with adversary electronic devices, equipment or systems

Question 30

State the two forms of jamming

Answer 30

Electronic jamming Mechanical jamming

Question 31

Describe spot jamming

Answer 31

Continuous jamming of one specific frequency

Question 32

Describe barrage jamming

Answer 32

Transmits noise over a given bandwidth

Question 33

Describe swept spot jamming

Answer 33

Moves a spot frequency of noise across a selected bandwidth

Question 34

Limitations of chaff

Answer 34

May negate noise jamming May alert an unaware enemy Only effective against radar guided missiles Enemy radar characteristics must be known Chaff cloud characteristics must be known for employment Limited effectiveness against advanced radars

Question 35

Define deception jamming

Answer 35

The deliberate radiation, re-radiation, alternation, absorption, or reflection of electromagnetic energy in a manner intended to mislead the enemy in the deception or use of information received by their electronic systems

Question 36

Describe range gate stealing

Answer 36

Exploiting the automatic gain control system by intercepting the pulse and amplifying it as an echo with a time delay

Question 37

Describe velocity gate stealing

Answer 37

Exploiting the automatic gain control system by intercepting the pulse and amplifying it as an echo with a frequency shift

Question 38

Describe flare limitations

Answer 38

Only a limited number can be carried Flare dispensing interval may allow target acquisition Weapons can discriminate between flares and targets Once loaded, flares cannot be changed Flares are not intense enough to protect an aircraft using afterburners

Question 39

Describe neutralisation

Answer 39

The deliberate use of electromagnetic energy to temporarily or permanently damage enemy’s devices which rely exclusively on the electromagnetic spectrum

Question 40

Explain open loose jammers

Answer 40

Directs generic beam at the missile seeker to jam it

Question 41

What are the types of neutralisation jamming

Answer 41

Hot brick Arc plasma DIRCM

Question 42

Describe Closed loop jammers

Answer 42

Bounces laser energy off missile seeker to analyse the type of seeker, then selects modulation most effective for that particular seeker