Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Electronic Warfare > 2 Electronic Support > Flashcards

2 Electronic Support Flashcards

1
Q

ESM receivers are used for _____ reaction.

A

Real-time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

ES Receivers may be devided into two categories:

A

Threat Warning Receiver (TWR) and;
Reconaissance/Surveillance Receivers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a Threat Warning Receiver (TWR)?

A

Provides threat warning over a preset frequency range in real time. It gives you advanced warning that a threat is present.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

TWR is _____ sensitivity.

A

Low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a Reconnaissance/Surveillance Receiver?

A

Have higher sensitivity and direction finding accuracy to measure more radar parameters. Can be real time or long analysis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Reconnaissance/Surveillance Receivers are _______ sensitivty.

A

High

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the four functions of an Electronic Support system?

A

Reception - radar pusle is intercepted and detected
Measurement - signal parameters are measured
Recognition - compare against library
Display / Report - to operator and CCS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are three domains which ES systems must operate?

A

Signal Domain
Temporal Domain
Spatial Domain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Signal Domain

A

Receiver polarization and frequency must match

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Temporal Domain

A

Receiver must be operating at the same time as the radar system transmits energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Spatial Domain

A

Antennas must be able to receive energy from the direction of the transmission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the performance requirements of ES systems?

A

Frequency coverage
Sensitivity and selectivity
Dynamic range
Bearing and elevation coverage
Quick Analysis Time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

For a receiver to intercept a signal it must _____ and then ______

A

Cover the frequency band

Be tuned to the correct frequency of the transmitter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Sensitivity refers to the ability to ______

A

detect signals in noise (SNR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

A wide bandwidth _____ sensitivity.

A

Reduces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is selectivity?

A

The ability to select a certain range of frequencies and reject all others.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Selectivity is _______ proportional to bandwidth.
A selective receiver is ______ sensitive.

A

Inversely
More

Remember sensitivity is inversely proportional to bandwidth.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

If a receiver is very selective, it has ________ probablity of intercept.

A

Reduced.

Selectivity is the ability to select a certain range of frequencies and reject all others. It will not be able to cover a wide range all at once but it can cover one narrow range very well.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is Dynamic Range?

A

Ability to process very weak and very strong signals equally well.

20
Q

What is Analysis Time?

A

The period of time required for reliable target identification.

21
Q

What are two factors which limit sensitivyt of the receiver?

A

Noise Figure
Noise Bandwidth

22
Q

What is dwell time?

A

After a receiver detects a signal, such as a radar pulse, there is a short period of time during which other pulses will be missed.

23
Q

What is Range Advantage?

A

Ratio of the distance where an ESM receiver can detect a radar to the distance a radar can detect the ESM receiver’s platform.

24
Q

What is Probability of Intercept

A

A qualitative measurement of probability of intercept based on time, frequency, direction

25
Q

How do you calculate the number of sweeps required for a certain POI?

A
26
Q

What are the 4 types of ES Receivers?

A

Direct Detection or Crystal Video
Superheterodyne
Instantaneous Frequency Measurement
Compressive

27
Q

Direct Detection: Crystal Video Receiver

A

Extracts the signal from the carrier wave but removes frequency and phase information. It simply tells you there is a threat.

It has a very wide BW though, giving it a high POI.

28
Q

Direct Detection: Scanning Crystal Video Receiver

A

Adds an electronically scanning narrowband microwave filter before the detector.

This provides some frequency measurement by increasing selectivity but it decreases the probability of intercept and it is still low sensitivity.

29
Q

Direct Detection: Multi-Channel Crystal Video Receiver

A

A combination of basic crystal detectors, each tuned to a different band of frequencies.

This allows frequency measurement,

Improved sensitivity because each detector is over a narrower BW.

Imrpoved POI

Faster than the scanning crystal receiver.

30
Q

Superheterodyne Receiver

A

High sensitivity and selectivity
Low POI

31
Q

Superhet: Automatic Tuning Superhet Receiver

A

automatically variable local oscillator frequency. So the LO will automatically sweep over a range of IFs. The conventional will require an operator to change the IF.

Results in very high sensitivity.

Higher POI over conventional superhet.

32
Q

Superhet: Channelized Superhet Receiver

A

One LO and a number of IF amplifiers that together covera wide bandwidth.

Improved sensitivity, POI,

33
Q

Instantaneous Frequency Measurement (IFM) Receiver

A

A bank of frequency discriminators. Each discriminator in series makes progressively more precise measurements.

You can create a parallel array of these discriminators and sum them together progressively more precise to create a digital IFM system.

34
Q

What are the limitations of IFM?

A

Processing time

Low sensitivity
High POI

35
Q

Compressive Receiver

A

Uses an automatic tuning superheterodyne receiver to sweep frequencies with the LO. The signals are multiplied with a delay filter which delays the signal proportional to its frequency. This time delay then corresponds to a frequency. Its another way of differentiating multiple frequency signals without a FFT.

High POI
High sensitivity
Multiple simultaneous signal handling
Good frequency resolution

36
Q

Phase Comparison Array

A

Measures the phase difference to determine direction

37
Q

Simultaneous Amplitude Comparison

A

Compares relative amplitude from different directions to determine strongest direction. This is used because at radar frequencies, you cannot use Adcock array.

38
Q

Steerable Direction Antenna

A

Rotating antenna which indicates its bearing info when the return is strongest. Low POI

39
Q

Four basic actions of recognition

A

Pulse Sorting
PRI Analysis
Scan Analysis
Emitter Comparison

40
Q

What is Pulse Sorting?

A

Determining which incoming pulse is which.

41
Q

How do we describe a signal when Pulse Sorting?

A

AOA
Frequency
Duration
TOA
Amplitude

Each pulse is represetned as 80 to 100 bit description

42
Q

What are 3 methods of direction finding?

A

Time Difference of Arrival
Angle of Arrival
Frequency DIfference of Arrival (doppler)

43
Q

Define Quick Analysis Time

A

The ability of an ESM system to process and analyze EM signals to extract useful information about targets.

44
Q

What is a threat library? What is it used for? How is it generated?

A

Threat library is a collection of information used to identify and classify targets based on their EM emissions.

Information is gathered and analyzed and added to the threat libary for future deployements.

45
Q

What factors affect receiver sensitivity

A
46
Q

Draw a superheterodyne receiver

A

Electronic Warfare (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions