Exam Flashcards
What is EW?
A military action that exploits electromagnetic energy to provide SA and create effects.
Can provide a commander with means to shape an EM environment in order to support ops (denying the same to adversaries).
State the military uses of the EM spectrum.
Radio (Radio Waves)
Radar (Microwaves)
EO (IR and EO)
Name the 3 sub divisions of EW.
Electronic Attack
Electronic Defence
Electronic Support
(EEESAD)
Name the EW measures used to achieve EA, ED & ES.
Electronic Support Measures
Electronic Counter Measures
Electronic Protective Measures
(PCS)
Define Electronic Attack
Prevent/reduce effective use of the EM spectrum by:
Jamming
Deception
Neutralisation
(Jack Drinks Nothing)
What is Electronic Neutralisation?
Use of EM energy to either
Temporarily
Permanently
Damage enemy devices that rely on the EM spectrum
(SEAD/DEAD)
What is SEAD
Suppression of Enemy Air Defence
What is DEAD
Destruction of Enemy Air Defence
What is Jamming?
Deliberate radiation/re-radiation/reflection of EM energy to impair effectiveness of enemy electronic systems and equipment
What is Deception?
Deliberate radiation/re-radiation/alteration/reflection of EM energy to confuse, distract or seduce an enemy electronic system.
What is ED?
Electronic Defence.
The use of EM energy to provide protection to friendly forces and to enable effective use of EM spectrum.
Name the EW measures to achieve ED
Falls under Electronic Protective Measures (EPM) :
Passive
Active
Emcon
Electronic masking
Describe passive ED protection
Protection from friendly and adversary EW activity.
Planning, training, design of equipment
Describe active ED measures
Achieved through measures such as
Frequency hopping (HavQuick)
Burst transmission
Changing polarisation of radar pulse (plane of wave relative to earth surface)
Describe EMCON
Selective and controlled use of EM, acoustic or other emitters to optimise C2 capabilities
Minimising detection
Describe electronic masking in ED
Controls EM radiation on friendly frequencies, to protect the emission characteristics of comms & electronic systems against an enemies ES.
E.g. Encryption
What is ES?
What is it split into?
Electronic Support.
Monitors use of EM spectrum (actively/passively). Data then provided SA & supports Intel.
Split into:
ESM (Threat warning)
SIGINT
What is SIGINT split into?
Electronic intelligence (ELINT) Comms Intelligence (COMINT)
Name the 3 main ES threat warning systems.
Radar Warning Receiver (RWR)
Missile Warning Receiver (MWR)
Laser Warning Receiver (LWR)
(Rate My Life)
The lower the frequency the…
Larger the antennae
Longer the wavelength
The higher the frequency the..
Smaller the antennae
Shorter the wavelength
What is Radar?
Radio Detection And Ranging.
Process of detecting and locating a contact by means of reflected radio energy (Primary Radar)
What is a Radar Mile?
The time taken for a pulse to travel to a target distance of one mile & return
What is Radar Horizon?
How do we work out Radar Horizon?
How far a Radar can see (no obstructions).
Calculation:
1.23 × ( /Antenna Height)
What is the Radar Cross Section?
What are the factors that affect RCS?
How detectable an object is using radar.
Size Shape Aspect (Side on/ Head on) Material Lumps, bumps, angles, cavities
What are the Pulse Radar Parameters?
A train of pulses is categorised by the number of pulses per second and width of each pulse:
PRF (Frequency)
PRI (Interval)
PW (Width)
What is the Pulse Width?
Length of pulse in Nanoseconds
Also called pulse duration/length
Define minimum detection range
The minimum range to which the receiver cannot receive reflected energy (as it is still sending a pulse).
Affected by the pulse width (balance of power output vs min detection range)
What is target discrimination
Denoted by the pulse width and how much of the waves are bounced back.
Larger pulse widths won’t discriminate between two targets but is higher range (and vice versa).
What is the Pulse Interval?
Time between the start of one pulse to the start of the next pulse
Inversly proportional to PRF
What is the PRF?
Pulse Repetition Frequency
Number of pulses transmitted in one second
Can be called PPS(Pulse Per Second) / Hertz
What is the MUR?
Maximum Unambiguous Range.
The longest range to which a transmitted pulse can travel out and back again between consecutive transmitted pulses
What is the calculation for MUR?
MUR= (1/2 x Speed of Light) / PRF
The software is designed to not count the pulses after a certain time (stops counting outside range scale) in between Pulses
What are the three scan types?
Circular (A)
Antenna is centre, scans around
Sector (B)
Antenna scans in front of aircraft, sweeping motion
Raster (C)
Sweeps up and down to find height
What is the Ariel Rotation Period? (ARP)
The rate at which the scanner must rotate in order to receive all responses out to a certain range before moving azimuth
What are the 3 types of display?
Type A:
Shows range and downrange bearing. Gives indication of range and size of target (if side on to scanner)
Type B:
Gives range and changing bearing (to target, relative to aircraft). Gives in a grid display.
PPI (Plan Position Indicator):
Gives bird eye view of radar
North is top
Usually centred to yourself (can be centred on target)
What is PPI
Plan Position Indicator
Type of radar display (bird eye view)
What are the 5 countermeasures used by systems
Deceptive Jamming Noise Jamming Frequency Agility Chaff Towed Radar Decoy (TRD)
Describe Deceptive Jamming
Transmits exact frequency to search radar ahead of time to deceive the radar (creates false targets)
Noise Jamming
Transmits a noisy picture based on beam width
Can only jam known adversary frequencies
Radar burn through can occur when the adversary radar has more power (overrides the noise)
Describe Frequency agility
Like HavQuick, radars can also hop frequencies
Stops adversaries from Jamming frequencies
Can be used as a ‘de-clutter’ technique
Describe Chaff
Used to create spurious EM signals and deceive missiles and radar.
Different sized strips create different wavelengths, and the chaff blooms to create pockets of spurious signals in the air
Light materials are used to linger (e.g. Fibreglass)
Describe TRD
Towed Radar Decoy
Acts as a decoy for incoming missile systems
Prevents acquisition by giving off larger Radar Cross Section than host aircraft
Needs comprehensive Mission Dependant Data to be effective
Meaning of EW
Any military action that involves the use of the EM spectrum
Name the anatomy of a missile
Motor Fuel 1st stage booster/ Ejector Sensor/ Seeker Head Data-Link Guidance and Control Computer Warhead
Missile engagement process
Search Acquire Track Launch Intercept
Missile Guidance loop
Sensor
Error
Guidance computer
Steering command
Missile Guidance Techniques
Command Guidance (CLOS & COLOS) Beam Riding Homing (Passive) Homing (Semi Active) Homing (Active) Track Via Missile
Name the 4 characteristics of CMD guidance
Not fire & forget
Overt
Susceptible to countermeasures
Signal strength decreases as the missile gets closer to target
4 characteristics of Beam Riding
Not F&F
Overt
Susceptible to tactics
Slightly less strength at target (negligible)
4 characteristics of Passive Homing
F&F
Covert
Susceptible to flares
Strength increases closer to target
4 characteristics of Semi-Active Homing
Not F&F
Overt
Susceptible to CM
Strength increases closer to target
4 characteristics of Active Homing
F&F
Overt
Susceptible to chaff
Strength increases closer to target
4 characteristics of Target Via Missile
Not F&F
Overt
Susceptible to CM
Strength increases closer to target if active, less if CMD
What is MEZ and what Pro word does it use?
Missile Engagement Zone
Trespass
What do we call when an Aircraft encroaches the MEZ?
Callsign
TRESPASS
Location
System
Four components of a radar system?
Frequency
PRF
PW
ARP
What does ARP matched with and what does it affect?
MUR
Data link
What is the ESM advantage?
When we can detect EM energy outside the theoretical MUR of the target radar
What are the principle uses for ESM?
Intercept
Identify
Locate
What three things does the DOA measure?
Time
Amplitude
Phase
On adjacent ariels
15000ft =150nm for radar horizon
