Cranfield University Alumni Event and

Defence Education Conference

«Integrated Air Defence

Systems - Countering Low

Observable Airborne Threats»

JUNE 2017

World War I

Battle of Britain

Dogfight over Britain

Scramble

Battle of Britain

Radar System

Observer Corps

Battle of Britain

Air Chief Marshal

Dowding

Battle of Britain

Integrated Air Defense System

Sensors

(Inputs)Control

Effectors

Integrated Air Defence System

Kill Chain

Detection

(Sensors)

Identification

(Sensor or Procedures Based)

Reaction Selection

(Rules of Engagement)

Selection of Weapon System

Engagement

Assessment

Tracking

Weapons Release

Integrated Air Defence System

Layered StructureNetworked Operation

Tracking Required for EngagementCentralized Command and Control

Technologies affecting IADS Performance

Low Observability Aircraft - Stealth Network Centered Warfare

Low Observability Aircraft – Stealth

A-6 Intruder Stealth Signature

Low

Observability

Aircraft –

Stealth

Low Observability Aircraft – Stealth

Low Observability Aircraft – Stealth

Estimated RCS for the F-35Aircraft, front sector(-45° to +45° in azimuth, -15°to +15° in elevation): 0.01 m²(with RAM)Using the POFACETS code

Reminder:0.0015 m² is the RCS value “leaked” by USAF

Operational Aspects

Low Observability Aircraft – Stealth

Operational Aspects

“First Shot” Advantage

Low Observability Aircraft – Stealth

Operational Aspects

“First Shot” Advantage

Weapons

Effective Range

(i.e 25 Miles)

Radar Weapons Quality

Track Range

Low Observability Aircraft – Stealth

Operational Aspects

“First Shot” Advantage

Data

Link

Low Observability Aircraft – Stealth

Operational Aspects

Integrated Air Defence System - STEALTH

Kill Probability

Engagement (Air/Ground

Based)

Detection Early Warning

Tracking

Tactics

Weapons

Weapon Effectiveness

Integrated Air Defence System - STEALTH

Eliminating Stealth Advantage

• Restore Early Warning Capability

• Ensure maximum weapon guidance capability

(Both Air Based and Ground Based)

• Exploitation of spectrum

Maximization of Information Flow

Countering Stealth Technology

VHF Radars

• 1-3 meters wavelegth – High RCS

• Very large Antennas

• Big Resolution Cell (Low Accuracy)

Reflections from wings – tail

Resonance Scatter

Low Scattering from shaping

features

Low effectiveness of RAM

Low Frequency Radars

Countering Stealth TechnologyLow Frequency Radars

Countering Stealth Technology

NEBO SVU System

MEADS

Low Frequency Radars

• Bistatic

• Multistatic (MIMO)

Countering Stealth Technology

Multistatic and Passive Radars

• Passive

Countering Stealth Technology

Multistatic and Passive Radars

Passive Radar

Principles of Operation

Countering Stealth Technology

Passive Radar

Advantages & Disadvantages

Advantages

• Lack of emission

• Undetectable

• Difficult to jam

• Emplacement without restrictions – no

licensing needs for operation (crucial

in radiation crowded places)

• Anti-stealth capability

• Different frequency bands usage than

conventional systems

• Possible better S/N due to distance

• Multistatic RCS

• Low construction and operation cost (no

transmitter)

Disadvantages

• Increased complexity

• High dependence on space geometry

• Dependence on uncooperative source

• Unpredictable source signal

• Emplacement & coverage restrictions

• Source emission power

• Bandwidth

• Limited detection altitude, due to lack of

exploitable emissions in high altitudes

Countering Stealth Technology

Specular Reflection

Unknown Aspect Angle

Forward Scattering

Theoretical Operation

Antennas Emplacement

DSI

Theoretical Operation

Target Position Calculation

Theoretical Operation

Target Position Calculation

Theoretical Operation

Target Position Calculation 2α: constant distances summary

2γ: focal points distance (= γ1)

Theoretical Operation

Target Position Calculation

Theoretical Operation

Target Position Calculation

Theoretical Operation

Target Velocity Calculation

Implementation of a Passive System

• RTL2832U

RTL2832U → 10,37 €

USB data connection

LNA

Results

Testing - Measurements - EvaluationTarget distance estimation capability assessment

Capabilities of Implemented System

• Range resolution 2000-2500 m

• Velocity resolution 0.50673 mach

• Noise tolerance

• SNR = 5 ∙ 10-5 = -43.0103 dB (with velocity calculation)

• SNR = 10-6 = -60 dB (without velocity calculation)

Research Systems

• NetRad by University College London

Commercial Systems

• Silent Sentry (LM Aero) • Homeland Alerter (THALES)

• AIRBUS DEFENCE • Silent Guard – Era (Chech Republic)

AESA RADARS

Independent Elements for transmittion and reception. Lobe forming by

changing the phase of the antenna elements

Electronic Scanning

AESA RADARS

Almost iminent lobe location (especially usefull in combined modes like

Track while Scan

Increased reliability (no mechanical parts)

AESA RADARS

Main disadvantage the reduction of Antenna Gain (and the range of the radar)

while scanning off boresight

AESA RADARS

44

Off boresight

Angle

AESA RADARS

Countering Stealth TechnologyInfraRed Search & Track (IRST)

Infrared Bands

Windows

Countering Stealth TechnologyInfraRed Search & Track (IRST)

Aerodynamic heating

Countering Stealth TechnologyInfraRed Search & Track (IRST)

Wavelength (microns)

AZIMUTH ANGLE

(DEGREES OF NOSE)

180°

0°

30°

60°

90°

120°

150°

2.4 2.8 3.2 3.6 4.0 4.4 4.8 5.0

100

80

60

40

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40

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100

80

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Rafale OSF: IRST, FLIR, TV, Laser.

Eurofighter PIRATE: IRST, FLIR.

Gripen Skyward: IRST

Countering Stealth TechnologyInfraRed Search & Track (IRST)

F-35 electro-optical systems

AN/AAQ-40 EOTS

AN/AAQ-37 EODAS

Countering Stealth TechnologyInfraRed Search & Track (IRST)

Su-27ULB with OLS-27

PAK-FA IRSTSU-35 IRST

Countering Stealth TechnologyInfraRed Search & Track (IRST)

Range Estimation

Detection Probability

Sensor Model (PIRATE)

Array size, optics Sensitivity Different Modes

Background Radiation

Sky Radiation clouds

Atmosphere

Absorption/scattering/

RefractionBeer’s Law

F-35 Data

Engine Emissions 3D CAD Model

E=exp(-a·R)

Simulation Results

• Excellent Performance in Drought or Clean Atmosphere

• Moderate Performance in Rain or Haze

• Detection – Tracking – Threats Warning Receiver

• Passive Sensor

• Integrated Combat System (IRST, RADAR, EWS)

Conclusions

Conclusions

Improve

Detection

• VHF Radars

• Passive Radars

• OTH Radars (?)

• ……..

Improve Engagement

• Weapon range based

• Tracking

• Sensor Fusion (IRST, Radar)

• Situation Awareness (Network Centric)

Improve Kill Probability

• Tactics

Thank you!