radar systems unit, division of c4isr swedish defence ... och... · passive radar, an overview lars...
TRANSCRIPT
Passive Radar, an overview
Lars Ulander, Prof.1Radar Systems Unit, Division of C4ISRSwedish Defence Research Agency (FOI)
1Part-time at Chalmers University of Technology
Contents
• Principles and Terminology• What’s on the market?• Some research results• International cooperation• Conclusions
Bistatic vs. Monostatic radar
• Monostatic radar: Self-contained but sensitive to ECM• Bistatic radar: Receiver is silent, but relies on suitable transmitters
Different types of Passive Radar
• Passive Coherent Location (PCL)• Passive Covert Radar (PCR)• Parasitic Radar• Hitchhiking Radar
Taxonomy
RadarMonostatic Bistatic
Cooperativetransmitter
Non-cooperativetransmitter
Radar signal
Broadcast com signal
Taxonomy
RadarMonostatic Bistatic
Cooperativetransmitter
Non-cooperativetransmitter
Radar signal
Broadcast com signal
Passive Coherent Location (PCL) orPassive Covert Radar (PCR)
Taxonomy
RadarMonostatic Bistatic
Cooperativetransmitter
Non-cooperativetransmitter
Radar signal
Broadcast com signal
Parasitic Radar or Hitchhiking Radar
WWII Parasitic Radar
German Kleine Heidelberg(parasitic radar)
British Chain Home Radar(radar transmitter of opportunity)
f = 20-30 MHz, P = 750 kW
Passive radar: How does it work?
When direct signal is not available, Doppler-onlytracking from multiple receiving stations can be used
Correlationprocessing
Passive radar: Positioning
Positioning based on multiple receiving sites or receiver antenna array
Ambiguous position
Transmitters
• FM Radio 87.5-108 MHz– High power; Wide elevation antenna beam– Disadvantage: Bandwidth depends on program content
• Digital TV 170-230 MHz, 470-694 (790) MHz– High power; Narrower elevation antenna beam– DVB-T standard (OFDM) provides a good signal since
bandwidth is independent on program content• Other possibilities
– Satellite broadcasting, communication signals
Industrial developments
Silent Sentry (1999)
Other examples: AULOS (2011), Airbus Defence and Space (2012)
ERA Silent Guard (2014)
THALES HA-100 (2007)
Typical performance: 100-300 km range
A
FOI research: Passive radar ground imaging
Imaged ground area
High-resolution passive radar imaging of ground by synthetic-aperture radar (SAR) processing
FOI research: Passive SAR trials 2012
• Airborne receiver with digital TV as transmitter• Gotland island, the Baltic Sea (Follingbo TV mast)
FOI research: Passive SAR images of ships
200 400 600 800 1000 1200 1400 1600 1800 2000
200
400
600
800
1000
1200
1400
1600
1800
2000
Size 99m x 14m
Size 190m x 32m
Ships located on eastern side of Gotland (Slite harbour) at 40 km and identified by AIS logs
FOI research: Passive SAR image of Gotland
Resolution: ca 5 m x 20 m (limited by a single DVB-T channel)
Artifacts due to TV transmitter tower at Follingbo
FOI research: International cooperation
• NATO SET-186 (closed 2014)– APRA - Airborne Passive Radar Applications– Poland is lead nation
• NATO SET-207 (on-going since 2014)– Advanced situation-specific modeling, sensing and
vulnerability mitigation using passive radar technology– Germany is lead nation
Conclusions
• Passive radar is emerging technology, withsome production and prototype systems
• The main advantage is that system is passive (silent) and does not transmit signals
• The main disadvantage is that system dependson the availability of suitable transmitters
• Passive SAR for ground surveillance is a new research area, with first successful flight trials in 2012 by FOI. New flights conducted in 2016.