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ContentsSeaborne Passive Radar: An Initial
Investigation
Dr. Francois Maasdorp
Dr. Craig Tong
Christo Cloete
2
Short Bio
• Francois received his B.Eng (electronics) (2001) and M.Eng (cum
laude) (2008) degrees from the University of Pretoria and his PhD
(2015) at the University of Cape Town, South Africa. He was
employed at the University of Pretoria from 2003 to 2005 where
he lectured under graduate courses in Digital Communications and
Linear System Analysis. For the last 12 years, he has been working
within the field of Radar and Electronic Warfare (EW) at the CSIR,
South Africa as a signal analyst and system engineer. His research
interest includes Radar and EW sensor systems, as well as antenna
array and signal processing (particularly in communications EW,
GNSS systems and Passive Radar).
3
Presentation Outline
• Introduction
– Passive radar concept
– Achievements to date
• Seaborne Experiment
– Goals
– Land based experiment
– Sea based experiment
• Future Investigations
• Conclusion
• Acknowledgements
4
Introduction – Passive Radar Concept
5
Introduction
• Current passive radar focus
– FM Broadcasting
– Starting to investigate digital TV (DVB-T2)
• Demonstrated air target detections (FM broadcasting)
– Small aircraft (Cessna) have been detected at 50km
– Large airliners detected > 300 km
• Target feature extraction
– Propeller modulation
• Sea surface vessel detections
– Namacurra
– Detections at 3 - 5km
6
Introduction - FM Radio Coverage
80 km
150 km
7
Introduction – Single Site Tracking
• West Coast, Western Cape, SA (2014)
– Piketberg FM transmitter
• Tracking (2-D)
– C-47TP Dakota
– Range and Angle
8
Introduction – Multi-Static Tracking
• Western Cape, SA (2014)
– Cape Town FM transmitter
• Detection and tracking (2-D)
– Boeing like targets
– Off-line processing
Atlantic Rx
Kalbaskraal Rx
9
Introduction – Detection Range &
Platform recognition
• Gauteng, SA (2013)
– Sentech FM Transmitter
• Target Recognition (towards)
– Accurately estimate the RPM of
a Cessna 172 propeller
10
Introduction – Maritime Target Detections
• MDA Experiment in Saldanha (2014) – Transmitter (Simulated higher BW)
• 1W, FM with 2MHz IBW
• RR 75m
– Detections
• Harbour Patrol Boat (4.5km mono)
• Buoys
11
Introduction – Long term passive radar test
bed development
• 5 receiver nodes
– In Gauteng Region
– Dual baselines at some Rx
• 1 central node at CSIR
– Target tracking
– Database
– Reference data interface
– Web Display
• Connected with high
bandwidth capacity links
– 1/10 Gbps South African Research Network (SANREN)
12
Introduction – Preliminary results (POD, CSIR
& SANSA
13
Seaborne Experiment - Research Scope
• Research Context
– Initial Investigation for using Passive Radar onboard a maritime platform
• Allow for covert operations
• Currently only air-targets are considered
– In support of Project SYNE
• Plan and Execute Trails in False Bay, Cape Town
– Test the effectiveness of FM-based passive radar on a seaborne platform (Namacurra)
– Compared to static, land-based passive radar
performance.
14
Initial Experiment – AFB Waterkloof
• Equipment: (Tx - 94.2MHz)
– 1 x Ref & 1x Surv Antenna
– ComRad3 receiver (NB filter)
– IQ data recording on Laptop, offline processing
15
Initial Experiment – AFB Waterkloof
• Best detection results;
– 135km detection range
16
Simon’s Town Experiment
• 12th – 16th March 2018
• SAN provided Namacurra HPB
• Equipment:
– 1 x Ref & 1x Surv Antenna
– 19 Inch rack mounted PCL Rx• RF receiver (ComRad3)
• GP-GPU Processing Server
– SpatialDual IMU (dual base GNSS antenna)
– 1800W Inverter, • Using on-board batteries
– 2 x Laptops
• 3 Days IQ Data Recordings
17
Simon’s Town Trials – IMU recordings
14/03/2018 15/03/2018
18
Simon’s Town Experiment – Detection Results
19
Simon’s Town Trials – Future
• Current Findings
– Target detections, but at limited ranges
– But, under the worst conditions (Frigate should be more stable)
• Further analysis of FM data
– Characterisation of clutter effects
– Characterisation of multipath effects
– Actual Rx position update
• Using the IMU position data
– Investigate range-Doppler migration algorithms
• For example Keystone, Chirp Z
20
Simon’s Town Trials – Future
• Digital Video Broadcasting
– Higher frequency, smaller antennas
– Higher range resolution• Sea surface detections
• Drones
– Area coverage yet to be done
• Omni-directional Antennas
– Beamforming/Null steering in all directions essential
– COMINT circular array on Frigate may be well suited for this
– Dynamic range considerations
21
Conclusions
• Passive radar may be able to contribute to a covert
situations awareness function in the maritime and
seaborne domain.
• It is shown that FM-based passive radar is able to detect
air targets from a small, harbour patrol vessel.
• There is significant performance degradation of classic
processing techniques due to platform motion.
• Motion compensation and circular arrays are essential to
realising a practical sensor.
• Digital television broadcasts may unlock further capability
such as sea-surface target detection.
22
Acknowledgements
• Lt. Col. J. van Zyl, Lt. Col. A. van Wyk, Capt. S. Badenhorst and CO. B. van
Heerden for assisting and hosting the CSIR at Air Force Base (AFB) Waterkloof for
the land based PCL trials.
• Capt. (SAN) G. Walker and Thomas Mkhaliphi for arranging the availability of the
Namacurra.
• Cdr. R. Strydom and the Naval Electromagnetic Analysis Section (NEMAS) staff
for hosting the CSIR at the SAN Naval base during the week of the sea based PCL
trials.
• Adrian Stevens for making IMT equipment available to the CSIR during the week
of the sea based PCL trials and also for being involved with the logistics of the
CSIR equipment.
• Stephen Paine for making UCT equipment available to the CSIR during the week
of the sea based PCL trials and also for participating in these trials.
• Joshua Sendall (DPSS), for developing and implementing the adaptive range-
Doppler processing techniques under the CSIR thematic passive radar
programme.
Thank you