MS Final Exam Frequency Diversity Wideband Digital Receiver And Signal Processor For Solid-State Dual-Polarimetric Weather Radars Kumar Vijay Mishra Advisor: Dr V. Chandrasekar Committee: Dr A. Jayasumana and Dr P. Mielke Jr. June 15, 2012 Background Photograph by Kumar Vijay Mishra
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MS Final Exam
Frequency Diversity Wideband Digital Receiver And Signal Processor For Solid-State Dual-Polarimetric Weather Radars
Kumar Vijay Mishra
Advisor: Dr V. Chandrasekar
Committee: Dr A. Jayasumana and Dr P. Mielke Jr.
June 15, 2012
Background Photograph by
Kumar Vijay Mishra
MS Final Exam
Outline
• Introduction
• Context of Solid-State Transmitters in Weather Radars
• Existing Weather Radar Digital IF Receivers
• Digital Receiver solution for Solid-State Transmitter
Weather Radars
• Multi-Channel Receiver Design
• Processing Modes
• NASA D3R System
• First Results from Field Deployment
• Summary
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• Weather radar equation (Probert-Jones, 1962)
• Radar observables in terms of backscattering matrix
Duplexer
Duplexer
To H-receiver
To V-receiver
h- port
v- port
H-Transmitter
V-Transmitter
STALO/
COHO
Range R
Δ r = cτ/2
Tx - H
Tx - V
Rx - H
Rx - V Shh Shv
Svv Svh
Shh Shv
Svv Svh
Sinclair Matrix
Signal Theory of Weather Radars
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Context of Solid-state transmitters for weather radars • WWII: Weather echoes identified as clutter on military radars (Atlas et. al., 1990)
• 1950s: Application of backscatter matrix in radar (Kennaugh, Ohio State)
Simultaneous observations of D3R and CHILL during a rain event (Nov 1, 2011) 47/61
(Chandrasekar et. al., "Characterization of NASA Ku-Ka Band Dual-Frequency Dual-Polarized Doppler Radar (D3R)", Precipitation Measurement Missions (PMM) Science Team Meeting, 2010)
MS Final Exam
Comparison of Dual-Polarimetric Variables
04/27/2010
Simultaneous observations of D3R and CHILL
during an intense storm (July 10, 2011) 48/61
(Chandrasekar et. al., "Characterization of NASA Ku-Ka Band Dual-Frequency Dual-Polarized Doppler Radar (D3R)", Precipitation Measurement Missions (PMM) Science Team Meeting, 2010)
MS Final Exam
Observations during sphere calibration experiment
04/27/2010
Top: Near (13.9 km) range observation on D3R real-time display during
sphere calibration experiment at CSU-CHILL radar site on Sept 23,
2011. Bottom: The same observation at the far range (31.4 km). 49/61
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Deployment at GCPEx Campaign
• D3R deployed at Environment
Canada (EC) Center for
Atmospheric Research
Experiments (CARE) site in
Egbert, Ontario to participate in
GCPEx
• The radar operated
uninterrupted from Jan 17, 2012
to Mar 1, 2012.
• Diverse meteorological events
observed by D3R (lake effect
snow, freezing rain, freezing
drizzle, light rain, light snow
flurries, heavy synoptic snow
etc.)
• New waveform with revised
calibration used
D3R deployed at Environment Canada site in
Egbert, Canada during GPM Cold Season
Precipitation Experiment (GCPEx) (01/14/2012)
Photograph by: Kumar Vijay Mishra
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D3R WKR WKR D3R
Zh
V
Example data from GCPEx campaign: Comparison between D3R and C-band WKR radar (Jan 17, 2012)
51/61 Comparison of D3R and WKR (Chandrasekar et. al., "Dual-Frequency Dual-Polarized Doppler Radar (D3R) System for GPM Ground Validation: Update and Recent Field
Observations", IGARSS, 2012)
MS Final Exam
RHIs (Skydive Az = 87.8 deg) Passing rain-band and weakening melting layer
Jan 23 2012 Zh: 1437 UTC Zh: 1447 UTC
Zh: 1457 UTC Zh: 1507 UTC Zh: 1517 UTC Zh: 1526 UTC
• Melting layer at ~2.2 kms.
• Melting layer weakens in subsequent scans as the rain band crosses the sector.
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Cold rain observation on Ku and Ka RHIs (Skydive Az = 87.8 deg)
Jan 26, 2012
Ku Zh
0202 UTC
Ka Zh
0225 UTC 0244 UTC 0307 UTC 0329 UTC 0345 UTC
• Observation of mammatus clouds, brightband formation and freezing rain
• ~20 min snapshots from a set of RHI scans @ every 10 mins
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WKR Over-the-head RHIs
(Light snow event: 10 min snapshots)
D3R Ku Zh
WKR Reverse RHI
17:25:20-17:26:49
UTC
D3R Ku Zh
WKR RHI
17:27:04-17:28:29
UTC
D3R Ku Zh
WKR Reverse RHI
17:34:39-17:36:06
UTC
D3R Ku Zh
WKR RHI
17:36:16-17:37:45
UTC
D3R Ku Zh
WKR RHI
17:45:39-17:47:12
UTC
D3R Ku Zh
WKR Reverse RHI
17:43:54-17:45:28
UTC
Light snow echoes weaker than -5dBZ observed by Ku-band (Jan 28, 2012)
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Observations of an intense snow storm (Feb 29, 2012)
D3R Ku Zh
V
W
18:32 Z 19:32 Z 20:32 Z 21:32 Z
MS Final Exam
2012-02-29: Frequent Sampling of
Intense Snow Band
• 10 min snapshots of D3R RHI scans @ every 5 mins
• All RHIs: El = 1-60°
Ku Zh Mortons RHI
20:44 Z
Ku Zh KCR RHI
20:45 Z
Ku ρhv V-point
20:46 Z
Ku Zh Low El PPI
20:42 Z
Ku Zh Mortons RHI
20:54 Z
Ku Zh KCR RHI
20:53 Z
Ku ρhv V-point
20:55 Z
Ku Zh Low El PPI
20:52 Z 2042 Z 2052 Z
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Outline
• Introduction
• Context of Solid-State Transmitters in Weather Radars
• Existing Weather Radar Digital IF Receivers
• Digital Receiver solution for Solid-State Transmitter
Weather Radars
• Multi-Channel Receiver Design
• Processing Modes
• NASA D3R System
• First Results from Field Deployment
• Summary
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MS Final Exam
Summary
• A multi-channel digital receiver was designed, developed, tested
and deployed
• Implements an advanced frequency-diversity waveform
• Sidelobe performance is satisfactory for weather radars
• The data from the three pulses is merged seamlessly
• Real-time signal processor developed for the digital receiver
• Successful deployment in D3R radar
• Comparison with an S-band and C-band radar indicates the
products are correctly estimated
• Future work
• Phase-coding capability and alternate mode of transmission to be tested
• Real-time clutter suppression and attenuation correction algorithms to be
included in the signal processor 58/61
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Acknowledgments
Dr. V. Chandrasekar, Adviser
Dr. Anura Jayasumana, Committee Member
Dr. Paul Mielke Jr., Committee Member
Mathew Schwaller, Project Manager, NASA Goddard Space Flight Center
Patrick Kennedy , Facility Manager, CSU-CHILL
David Brunkow, Senior Engineer, CSU-CHILL
All former and current members of
CSU Radar and Communication Lab
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References
04/27/2010
• Kumar Vijay Mishra, V. Chandrasekar, Cuong Nguyen and Manuel Vega, "The Signal Processor System for the NASA Dual-Frequency Dual-Polarized Doppler Radar", IGARSS 2012, Munich.
• Kumar Vijay Mishra, V. Chandrasekar, Cuong Nguyen and Manuel Vega, "Waveform Design and Implementation for the Solid-State NASA Dual-Frequency Dual-Polarized Doppler Radar", IGARSS 2011, Vancouver.
• Jim George, Kumar Vijay Mishra, Cuong Nguyen and V. Chandrasekar, "Implementation of Blind Zone and Range-Velocity Ambiguity Mitigation for Solid-State Weather Radar", IEEE International Radar Conference, 2010, Washington DC.
• Nitin Bharadwaj, Kumar Vijay Mishra and V. Chandrasekar, "Waveform Considerations for Dual-Polarization Doppler Weather Radar with Solid-State Transmitters", IGARSS 2009, Cape Town
• Cuong M. Nguyen, V. Chandrasekar, Kumar Vijay Mishra, and J. George, "Sensitivity enhancement system for pulse compression weather radar", 35th AMS Conference on Radar Meteorology, 2011, Pittsburgh.
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Thank you
“See how that one little cloud floats like a pink feather from some gigantic flamingo. Now the red rim of the sun pushes itself over the London cloudbank.”
Sherlock Holmes’ observations on clouds The Sign of Four by Sir Arthur Conan Doyle, 1890