CSU-CHILL Update S/X band development and recent operations - PowerPoint Presentation

Slide1

CSU-CHILL UpdateS/X band development and recent operationsSolid State transmitter projectSlide2

CSU-CHILL Radar Architecture

Antenna

Radome

Radar Trailer

Signal

Processor

Antenna

Servos

Dual

Transmitters

Dual

Receivers

Waveform Generator

Digitizer,

Filtering

Network

System

Control

Storage

Processor

Mass

Storage

Local

Display,

Control

Gateway

Sync

Angle

Internet

Remote

Display,

Control

GUI with S-

polKa

March 4, 2013

VCHILL

CSU-CHILL visit for ATS741Slide3

CSU-CHILL AntennaDual-offset Gregorian antennaChoice of three symmetric OMT feed hornsS-band only

X-band only

Dual wavelength, S/X

S-band

beamwidth

1 degreeX-band beamwidth

0.3 degreeTwo way s

idelobe levels better than 50 dB at S-band; 70 dB at X-bandSingle-wavelength feeds achieve exceptional cross-polar isolation better than 50 dBMedian LDR in light rain of -38 dB

Main reflector

Feed horn

March 4, 2013

3

CSU-CHILL visit for ATS741

SubreflectorSlide4

Dual frequency (S and X-Band) horn installed on 8.5m diameter dual-offset antennaX-Band 3 dB beam width ~0.3 deg; beam axis coincident with S-bandSlide5

X-Band hardware adopted from UPRM MRI radar (CSU ECE collaboration effort)

Development of X-band

r

adar addition to CSU-CHILLSlide6

S/X-Band PPI data: Convergence patterns along eastern edge of convective echoes

Higher resolution at X-band is readily evident

X-band data not corrected for attenuation

X-band delivers nearly same range sensitivity as S-band despite significantly lower power.

Antenna gain is 54

db

! Gain ~ Area/λ

2

S-band

X-bandSlide7

Better differential propagation phase sensitivity at X-Band vs. S-

Band

Significant advantage for cold season precipitation and microphysics

“Negative”

phidp

more evident at X-band,

i

ndicating vertically aligned ice crystals oriented

b

y an electric fieldSlide8

Attenuation

correctionSlide9

FROST 2013carried out by CSU (Rutledge, Kennedy) and NCAR/RAL (Kumjian

, Rasmussen, Metro State students); 20 hour project

CHILL X-band; NCAR X-band plus assortment of surface measurements at NCAR Marshall Field site

s

oundings

documented many winter storms, many overnight (autonomous) operations conductedCHILL X-band

polarimetric observations at high resolution Slide10
Slide11

HEAVY AGGREGATE SNOWFALL CAUSED

MAJOR TRAFFIC ACCIDENT ON I-25Slide12
Slide13

15 April 2013

1709 UTC

145 degree RHI

Impressive convective scale

g

enerating cellsSlide14
Slide15

Aggregates

Pristine crystals

FallstreakSlide16

More examplesf

Z

Zdr

rhohv

Wednesday 11:52 MDTSlide17

Solid-state S-band Transmitter upgrade for CSU-CHILLASR-11 solid state transmitter donated to CSU by RaytheonSlide18

High level goalsAt the NSF radar workshop, strategic benefits of solid-state class radar transmitters were discussed and emphasized for modern weather radars, both from advanced measurement perspective as well as long term measurements, and robust remote operations for climate observations.

CSU-CHILL is a very advanced weather radar ,with aligned dual-frequency dual-polarization antenna, and state of the art signal processor. The transmitter is the only component that is “classic”, and was the limiting factor in advancement.

Air surveillance radars (ASR) operate in the lower S-band, same as weather radar and they have access to solid state transmitters.

Demonstrate that the ASR class transmitter can be used effectively for dual-polarization implementation for weather radars.

This upgrade will keep CSU-CHILL radar at the forefront of research weather

radars

This is being developed as a common platform that can be deployed with other S-band radars such as N-Pol and S-

polKaSlide19

Solid-state transmitter plan

Waveguide

Switch

Klystron

Transmitter

Solid-state Transmitter

Common Signal Processor

Radar Users

S-

polKaSlide20

Advantages of Solid-state transmitterFrom a facility perspective, the first and foremost is the ability to have state of the art, robust transmitter

for weather radar, with enhanced,

fully remote operation

for field deployments

Range-Velocity

Ambiguity Mitigation

, through the use of frequency diversity and coding diversity offer improved performance over current

techniquesData Quality Improvement, specifically, reduced variance in estimated parameters, due to range-averaging of the additional independent samples introduced by both Frequency Diversity and Pulse Compression.

Faster Scanning of a volume, without sacrificing data quality, due to range-averaging of the additional independent samples introduced by both Frequency

Diversity as well as

Pulse CompressionSlide21

Timeline of major events

Major events and milestones on the development timeline are shown

Each subsystem is considered complete after it has been bench-tested

ASR-11 transmitter Slide22

CSU-CHILL projectsMajor support for DC3 in summer 2012; NSF REU 2012Winter 2013, FROST (20 hour in collaboration with NCARThree spring 2013 VCHILL remote tours/instruction; SUNY Oswego, North Carolina State and Iowa State

Summer 2013 projects include NSF REU and

Unmanned Aircraft System Sensor Calibration

(U. of Nebraska), several 20 hour projects

Summer 2014, FRONT-PORCH (proposed) Slide23

AMS Short Course on Weather Radar Calibration Laboratory: 14 Sept 2013, CSU-CHILL Site , COThe goal of the course is to provide not just the theory, but practical demonstrations calibration methods, so that the practitioners understand the intricacies of good calibration. The course is aimed at students and scientists who desire to know the details of radar calibration from a practitioner’s view point.

The course will be divided into two parts. The first will describe briefly the fundamental physical principles of calibrating radar and the special aspects of calibrating weather radar.  This segment will also introduce the recent advances such as calibration of dual-polarization radar.  The second part will demonstrate the practical procedures, and with emphasis on laboratory style work

.

The organizer and chief instructor of this course is Prof  V.

Chandrasekar

, Colorado State University. He will be joined by leading experts in the field, namely, Prof Paul Smith (Professor Emeritus SDSM&T),

Dr

Nitin Bharadwaj ( PNNL ) and Dr

Luca Baldini ( ISAC).