calibration and performance of the hamsr instrument during the nasa grip campaign
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CALIBRATION AND PERFORMANCE OF THE HAMSR INSTRUMENT DURING
THE NASA GRIP CAMPAIGN
Boon Lim*, Shannon Brown, Richard Denning, Pekka Kangaslahti, Bjorn Lambrigtsen,
Jordan Tanabe, and Alan Tanner
Jet Propulsion Laboratory*Contact : Boon.H.Lim@jpl.nasa.gov
Outline• HAMSR Overview• Genesis and Rapid Intensification Processes (GRIP) Campaign• Data System• Thermal Environment• External target – Stability, Gradients, Reflection• Nominal Calibration (V0)• Receiver Temperature Calibration (V1)• Calibration Comparison (V0 vs V1)• HAMSR Performance• Summary
7/29/2011 IGARSS 2011 2
HAMSR Overview• High Altitude MMIC Sounding Radiometer (HAMSR)• 3 Sounding Bands (55, 118 and 183 GHz)• 25 total channels• Oxygen and Water Vapor Bands for Profiling• Cross-Track Scanner with Ambient/Hot External
Calibration Targets• Product of ESTO (IIP, ACT and AITT)
– Entering 15th Year – Participated in 5 Campaigns– Integrated on 3 Aircraft
7/29/2011 IGARSS 2011 3
GRIP Campaign• Genesis and Rapid Intensification Processes Campaign
– 5th Coordinated Hurricane Field Campaign Since 1998– NOAA, NSF and the AF
• From August to September 2010• DC-8 (9), Global Hawk (4) and WB-57 (2)
– Approximately 300 flight hours
• Hurricane Frank (Pacific), Tropical Storm Matthew (Atlantic), Hurricanes Earl and AL-92/Karl (Atlantic)– Global Hawk Stationed at Dryden– Over 120 Flight Hours for the Global Hawk– 20 Eye Overpasses Hurricane Karl (~13 Hours)– Typical flight duration 24 Hours
7/29/2011 IGARSS 2011 4
GRIP Flights
7/29/2011 IGARSS 2011 5
Frank08/28/2010
Earl09/02/2010
Matthew09/23/2010
AL9209/12/2010
Karl09/16/2010
HAMSR Imagery During GRIPHAMSR Imagery During GRIP
Hurricane Earl 2010
Hurricane Matthew Platform Report – Scott Braun
7/29/2011 IGARSS 2011 7
HAMSR GRIP Ground Data SystemHAMSR GRIP Ground Data System
GHOC
HAMSR ground data processor
netC
DF
L1B
file
sJP
L Hur
rican
e Por
tal
HAMSR website
quick look images
RTMM
Commanding
Data downlink
HAMSR software upgraded after GRIP to provide real-time imagery over Iridium
Successfully tested during 2011 WISPAR campaign
Past 30 minutes
Past 60 minutes
Full Dataset
Select HAMSR channel – TB imagery-Full data set, past 30 minutes or past 60 minutes
HAMSR RTMM Display for GRIP
Thermal Environment• HAMSR Sits in an Unpressurized Pod• RF Section is Thermally Insulated with Styrofoam• Temperature Controlled Heaters on the RF Plates
– Thermistors Available Across the Instrument– RF Components (RF/IF LNAs, Mixers), RF Plate Temperatures, Motor,
Power Supply, Digital System, Computer, Etc
• Fans for Circulation of Air– On Runway if Temperatures Exceed a Threshold
• At Flight Altitude (~17 km)– Temperature Typically -150C
7/29/2011 IGARSS 2011 10
WISPAR 2011- Thermal Environment
7/29/2011 IGARSS 2011 11
External Target - Stability• Thermistors Embedded in Targets• Ambient Target Drifts Freely
– Rate of Change 6-7oC/Hour
• Hot Target Held at ~68oC– Oscillation at 120 Second Period, 0.01K<
7/29/2011 IGARSS 2011 12
18:00 00:00 06:00 12:00-20
-15
-10
-5
0
5
10
15
20
Time
Te
mp
. 0C
Ambient Target Temperatures
55 Amb
183 Amb
18:00 00:00 06:00 12:0067.6
67.8
68
68.2
68.4
68.6
Time
Te
mp
. 0C
Heated Target Temperatures
55 Hot
183 Hot
06:05 06:10 06:15
67.604
67.605
67.606
67.607
67.608
67.609
67.61
67.611
67.612
Time
Te
mp
. 0C
Heated Target Temperatures
183 Hot
External Target - Gradients• Gradients Across the Target Pixels
– Typically Monotonic– Magnitude Under 0.3K– Easily Mitigated with Averaging
7/29/2011 IGARSS 2011 13
10 20 30 40 50 60 70 80
339.5
340
340.5
341
341.5
342
Pixel Number
Tem
per
atu
re [
K]
Temperature Variation Across Calibration Target, Channel 20
10 20 30 40 50 60 70 80
339.5
340
340.5
341
341.5
342
Pixel Number
Tem
per
atu
re [
K]
Temperature Variation Across Calibration Target, Channel 13
External Target - Reflections• Standing Waves Setup in the Middle of the Target
– Despite Low Return Loss Material (~35 dB)– Only in Several Frequencies– Remove Central Pixels
7/29/2011 IGARSS 2011 14
10 20 30 40 50 60 70 80
340
340.5
341
341.5
342
342.5
Pixel Number
Tem
per
atu
re [
K]
Temperature Variation Across Calibration Target, Channel 2
10 20 30 40 50 60 70 80
340
340.5
341
341.5
342
342.5
Pixel Number
Tem
per
atu
re [
K]
Temperature Variation Across Calibration Target, Channel 7
Initial Processing• Moving Average of the Hot and Ambient Counts
– Period of the Heating Oscillation (~110 Seconds)
• Time ‘Shift’ in Ambient Counts– Account for linear time drifts
• Calculate Per-Scan Gain– Gain = (CHot – CAmb)/(THot – TAmb) [C/K]
• Flag Unusable Pixels (-2)– Insufficient Separation of the Hot and Ambient Targets– Differential Temperatures on Targets, 5xNEDT– Differential Gain, Threshold (empirical)
7/29/2011 IGARSS 2011 15
Nominal Processing• Moving Average of Gain• Calculate Antenna
Temperature– TA = (Ct – CAmb)/Gain + TAmb
• Standard Calibration Stratagy
• Gain Drifts/Jumps Distributed in the Averaging
• Incorrectly Processes ‘Good’ Data
7/29/2011 IGARSS 2011 16
500 1000 1500 2000
21.5
22
22.5
23
23.5
Scan Number (#)
Gai
n [
C/K
]
Smoothed Gain Per Scan, Channel 25, htbV0
500 1000 1500 2000
310
320
330
340
Scan Number (#)
Tem
per
atu
re [
K]
Tb, Unusable Points Removed, Channel 25, htbV0
500 1000 1500 2000
310
320
330
340
Scan Number (#)
Tem
per
atu
re [
K]
Tb, NEDT Points Removed, Channel 25, htbV0
Receiver Temperature Calibration• Calculate Receiver Temperature
– TRx = CAmb/Gain - TAmb
• Smooth Receiver Temperature• Calculate Gain (from Hot Target)
– GHot = CHot/(TRx+CHot)
• Calculate Gain (from Ambient Target)– GAmb = CAmb/(TRx+CAmb)
• Average Gain– Gain = (GHot+GAmb)/2
• Calculate Ta– TA = (Ct – CAmb)/Gain + TAmb
7/29/2011 IGARSS 2011 17
500 1000 1500 2000
21.5
22
22.5
23
23.5
Scan Number (#)
Gai
n [
C/K
]
Smoothed Gain Per Scan, Channel 25, htbV1
500 1000 1500 2000
310
320
330
340
Scan Number (#)
Tem
per
atu
re [
K]
Tb, Unusable Points Removed, Channel 25, htbV1
500 1000 1500 2000
310
320
330
340
Scan Number (#)
Tem
per
atu
re [
K]
Tb, NEDT Points Removed, Channel 25, htbV1
Comparison – Gain Smoothing
7/29/2011 IGARSS 2011 18
500 1000 1500 2000
21.5
22
22.5
23
23.5
Scan Number (#)
Gai
n [
C/K
]
Smoothed Gain Per Scan, Channel 25, htbV0
500 1000 1500 2000
310
320
330
340
Scan Number (#)
Tem
per
atu
re [
K]
Tb, Unusable Points Removed, Channel 25, htbV0
500 1000 1500 2000
310
320
330
340
Scan Number (#)
Tem
per
atu
re [
K]
Tb, NEDT Points Removed, Channel 25, htbV0
500 1000 1500 2000
21.5
22
22.5
23
23.5
Scan Number (#)
Gai
n [
C/K
]
Smoothed Gain Per Scan, Channel 25, htbV1
500 1000 1500 2000
310
320
330
340
Scan Number (#)
Tem
per
atu
re [
K]
Tb, Unusable Points Removed, Channel 25, htbV1
500 1000 1500 2000
310
320
330
340
Scan Number (#)
Tem
per
atu
re [
K]
Tb, NEDT Points Removed, Channel 25, htbV1
Comparison – Spikes
7/29/2011 IGARSS 2011 19
2000 4000 6000 8000 10000 12000 14000 16000 18000
50
52
54
56
58
Scan Number (#)
Gai
n [
C/K
]
Smoothed Gain Per Scan, Channel 4, htbV0
2000 4000 6000 8000 10000 12000 14000 16000 18000
310
320
330
340
350
360
370
Scan Number (#)
Tem
per
atu
re [
K]
Tb, Unusable Points Removed, Channel 4, htbV0
2000 4000 6000 8000 10000 12000 14000 16000 18000
310
320
330
340
Scan Number (#)
Tem
per
atu
re [
K]
Tb, NEDT Points Removed, Channel 4, htbV0
2000 4000 6000 8000 10000 12000 14000 16000 18000
50
52
54
56
58
Scan Number (#)
Gai
n [
C/K
]
Smoothed Gain Per Scan, Channel 4, htbV1
2000 4000 6000 8000 10000 12000 14000 16000 18000
310
320
330
340
Scan Number (#)
Tem
per
atu
re [
K]
Tb, Unusable Points Removed, Channel 4, htbV1
2000 4000 6000 8000 10000 12000 14000 16000 18000
310
320
330
340
Scan Number (#)
Tem
per
atu
re [
K]
Tb, NEDT Points Removed, Channel 4, htbV1
Comparison – Robustness
7/29/2011 IGARSS 2011 20
2000 4000 6000 8000 10000 12000
50
52
54
56
58
60
62
Scan Number (#)
Gai
n [
C/K
]
Smoothed Gain Per Scan, Channel 18, htbV0
2000 4000 6000 8000 10000 12000300
320
340
360
380
Scan Number (#)
Tem
per
atu
re [
K]
Tb, Unusable Points Removed, Channel 18, htbV0
2000 4000 6000 8000 10000 12000
330
335
340
345
350
Scan Number (#)
Tem
per
atu
re [
K]
Tb, NEDT Points Removed, Channel 18, htbV0
2000 4000 6000 8000 10000 12000
50
52
54
56
58
60
62
Scan Number (#)
Gai
n [
C/K
]
Smoothed Gain Per Scan, Channel 18, htbV1
2000 4000 6000 8000 10000 12000
338
340
342
344
Scan Number (#)
Tem
per
atu
re [
K]
Tb, Unusable Points Removed, Channel 18, htbV1
2000 4000 6000 8000 10000 12000
337
338
339
340
341
342
343
Scan Number (#)
Tem
per
atu
re [
K]
Tb, NEDT Points Removed, Channel 18, htbV1
Flag Marginal Pixels• Pixels that Exhibit Larger than Expected Noise
– Temperature is Over 3.5x NEDT– Empirical Value for Each Channel– For End-Product Users
7/29/2011 IGARSS 2011 21
0 5 10 15 20 250
2
4
6
8
10
12
Channel Number [#]
Pix
els
Fla
gg
ed [
%]
Flagging Algorithms Check, htbV0
NEDT Flag
Unusable Flag
0 5 10 15 20 250
2
4
6
8
10
12
Channel Number [#]
Pix
els
Fla
gg
ed [
%]
Flagging Algorithms Check, htbV1
NEDT Flag
Unusable Flag
500 1000 1500 2000
21.5
22
22.5
23
23.5
Scan Number (#)
Gai
n [
C/K
]
Smoothed Gain Per Scan, Channel 25, htbV1
500 1000 1500 2000
310
320
330
340
Scan Number (#)
Tem
per
atu
re [
K]
Tb, Unusable Points Removed, Channel 25, htbV1
500 1000 1500 2000
310
320
330
340
Scan Number (#)
Tem
per
atu
re [
K]
Tb, NEDT Points Removed, Channel 25, htbV1
Marginal Pixels
7/29/2011 IGARSS 2011 22
2000 4000 6000 8000 10000 12000
50
52
54
56
58
60
62
Scan Number (#)
Gai
n [
C/K
]
Smoothed Gain Per Scan, Channel 18, htbV1
2000 4000 6000 8000 10000 12000
338
340
342
344
Scan Number (#)
Tem
per
atu
re [
K]
Tb, Unusable Points Removed, Channel 18, htbV1
2000 4000 6000 8000 10000 12000
337
338
339
340
341
342
343
Scan Number (#)
Tem
per
atu
re [
K]
Tb, NEDT Points Removed, Channel 18, htbV1
Flag Marginal Pixels Second Check• Receiver Temperature Calibration• Close to the Theoretical Values for Noise
7/29/2011 IGARSS 2011 23
0 5 10 15 20 250
5
10
15
20
25
30
35
Channel Number [#]
Pix
els
Fla
gg
ed [
%]
Flagging Algorithms Check, htbV1
NEDT Flag
Unusable Flag
0 5 10 15 20 250
5
10
15
20
25
30
35
Channel Number [#]
Pix
els
Fla
gg
ed [
%]
Flagging Algorithms Check, htbV0
NEDT Flag
Unusable Flag
2000 4000 6000 8000 10000 12000
39
40
41
42
Scan Number (#)
Gai
n [
C/K
]
Smoothed Gain Per Scan, Channel 8, htbV1
2000 4000 6000 8000 10000 12000
339
340
341
342
343
344
Scan Number (#)
Tem
per
atu
re [
K]
Tb, Unusable Points Removed, Channel 8, htbV1
2000 4000 6000 8000 10000 12000
339
340
341
342
343
344
Scan Number (#)
Tem
per
atu
re [
K]
Tb, NEDT Points Removed, Channel 8, htbV1
Instrument Performance• As Derived from the Data
– Hurricane Karl
• 55 GHz Performs the Poorest– Legacy Hardware– Upgrade in Progress (~4dB)
• 118 GHz and 183 GHz Upgraded During AITT
• Performance is as Expected from the Receiver Temperatures
• 99.9% Up-Time– 1 Channel Dropped Out for 3
Hours
7/29/2011 IGARSS 2011 24
Summary• External Targets Well Characterized• HAMSR Successfully Participated in GRIP Campaign
– Data System Utilized High Bandwidth Link (‘Real-Time’)– Utility was Immediate in Directing the GH Flight Path
• Calibration Methodology Relies on Stability of Receivers– Front End LNAs vs Entire Gain Chain
• HAMSR Receivers as a System Perform to Measured Receiver Temperatures
• WISPAR Campaign Had Coincident Dropsondes– Absolute Calibration Comparison Pending
• Instrument calibration and characterization (Brown et al., TGRS, in press)
7/29/2011 IGARSS 2011 25
Backup Slides• HAMSR Timeline• HAMSR Block Diagram• External Target Construction• Pre-Flight Evaluation• Allan Variance LN2 Stare• GRIP – Agency Coordination• Danielle, Earl and Fiona
7/29/2011 IGARSS 2011 26
HAMSR Timeline
7/29/2011 IGARSS 2010=1 27
HS3
Grip (GH)
NASA AITT
NAMMA (DC-8)
TCSP (ER-2)
CAMEX-4 (ER-2)
NASA IIP
IMAS
1994 1996 1998 2000 2002 2004 2006 2008 2010 2012
HAMSR Block Diagram
7/29/2011 IGARSS 2011 28
ScanningMotor
Encoder
Cal. Targets
Cal. Targets
DichroicPlate
183 GHzRadiometer7 Channels
118 GHzRadiometer10 Channels
55 GHzRadiometer8 Channels
Digitizers16-Bit
Digitizers16-Bit
FPGAFreeForm Digital IO
Spartan 3E
SPI Bus
CPUAMPRO
Readyboard 620
8-bit ISA
Thermistors40 Channels
16-Bit
RS486-RS232Converter
NAV420CAGPS and Telemetry
HAMSR
Ethernet
Mylar Apertures
Operator ComputerSystem ConfigurationData Processing
Global Hawk HAMSR Data DownlinkAircraft GPS and Telemetry
External Target - Construction• Pyramidal Blackbody Calibration Targets
– Ambient and ~680C
• Commercial Product with -50dB Return Loss Spec– Heavy Aluminium Coated with a Ferrite Loaded Epoxy Absorbing
Material– 16x12 cm Area, 4 cm Long Pyramids, 1 cm Apart at Tips
• 4 Thermistors Embedded in Targets at the Tips• Insulated in Styrofoam
– ~35dB Return Loss
7/29/2011 IGARSS 2011 29
Pre-Flight Evaluation – Scan Bias
7/29/2011 IGARSS 2011 30
• Within the field of view, minimal bias in the various channels
• 50 GHz channels: – Bias < 0.5 K for -45o < θ < 45o
• 118/183 GHz channels: – Bias < 0.25 K for -45o < θ < 45o
Allan Variance LN2 Stare
7/29/2011 IGARSS 2011 31
GRIP – Agency Coordination
7/29/2011 IGARSS 2011 32
Danielle, Earl and Fiona
7/29/2011 IGARSS 2011 33
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