CALIBRATION AND PERFORMANCE OF THE HAMSR INSTRUMENT DURING THE NASA GRIP CAMPAIGN

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 : [email protected]

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]


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]


10 20 30 40 50 60 70 80

340

340.5

341

341.5

342

342.5

Pixel Number

Tem

per

atu

re [

K]


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

]


500 1000 1500 2000

310

320

330

340

Scan Number (#)

Tem

per

atu

re [

K]


500 1000 1500 2000

310

320

330

340

Scan Number (#)

Tem

per

atu

re [

K]


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

]


500 1000 1500 2000

310

320

330

340

Scan Number (#)

Tem

per

atu

re [

K]


500 1000 1500 2000

310

320

330

340

Scan Number (#)

Tem

per

atu

re [

K]


500 1000 1500 2000

21.5

22

22.5

23

23.5

Scan Number (#)

Gai

n [

C/K

]


500 1000 1500 2000

310

320

330

340

Scan Number (#)

Tem

per

atu

re [

K]


500 1000 1500 2000

310

320

330

340

Scan Number (#)

Tem

per

atu

re [

K]


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

]


2000 4000 6000 8000 10000 12000 14000 16000 18000

310

320

330

340

350

360

370

Scan Number (#)

Tem

per

atu

re [

K]


2000 4000 6000 8000 10000 12000 14000 16000 18000

310

320

330

340

Scan Number (#)

Tem

per

atu

re [

K]


2000 4000 6000 8000 10000 12000 14000 16000 18000

50

52

54

56

58

Scan Number (#)

Gai

n [

C/K

]


2000 4000 6000 8000 10000 12000 14000 16000 18000

310

320

330

340

Scan Number (#)

Tem

per

atu

re [

K]


2000 4000 6000 8000 10000 12000 14000 16000 18000

310

320

330

340

Scan Number (#)

Tem

per

atu

re [

K]


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

]


2000 4000 6000 8000 10000 12000300

320

340

360

380

Scan Number (#)

Tem

per

atu

re [

K]


2000 4000 6000 8000 10000 12000

330

335

340

345

350

Scan Number (#)

Tem

per

atu

re [

K]


2000 4000 6000 8000 10000 12000

50

52

54

56

58

60

62

Scan Number (#)

Gai

n [

C/K

]


2000 4000 6000 8000 10000 12000

338

340

342

344

Scan Number (#)

Tem

per

atu

re [

K]


2000 4000 6000 8000 10000 12000

337

338

339

340

341

342

343

Scan Number (#)

Tem

per

atu

re [

K]


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 [

%]


NEDT Flag

Unusable Flag

500 1000 1500 2000

21.5

22

22.5

23

23.5

Scan Number (#)

Gai

n [

C/K

]


500 1000 1500 2000

310

320

330

340

Scan Number (#)

Tem

per

atu

re [

K]


500 1000 1500 2000

310

320

330

340

Scan Number (#)

Tem

per

atu

re [

K]


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

]


2000 4000 6000 8000 10000 12000

338

340

342

344

Scan Number (#)

Tem

per

atu

re [

K]


2000 4000 6000 8000 10000 12000

337

338

339

340

341

342

343

Scan Number (#)

Tem

per

atu

re [

K]


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 [

%]


NEDT Flag

Unusable Flag

0 5 10 15 20 250

5

10

15

20

25

30

35

Channel Number [#]

Pix

els

Fla

gg

ed [

%]


NEDT Flag

Unusable Flag

2000 4000 6000 8000 10000 12000

39

40

41

42

Scan Number (#)

Gai

n [

C/K

]


2000 4000 6000 8000 10000 12000

339

340

341

342

343

344

Scan Number (#)

Tem

per

atu

re [

K]


2000 4000 6000 8000 10000 12000

339

340

341

342

343

344

Scan Number (#)

Tem

per

atu

re [

K]


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



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

Documents

CALIBRATION AND PERFORMANCE OF THE HAMSR INSTRUMENT DURING THE NASA GRIP CAMPAIGN