tangent height accuracy of superconducting submillimeter-wave limb-emission sounder (smiles) on...

Tangent height a ura y ofSuper ondu tingSubmillimeter-WaveLimb-Emission Sounder(SMILES) on InternationalSpa e Station (ISS)O hiai Satoshi (NICT, Tokyo, Japan)Nishibori Toshiyuki (JAXA, Tsukuba, Japan)Kiku hi Ken-i hi (NICT, Tokyo, Japan)Mizobu hi Satoko (JAXA, Tsukuba, Japan)Manabe Takeshi (Osaka Pref. Univ., Japan)Mitsuda Chihiro (Fujitsu FIP, Tokyo, Japan)Philippe Baron (NICT, Tokyo, Japan)Ueno Shiro (JAXA, Tsukuba, Japan)

IGARSS 2012, Muni h, Germany, 2012/07/24

TU4.6.3

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the Super ondu ting Submillimeter-Wave Limb-Emission Sounder (SMILES)the International Spa e Station (ISS) 1 m (H)0.8 m (W)1.8 m(L)476 kg

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Contents

pp.4−13pp.14−18pp.19−25

Title:Tangent height a ura y of Super ondu ting Submillimeter-WaveLimb-Emission Sounder (SMILES) on International Spa e Station (ISS)Introdu tion of SMILES,in luding performan e results and alibration issuesISS attitudeTangent height a ura y ofthe SMILES observation

IGARSS 2012 Tangent height a ura y of SMILES on ISS, o hiai�ni t.go.jp3/26


SMILES (Super ondu ting Submillimeter-Wave Limb-Emission Sounder)

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SMILES is the se ond payload from this side.

• SIS re eivers in 625 and 650 GHz bands;very high sensitivity for submillimeter-wavelimb-emission observation• Atmospheri observation on ISS:from O t. 2009 to Apr. 2010• Target spe ies:O3, HCl, ClO, HOCl, HO2, HNO3, CH3CN,and BrO;Also stratospheri wind, UTLS water vaporand i e louds.• Developed jointly by NICT and JAXA

National Institute of Informationand Communi ations Te hnology Japan Aerospa eExploration Agen y


SMILES Instrument

624.3-626.3 GHz 1.55-2.75 GHz

1.55-2.75 GHz

Sw

itch

Mat

rix AOS AU1

Spectrometers

CalibrationHot Load

Cold Sky Terminator

from

Atmospheric

Limb

SwitchMirror

Main Reflector

IF Amplification Section

39.2 cm x 20 cm

FSPs

11-12.2 GHz

11.8-13 GHz

11.8-13 GHz

4 K

16 K

76 K

SISMixers

JT

293 K

SMI

BBH

BBH

637.32 GHz

Submm Local Osc.

Stir

ling

Comb Generator

Do

wn

Co

nve

rter

s

Att

enu

ato

rs

Star Cameras

Data Processor & Controller

Cryostat

I/F to JEM

649.1-650.3 GHz

AOS AU2

Frequen ies :LSB : Band A: 624.26− 625.59 GHz,Band B: 625.06− 626.38 GHz,USB : Band C: 649.05− 650.38 GHzFrequen y Resolution / Bandwidth: (two AOS units)about 1.1 MHz / 1.3 GHz


Antenna and Opti sLocal Oscillator(637.32 GHz)

fromAntenna

ColdTermination

Sideband SeparatorElevation steerable antennaAperture: 392 mm× 200 mmBeam widths (�3 dB): 0.089◦ × 0.173◦Height resolution at tangent point: 3.2 kmSIS re eivers are lo ated belowthe sideband separatorSubmillimeter Opti sin ludes sideband separator, lo al diplexer.The opti s is installed in a shielded box.


SubMM Re eiver and Cryo ooler

Inside of Cryostat Compressors

Cryostat

Optics incl. SSB separtor, submm-LO

4 K

20 K

100 K

HEMT amps.

SIS mixers

SIS mixer operated at 4.3 K

Submm Re eiver (Super ondu ting mixer)Two re eivers in 624− 626 and 649− 650 GHzSystem noise temperature is 315−320 K in SSB operationCryo ooler (Joule-Thomson y le and Stirling oolers)Cooling Capa ity : 20 mW � 4.3 KPower Consumption : 120 W nominal � BOLMass : 82 kg (in l. Cryostat: 24 kg)


Re eiver Performan e

200

250

300

350

400

450

500

624.4 624.6 624.8 625 625.2 625.4

TS

YS (

SS

B)

[K]

Frequency [GHz]

Band A (LSB receiver)

Maximum in Orbit

Minimum in Orbit

Prelaunch Test

200

250

300

350

400

450

500

625.2 625.4 625.6 625.8 626 626.2

TS

YS (

SS

B)

[K]

Frequency [GHz]

Band B (LSB receiver)

200

250

300

350

400

450

500

649.2 649.4 649.6 649.8 650 650.2

TS

YS (

SS

B)

[K]

Frequency [GHz]

Band C (USB receiver)

1e-07

1e-06

1e-05

1e-04

0.001

0.001 0.01 0.1 1

Pow

er S

pect

ral D

ensi

ty [H

z-1]

Frequency [Hz]

Band B (626.06 GHz)200911101346-200911121340

1.089 x 10-8 (1/f)1.592

ch.1296

B= 8 MHz

B= 64 MHz

The SMILES SIS re eiver shows very high sensitivity,meeting requirement with a margin.The noise level is one order of magnitude below the onventional submillimeter sounder in spa e.The stability time of the re eiver is about 8 s in spa e.


Antenna S an Pattern

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0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

1.6 1.8 2.0 2.2 2.4 2.6 2.8

Det

ecte

d P

ow

er

AOS Frequency [GHz]

Hot Calibration

Cold Calibration

Limb Observation

Tan

gent

Hei

ght

0 km

90 km

190 km

Hot CalibrationFreq. Calib.

53 sTyp

ical

Det

ecte

d P

ower

Cold Calibration

Limb Scanning

0

0.1

0.2

0.3

0.4

0.5

625.2 625.4 625.6 625.8 626 626.2

∆T [

K]

Frequency [GHz]

Band B AU2

Single channel with drift

Single channel without drift

64-MHz resolution with drift

SMILES repeats limb s annig, old alib.,freq. alib., and hot alib. every 53 s(horizontal sampling period: 360 km)Considerable long alibration period (53 s)has no impa t on spe tral ∆T (< 0.42 K).∆T for ontinuum signal is < 0.27 K.


Example of Observed Spe tra

0

50

100

150

200

250

Lim

b B

right

ness

[K

]

SMILES band C, 2010/01/28 09:44, 45.6E 65.4N, SZA=83.8o

ClO10.1 km12.2 km14.3 km

16.4 km

18.4 km

20.5 km

22.6 km24.6 km26.6 km

-2 0 2 4 6 8 10

649.2 649.4 649.6 649.8 650.0 650.2 650.4

Frequency [GHz]

18OOO

HO2

17OOO 28.6 km

30.6 km

44.7 km

0

50

100

150

200

250

Lim

b B

right

ness

[K

]

SMILES band B, 2010/01/27 09:21, 44.1E 64.9N, SZA=83.3o

O3 HCl

11.5 km

13.6 km

15.6 km

17.7 km

19.8 km21.8 km23.9 km

-2 0 2 4 6 8 10

625.2 625.4 625.6 625.8 626.0 626.2

Frequency [GHz]

18OOO O18OO

30.0 km

34.0 km

44.1 km

0

50

100

150

200

250

Lim

b B

right

ness

[K

]

SMILES band A, 2010/01/28 09:44, 45.6E 65.4N, SZA=83.8o

O3H37Cl

10.1 km12.2 km

14.3 km

16.4 km

18.4 km

20.5 km

22.6 km24.6 km

-2 0 2 4 6 8 10

624.4 624.6 624.8 625.0 625.2 625.4 625.6

Frequency [GHz]

O3,v1,3 O3,v2

28.6 km

30.6 km

44.7 km

Every 53 s, two of these three sets oflimb spe tra were observed.The spe tra have low ∆T and stablespe tral baselines.


Calibration of Observed Spe tra• Brightness intensity alibration

• Frequen y alibration

• Field-of-view alibration

T∆

f∆

z∆ISS

• Intensity-s ale alibration• Gain-nonlinearity orre tion• Frequen y-s ale alibration• Filter response pattern measurement• Tangent-height alibration• Beam-pattern measurement





T∆

f∆

z∆ISS

• Intensity-s ale alibration• Gain-nonlinearity orre tion• Frequen y-s ale alibration• Filter response pattern measurement• Tangent-height alibration• Beam-pattern measurement

(dis ussed in profile-validataion papers)→ IEEE JSTARS, 5(3), 2012.

See a Wednesday poster WEP.P.363.→ IEEE JSTARS, 5(3), 2012.

→ IEEE TAP, 60(8), 2012.Today's topi s





T∆

f∆

z∆ISS

• Intensity-s ale alibration

• Frequen y-s ale alibration

• Tangent-height alibration

WEP.P.363.

Today's topi s

Brightness resolution : <0.42 K (1.1 MHz resol.)→ Intensity s ale <1 % (∼2 K)Frequen y resolution : 1.1 MHz→ Frequen y s ale <10 kHz (relative)→ Frequen y s ale <100 kHz (absolute)Height resolution : ∼3 km→ Height s ale <50 m (relative)


ISS Attitude

2000 km

Tangent point

ISS Altitude: 333 - 370 km

SMILES observes limb emission in a tangent height rangebetween ∼0 and 100 km with a step of about 2 km.

We need to know the ISS attitude with enough pre isionfor the limb observation.Tangent-height pre ision ∼ 50 m→ Pointing pre ision needs to be less than 0.0014◦ (5 ar se )


Typi al ISS Attitude ISS orbit

Tangent point65 No

38 So

-5.6

-5.2

-4.8

-4.4

-1.2

-0.8

-0.4

0.0

0.4

15:00 15:15 15:30 15:45 16:00 16:15 16:30 16:45 17:00 17:15 17:30 17:45 18:00

Attitude by ISS GN and C, 2010/01/25

ISS

Att

itu

de

[d

eg]

Roll

Pitch

Yaw

3 hoursOrbit period length

1◦

ISS ir ulates around the Earth with a periodof about 91 min.The attitude varies almost periodi ally, butthe orbit-by-orbit variation is unpredi table.


Bending of ISS Stru ture

ISS GN&C

SMILESLimb viewing Photo ourtesyof

NASA

Mutual movement between SMILES and the ISS main body dependson the dire tion toward the sun. SMILES moves slowly relativeto the ISS main body with anamplitude of about 0.05◦ or less.


Vibration of ISS Stru tureISS GN&C

MAXI

SMILES Photo ourtesyofNASA

-1.184

-1.183

-1.182

-1.181

-1.180

-1.179

-1.178

-1.177

-1.176

-1.175

-1.174

16:16:00 16:16:30 16:17:00 16:17:30 16:18:00 16:18:30 16:19:00

ISS

Pit

ch [

deg

]

ISS attitude, 2010/01/25

Attitude by MAXI/R

LG

Attitude by ISS GN and C

In short time s ale, the attitude aroundSMILES moves by about 0.003◦ (peak-to-peak) o asionally.


Vibration of ISS Stru ture

2010/01/25 (GMT)

Fre

qu

ency

[H

z]

Vibration between MAXI/RLG and ISS/GNC [deg]

00:00 04:00 08:00 12:00 16:00 20:00 00:00

0.1

1

0.0000

0.0001

0.0002

0.0003

0.0004

0.0005

0.0006

0.0007

0.0008

0.01

A remarkable vibration around 0.25 − 0.3 Hz isobserved from 7:00 to 23:00 (GMT).This vibration is known as a resonant frequen y ofISS ex ited by a tivity of astronauts.

Color spe trogram of angular attitude differen e between ISS GN&C and MAXI.The olored value is an integration of vibration amplitude density over a third o tave.


Tangent Height Calibration

0

20

40

60

80

100

0 50 100 150 200 250

Tan

gent

Hei

ght [

km]

Limb Brightness [K]

• The tangent height an be retrievedfrom the spe tra.• The tangent height an be derivedfrom geometri al data.We dis uss here the geometri alderivation.


Geometri al Tangent Height Derivation

(1)

(3)

(4)

(2)

Tangent Height

Error sour es of geometri ally derived tangent height:(1) Offset of the submillimeter beam dire tion from a me hani al axis(stable systemati error)(2) Error in an en oder of the antenna elevation angle (∼0.0008◦)(3) Error of the position of ISS (basi ally negligible, ex ept the JEM's error)(4) Error of the attitude in inertial spa e


SMILES Star Sensor

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-0.35

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

16:46 16:48 16:50 16:52 16:54 16:56 16:58

Atti

tude

rel

ativ

e to

ISS

[deg

]

SMILES star sensor attitude, 2010/02/23

Cross axis (nadir)

Cross axis (orbit perp.)

Twist angle about boresight

SMILES dete ts the attitude with a star amera.

Bore dire tion of the star amera Submillimeter beam dire tionThe error in the star sensor of an axis around the amera bore (r.m.s. 0.017◦) propagates to the tangentheight error (r.m.s. 0.01◦ in elevation angle).


MAXI Ring Laser Gyros ope

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6

��

SMILESMAXI

The ring laser gyros ope (RLG) installed onthe Monitor of All-sky X-ray Image (MAXI)is used to determine the SMILES attitude.The tangent height is derived from an attitude that is based on the RLG dataand averagely aligned with the SMILES star-sensor attitude.RLG has an attitude pre ision ofabout 0.001◦ (rms).


Attitude based on the RLG Data

-0.160-0.150-0.140-0.130-0.120-0.110-0.100-0.090

16:12 16:13 16:14 16:15 16:16 16:17 16:18 16:19 16:20 16:21 16:222010/01/25 16:11:57 - 16:22:33

Z-a

xis

(ro

ll) [

deg

]

σ(starcamera-RLG)= 47.81’’ σ(RLG-ISS)= 15.56’’

-0.066-0.064-0.062-0.060-0.058-0.056-0.054

Y-a

xis

(-p

itch

) [d

eg]

σ(starcamera-RLG)= 2.47’’ σ(RLG-ISS)= 5.03’’-0.136-0.134-0.132-0.130-0.128-0.126-0.124

Attitude Differences

X-a

xis

(yaw

) [d

eg]

σ(starcamera-RLG)= 4.24’’ σ(RLG-ISS)= 10.00’’

SMILES/star camera - ISS/GNCMAXI/RLG - ISS/GNC

From the ring laser gyros ope (RLG) data, an attitude data is estimated so as to agreewith the star-sensor attitude averaged for SMILES s an period (53 s) in X and Y axes,and for longer time s ale (±3 min.) in Z axis.This alignment estimation gives an error of about 0.003◦.


Tangent Height Profile of a S an

-300

-200

-100

0

100

200

300

0 5 10 15 20 25 30 35

Time from the beginning of the scan [s]

Dif

fere

nce

fro

m t

he

qu

asi-

linea

r sc

an p

atte

rn [

m]

SMILES/star cameraISS/GNC

MAXI/RLG

0

50

100

150

200 SMILES scan at 2010/01/25 05:37:48

Tan

gen

t A

ltit

ud

e [k

m]


MAXI/RLG

-400

-300

-200

-100

0

100

200

0 5 10 15 20 25 30 35

Time from the beginning of the scan [s]

Dif

fere

nce

fro

m t

he

qu

asi-

linea

r sc

an p

atte

rn [

m]


MAXI/RLG

0

50

100

150

200 SMILES scan at 2010/01/25 16:17:22

Tan

gen

t A

ltit

ud

e [k

m]


MAXI/RLG

Nighttime Daytime

0.005◦

2◦

Tangent height is estimated from SMILES star sensor, ISS GN&C, and MAXI RLG.Offset (∼0.1◦) in ISS/GN&C tangent height is removed in the figures.


Tangent Height Profile of a S anThe standard deviation of the tangent-height mean offset,whi h is al ulated by retrieval pro ess from spe tra of a s an,is 0.14 km (0.0038◦ in elevation angle).That is onsistent with a root sum-square of:RLG-attitude standard deviation 0.001◦Error in estimation of the initial orientation for RLG 0.003◦En oder error of the antenna elevation angle 0.0008◦Error in al ulation of the tangent-height mean offset from spe tra 0.002◦The initial-orientation error (0.003◦) is the error in aligningthe RLG data with the SMILES star-sensor attitude.It will be redu ed in future improvement of the algorithm.

The relative error of the tangent heights in a s anis about 46 m (0.0013◦)Photo ourtesyofNASA


Summary• SMILES performan e and alibration

• Atmospheri limb was su essfully observed for 6 month withvery low noise and almost perfe t baseline feature• The spe tra are well- alibrated in intensity and frequen y s ales.

• ISS attitude• SMILES moves slowly relative to the ISS main body with 0.1◦ p-p.• JEM o asionally has a vibration of 0.003◦ p-p with a frequen yof about 0.25 Hz.

• SMILES tangent-height a ura y• The data from the ring laser gyro. of MAXI is used to al ulatetangent heights.• The error of the tangent height is about 46 m (0.0013◦) in a s an.• The standard deviation of the tangent-height offset error of ea hs an is less than 140 m (0.0038◦).

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