rfi in the radiometric calibration data yuji taniguchi ( m itsubishi s pace s oftware co.,ltd.)

AMSR-E Science meeting 03/June/2010

1

Mitsubishi Space Software CO.,LTD.

RFI in the radiometric calibration data

Yuji Taniguchi (Mitsubishi Space Software Co.,Ltd.)

Akira Shibata （ Japan Aerospace Exploration Agency)

AMSR-E Science meeting, 03/June/2010, Huntsville

DD8040-10-AMSR001


2


Increase of irregular count value of AMSR-E calibration sources; Cold Sky Mirror Count and Hot Load Count.Radio-Frequency interference(RFI) might cause the increment.

1. Preface


3


2. Influence of RFI to calibration sources

Irregular points detection using standard deviation.Convert the calibration source count to the voltage.Calculate standard deviation using 8 points in the scan azimuth direction, 11 lines in the along track direction. Easier to detect anomaly.

alongtrack

direction

scan azimuth direction

11scan

8 points near the center

2.4

2.45

2.5

2.55

2.6

2.65

1 201 401 601 801 1001 1201 1401 1601 1801走査番号

[mV]

電圧

値

0

0.05

0.1

0.15

0.2

標準

偏差

CSM 平均値標準偏差

1/Nov/2008 Path146 　 Descending6.9GHz 　 Cold Sky Mirror Count

Standard deviation

CSM Count

Unusual rises are detected

Voltage [m

V]

Standard deviation [m

V]

Scan Number


4


2 Influence of RFI to calibration sources （ Time 　 series ）Occurrence timing of RFIInvestigate level 1 products observed from June 2002 to December 2009.Plot the maximum standard deviation for each products as shown below

200736.5GHz V-pol.

AscendingCold Sky Mirror

Reflection of the moonThis effect is already known.We neglected it and focus on the other anomalies.

Standard deviation [m

V]

Date（ 1 year)

１ /Jan. 3 １ /Dec.


5


6.9GHz

- Cold Sky Mirror Count -


6


Ascending Descending

2002

2003

2004

2005

2006

2007

2008

2009

2002

2003

2004

2005

2006

2007

2008

2009

2.1 Influence of RFI to calibration sources （ Time 　 series ）　 Cold Sky Mirror Count 6.9GHz 　 V-pol (x-axis ： date ）

The RFI has always occurred.Where do these occur?

We estimated the sub-satellite point.


7


6.9GHz 　 Vpol 　 Descending 6.9GHz 　 Hpol 　 Descending

6.9GHz 　 Vpol 　 Ascending 6.9GHz 　 Hpol 　 AscendingYearly Maximum value of standard deviation(2008)

2.1 Specify the area of interference source　 Cold Sky Mirror Count 　 6.9GHz

・ RFI 　 occurs in the specific land areas.


8


-1770

-1760

-1750

-1740

-1730

-1720

-1710

-1700

-1690

1 201 401 601 801 1001 1201 1401 1601 1801Scan Number

Cold

Sky M

irror

Coun

t (av

erag

e)

CSM 06V45Count≒4.5K

18/Aug./2003 Path 185 Descending

This effect is removedat the Level 1B brightness temperature.

Europe


9


10.7GHz



10



2002

2003

2004

2005

2006

2007

2008

2009

2002

2003

2004

2005

2006

2007

2008

2009

Since July 2007


Unusual rises


11




2.2 Specify the area of interference source　 Cold Sky Mirror Count 10.7GH ｚ

RFI was detected in the East Coast(U.S.) sometime West Coast(U.S.) Europe

Since July 2007


12


-420

-415

-410

-405

-400

-395

-390

-385

-380

1 201 401 601 801 1001 1201 1401 1601 1801Scan Number

Cold

Sky M

irror

Cou

nt(av

erag

e)

CSM 10V

6Count≒2.4K

02/Dec./2008 Path 91 Ascending

U.S. East Coast This effect is removedat the Level 1B brightness temperature.


13


18.7GHz



14



2002

2003

2004

2005

2006

2007

2008

2009

2002

2003

2004

2005

2006

2007

2008

2009

Since September 2007


Reflection of the moon

Unusual rises


15



18.7GHz 　 Vpol 　 Ascending 18.7GHz 　 Hpol 　 AscendingMonthly Maximum value of standard deviation(Feb./2008)

2.3 Specify the area of interference source　 Cold Sky Mirror Count 18.7GH ｚ

RFI was detected the specific area:・ The north side of the Hawaii・ Near the Antarctic Peninsula

Reflection of the moonReflection of the moon

Since Feb. 2008.

Since Sep. 2007.


16


-392

-390

-388

-386

-384

-382

-380

1 201 401 601 801 1001 1201 1401 1601 1801Scan Number

CSM

18V

- 416

-415

-414

-413

-412

-411

-410

CSM

18H

CSM 18VCSM 18H

6Count≒2.4K2Count≒0.8K

2Count≒0.8K

07/Oct./2009 Path 167 Ascending

The north side of the HawaiiThis effect is not removedat the Level 1B brightness temperature.


17


6.9GHz

- Hot Load Count-


18



2002

2003

2004

2005

2006

2007

2008

2009

2002

2003

2004

2005

2006

2007

2008

2009

2.1 Influence of RFI to calibration sources （ Time 　 series ）　 Hot Load Count 6.9GHz 　 V-pol (x-axis ： date ）

The RFI has always occurred.


19




2.2 Specify the area of interference source　 Hot Load Count 　 6.9GHz

RFI was detected the specific area:　 Europe China(East) U.S


20


1360

1380

1400

1420

1440

1460

1480

1500

1520

1 201 401 601 801 1001 1201 1401 1601 1801Scan Number

Hot L

oac C

ount

(aver

age)

06V06H

18Count≒1.8K12Count≒1.2K

16/May/2008 Path 35 Ascending

This effect is not removedat the Level 1B brightness temperature.

Europe


21


10.7GHz

- Hot Load Count -


22



2002

2003

2004

2005

2006

2007

2008

2009

2002

2003

2004

2005

2006

2007

2008

2009


The RFI has often occurred.


23


10.7GHz 　 Hpol 　 Descending

10.7GHz 　 Hpol 　 Ascending

2.2 Specify the area of interference source　 Hot Load Count 10.7GHz

10.7GHz 　 Vpol 　 Descending

10.7GHz 　 Vpol 　 AscendingYearly Maximum value of standard deviation(2005)

RFI was detected the specific area:　 Europe West Coast(U.S.)


24


310

315

320

325

330

335

340

345

350

355

360

1 201 401 601 801 1001 1201 1401 1601 1801Scan Number

Hot L

oad C

ount

10V(

aver

age)

320

325

330

335

340

345

350

355

360

Hot L

oad C

ount

10H(

aver

age)

10V10H

19/Oct./2005 Path 15 Ascending

2count≒0.8K

8Count≒3.2K


Europe


25


18.7GHz

- Hot Load Count -


26



2002

2003

2004

2005

2006

2007

2008

2009

2002

2003

2004

2005

2006

2007

2008

2009


The RFI has few occurred.


27




2.2 Specify the area of interference source　 Hot Load Count 18.7GHz

RFI was detected the specific area: East Coast(U.S.)


28


315

320

325

330

335

340

345

350

355

1 201 401 601 801 1001 1201 1401 1601 1801Scan Number

Hot L

oad C

ount

18V(

aver

age)

340

345

350

355

360

365

370

375

380

Hot L

oad C

ount

18H(

aver

age)

18V18H7Count≒2.8K

8Count≒3.2K

27/Jan./2004 Path 110 Ascending


East Coast(U.S.)


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RFI has occurred almost in the same position.These sources are possibly the communication between the ground and the geostationary satellites.

2.2 Specify the area of interference source


30


We examined 6.9GH ｚ Cold Sky Mirror Count more in detail.Change the scale factor to emphasize the anomalies as shown below:

Monthly MAP (March 2009 Descending)

3 RFI from LEO’s　


31


A very small amount of RFI occurs. Monthly MAP (March 2009 Descending)


Scale Change


32


To investigate the relationship between observation date and RFI generation, we made images of standard deviation of Cold Sky Mirror shown like below:


Periodic cycle

Standard　 deviation

0.00

0.01

11/Apr/2011Path 189

26/Apr/2011Path 173

North Pol.

South Pol.

time series

This RFI occurs periodic cycle with time.

alongtrack

direction

Focus on


33



6Path6Path6Path6Path6Path6Path

(No.1)

(No.2)

(No.3)

(No.4)

(No.5)

(No.6)(No.7) RFI occurred each 6 orbit

cycle.


34


-1780

-1770

-1760

-1750

-1740

-1730

1 201 401 601 801 1001 1201 1401 1601 1801Scan Number

Cold

Sky M

irror

Cou

nt(av

erag

e)

06V06H

15Count≒1.5K

15Count≒1.5K

13/Apr./2010 Path 219 Descending

RFI effect (No.2)

We identified the locations of each RFI occurrence which will be shown the following slides.


35


Site of RFI occurrence(No.1)

12/Apr.P123

3 RFI from LEO’s　 Sites of RFI occurrence 　


36



13/Apr.P219

12/Apr.P123



37



13/Apr.P219

12/Apr.P123

13/Apr.P082



38



13/Apr.P219

12/Apr.P123

13/Apr.P082

13/Apr.P178



39



13/Apr.P219

12/Apr.P123

13/Apr.P082

13/Apr.P178

14/Apr.P041



40



13/Apr.P219

12/Apr.P123

13/Apr.P082

13/Apr.P178

14/Apr.P041

14/Apr.P137



41


13/Apr.P219

12/Apr.P123

13/Apr.P082

13/Apr.P178

14/Apr.P041

14/Apr.P137

15/Apr.P233

Area of RFI sites are move The cause of RFI is not the communications between the geostationary satellites and the ground. Periodic cycle Effect of LEOs?




42


Ocean products retrieved from 6.9GHz, such as SST and SSW, are damaged seriously by RFI.(Sep.2005 Yoshikawa@MSS)

This RFI source is the Globalstar downlink beam.

3 RFI from LEO’s　 Which satellite is the source of RFI?


43


6.9GHz RFI in Cold Sky Mirror

Globalstar

1400km112min

Aqua/AMSR-E

705km100min

CSM 　 Viewingfield

Beacon(6.85GHz)

We think that the satellite electric wave mixed with the view of Cold Sky Mirror.Globalstar send out beacon of 6.85GHz.We investigated the positional relation between Globalstar and Aqua.

3 RFI from LEO’s　 Which satellite is the source of RFI?


44


Focus on GLOBALSTAR 54

AQUA

Site of RFI occurrence(No.1) 12/April/2010 18:46:10

12/Apr.P123

3 RFI from LEO’s　 Positional relation between Aqua and Globalstar


45


GLOBALSTAR 54

AQUA


12/Apr.P123



46


GLOBALSTAR 54


15/Apr.P233


AQUA


47


GLOBALSTAR 54


13/Apr.P082


AQUA


48


GLOBALSTAR 54


13/Apr.P178



49


GLOBALSTAR 54


14/Apr.P041



50


GLOBALSTAR 54


14/Apr.P137



51


GLOBALSTAR 54


15/Apr.P233


Positional relations between Globalstar54 and Aqua are the same in all cases.


52


RFI from the specific areasRFI has occurred the radiometric calibration sources in 6.9GHz,10.7GHz and 18.7GHz.The source is possibly the communication between the ground and the geostationary satellites.

RFI from LEOIn the Cold Sky Mirror Count of 6.9GHz, RFI occurs periodic cycle, which are probably caused by Globalstar.

4.Summary


53



54


Influence of RFI to Cold Sky Mirror •6.9GHz, the RFI has always occurred.•10.7GHz, the RFI has occurred at ascending products since Jun. 2007. •18.7GHz, the RFI has occurred at ascending products since Sep. 2007. And, the RFI has occurred at descending products since Feb. 2008.

Periodical change of RFI?Where do these occur?


55


Reflection of the moon

alongtrack

direction

6.9GHz10.7GHz18.7GHz23.6GHz36.5GHz 89.0GHz

V H V H V H V H V H V H V HAhorn Bhorn

Cold Sky Mirror Count

little

big

Cold Sky Mirror Count


56


2.2 Specify the area of interference source

lat. and lon. ofthe ground observation position

lat. and lon. ofthe sub-satellite position

satellite

About 3min.120scan

To locate the source of RFI, we estimated the latitude and longitude of the sub-satellite points from the ground observation points.Distances between the ground observation points and the sub-satellite points are nearly equivalent to 120 lines which corresponds to 3 minutes.We estimated the sub-satellite position using the above relationship and equidistant cylindrical projection to calculate standard deviations.


57


-424

-422

-420

-418

-416

-414

-412

1 201 401 601 801 1001 1201 1401 1601 1801Scan Number

CSM

18V

- 435.0

-434.5

-434.0

-433.5

-433.0

-432.5

-432.0

-431.5

-431.0

CSM

18H

CSM 18VCSM 18H

0.6Count≒0.24K

1.3Count≒0.5K

13/Jun./2009 Path 219 Descending

Near the Antarctic Peninsula This effect is not removedat the Level 1B brightness temperature.


58



2002

2003

2004

2005

2006

2007

2008

2009

2002

2003

2004

2005

2006

2007

2008

2009

Since September 2007

Since February 2008

2.1 Influence of calibration sources （ Time 　 series ）　 Cold Sky Mirror Count 18.7GHz 　 H-pol (x-axis ： date ）

Unusual rises

Unusual rises


59


１ scene

Observation　 date

Plot 　 the standard 　 deviation

To investigate the relationship between observation date and RFI generation, we made images of standard deviation of Cold Sky Mirror shown like below:


North Pol.

South Pol.


60


11/AprPath 189

26/AprPath 173

North Pol.

South Pol.0.00

0.01

Standard　 deviation

6.9GHz 　 VpolDescending

standard 　 deviation


rfi in the radiometric calibration data yuji taniguchi ( m itsubishi s pace s oftware co.,ltd.)

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