Inter-satellites radiometric calibration status of COSMO-SkyMed constellationsarcv.ceos.org/site_media/media/documents/04_CEOS2015... · 2015-12-15 · Inter-satellites radiometric

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Inter-satellites radiometric calibration status of COSMO-SkyMed constellation

CEOS SAR 2015 Valerio Grimani, Pasquale Salemme

2015, Thales Alenia Space

COSMO-SkyMed Overview

El Sosneado COSMO-SkyMed Campaign

Inter-satellites calibration assessment

Radiometric performances

Conclusions

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Summary

Unknown calibrators characterization by means of COSMO-SkyMed data


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COSMO-SkyMed overview

COSMO-SkyMed (Constellation of Small Satellites for Mediterranean basin Observation) is a 4-satellite constellation funded by ASI (Agenzia Spaziale Italiana) and Italian MoD.

The overall objective is the global Earth observation and the relevant data exploitation for the needs of the military community as well as for the civil community (Dual Use).

Thales Alenia Space Italia is the prime contractor of the end-to-end system and leads an industrial team of small and medium sized Italian companies including many from the Finmeccanica group, including Telespazio which is responsible for the Ground Segment design and development.


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The satellites were launched from the Vandenberg Air Force base in California, on board a Boeing Delta II launchers. 4 satellites equipped with High resolution, X-band imaging radar (SAR) with > 2 x 650 km ground access Sun-synchronous orbit for satellites operation maximization @620 km altitude Global Earth access (including polar caps) with all weather / night-daylight sensing capability

7th June 2007

8th December 2007

24th October 2008

6th November 2010


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SPOTLIGHT 1m Resolution (10km x 10 km)

HIMAGE 3 m x 3 m Resolution

(40km x 40 km) PINGPONG

15 m x 15 m Resolution (30 km x 30 km)

WIDEREGION 30 m x 30 m Resolution

(100 km x 100 km) HUGEREGION

100 m x 100 m Resolution (200 km x 200 km)

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Courtesy of ASI, All rights reserved

SCANSAR (medium to coarse resolution over large swath)


STRIPMAP (high to medium resolution over tenth of km images)


SPOTLIGHT (high resolutions over small images)


Scope: to trace a state of current radiometric performances proposing an inter-satellites calibration report among the four SAR sensors

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Scope: to trace a state of current radiometric performances proposing an inter-satellites calibration report among the four SAR sensors

Action: El Sosneado (Mendoza, Argentina) site campaign:

12 trihedral corner reflectors deployed in not sensitive sites, outside the Italian country Not impacts on usability of the system by users Entire COSMO-SkyMed constellation used Different SAR modes Different access angles Large amount of data collection

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HIMAGE mode: inter-satellites calibration performances


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HIMAGE VV mode: inter-satellites calibration performances

CSK HIMAGE VV RCS std 0.09 dB }

RCS statistics: COSMO-SkyMed 1 mean : 47.60 dBm2 COSMO-SkyMed 2 mean : 47.63 dBm2 COSMO-SkyMed 3 mean : 47.69 dBm2 COSMO-SkyMed 4 mean : 47.45 dBm2


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HIMAGE HH mode: inter-satellites calibration performances

CSK HIMAGE HH RCS std 0.11 dB }



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SPOTLIGHT mode: inter-satellites calibration performances


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SPOTLIGHT VV mode: inter-satellites calibration performances

CSK SPOTLIGHT VV RCS std 0.23 dB }



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SPOTLIGHT HH mode: inter-satellites calibration performances

CSK SPOTLIGHT HH RCS std 0.13 dB }



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PINGPONG mode: inter-satellites calibration performances


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PINGPONG VV mode: inter-satellites calibration performances

CSK PINGPONG VV RCS std 0.08 dB }



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PINGPONG HH mode: inter-satellites calibration performances

CSK PINGPONG HH RCS std 0.12 dB }



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SCANSAR mode: inter-satellites calibration performances


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SCANSAR WR VV mode: inter-satellites calibration performances

CSK SCANSAR WR VV RCS std 0.23 dB }



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SCANSAR WR HH mode: inter-satellites calibration performances

CSK SCANSAR WR HH RCS std 0.27 dB }



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Trihedral corner reflector EM model

RCS expected values w.r.t. angle on corner evaluated by using data provided by CONAE:

TCR Elevation = 43.53° RCS peak ~47.7 dBm2 @ ~35°


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COSMO-SkyMed RCS VV Measurements v.s. TCR EM model

COSMO-SkyMed radiometric accuracy requirement of 1 dB RCS measurements:

CSK HIMAGE radiometric accuracy: 0.14 dB (17 products)


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CSK HIMAGE radiometric accuracy: 0.14 dB (17 products) CSK SPOTLIGHT radiometric accuracy: 0.29 dB (15 products)


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CSK HIMAGE radiometric accuracy: 0.14 dB (17 products) CSK SPOTLIGHT radiometric accuracy: 0.29 dB (15 products) CSK PINGPONG radiometric accuracy: 0.18 dB (12 products)


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CSK HIMAGE radiometric accuracy: 0.14 dB (17 products) CSK SPOTLIGHT radiometric accuracy: 0.29 dB (15 products) CSK PINGPONG radiometric accuracy: 0.18 dB (12 products) CSK SCANSAR WR radiometric accuracy: 0.24 dB (23 products)


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COSMO-SkyMed RCS HH Measurements v.s. TCR EM model


CSK HIMAGE radiometric accuracy: 0.15 dB (27 products)


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CSK HIMAGE radiometric accuracy: 0.15 dB (27 products) CSK SPOTLIGHT radiometric accuracy: 0.28 dB (18 products)


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CSK HIMAGE radiometric accuracy: 0.15 dB (27 products) CSK SPOTLIGHT radiometric accuracy: 0.28 dB (18 products) CSK PINGPONG radiometric accuracy: 0.41 dB (15 products)


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CSK HIMAGE radiometric accuracy: 0.15 dB (27 products) CSK SPOTLIGHT radiometric accuracy: 0.28 dB (18 products) CSK PINGPONG radiometric accuracy: 0.41 dB (15 products) CSK SCANSAR WR radiometric accuracy: 0.34 dB (21 products)


29 COSMO-SkyMed HIMAGE mode products over permanent scatterers Four opportunity targets of the same scene have been considered

Opportunity Targets: inter-satellites calibration performances

COSMO SkyMed - 1




COSMO SkyMed - 2




COSMO SkyMed - 3




COSMO SkyMed - 4




CSK std 0.19 dB

CSK std 0.12 dB

CSK std 0.24 dB

CSK std 0.12 dB


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Conclusion & Acknowledgements

Based on data acquired with a dedicated campaign on well-known calibration sites, the RCS measurements obtained with the four Satellites of COSMO-SkyMed constellation demonstrate the alignment of values measured by varying the SAR sensors and acquisition geometries.

The achieved inter-satellites radiometric alignment during the commissioning phases of the four satellites of the constellation can be then considered fully preserved.

Even though three satellites are beyond their expected end of life, the constellation can be considered still fully operative and calibrated.

The data used in this assessment are only a subset of a campaign that has lasted more than three years and that is still on going, being part of COSMO-SkyMed performances monitoring. A special thanks to ASI and CONAE for the availability of data and calibration site.


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Thank you for your attention!

ESTEC - Noordwijk, Netherlands COSMO-SkyMed Spotlight Product – Processed by Thales Alenia Space

Documents

Inter-satellites radiometric calibration status of COSMO-SkyMed constellationsarcv.ceos.org/site_media/media/documents/04_CEOS2015... · 2015-12-15 · Inter-satellites radiometric