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ASAR IMS & WVI Products quality Introduction

ASAR IMS & WVI Products quality Introduction. IMS Product characteristics Product quality and absolute calibration results WVI Product charactersitics Product quality and absolute clibration. B. Rosich ESA,ESRIN. 1751, IS1. 1758, IS7. ASAR IMS Product charateristics (I).

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ASAR IMS & WVI Products quality Introduction

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  1. ASAR IMS & WVI Products quality Introduction • IMS Product characteristics • Product quality and absolute calibration results • WVI Product charactersitics • Product quality and absolute clibration B. Rosich ESA,ESRIN

  2. 1751, IS1 1758, IS7 ASAR IMS Product charateristics (I) • Slant range, single look complex image. • Single polarisation VV or HH. Multiple incidence angles (IS1 to IS7). Coverage from 100 Km to 56 km • Natural pixel spacing in range and azimuth. Azimuth resolution from 4 m to 5 m. Range resolution from 9 m to 18 m due to decreasing chirp bandwidth.

  3. 1751, IS1 1758, IS7 ASAR IMS Product charateristics (II) • Elevation antenna pattern correction not applied. Range spreading loss correction not applied. • Hamming window with a=0.75 applied in azimuth and range • Processing algorithm: Range Doppler. Phase preserving.

  4. Range Azimuth Range Azimuth ASAR IMS IRF analysis (VV, all beams) IS1, 1751, edam IS7,1758, edam IRF analysis based on the ASAR and Radarsat transponders

  5. ASAR IMS IRF analysis (VV, all beams) All IRF quality parameters are well within the requirements for all beams

  6. ASAR IMS absolute calibration (VV, all beams) • Absolute calibration constant derived for all beams. • Prelimimary results indicate a very similar K for all beams. More measurements are required particularly in IS2, IS5 and IS6.

  7. ASAR IMS Azimuth ambiguity (VV, all beams) • Azimuth PT ambiguity are be observed particularly for the Edam transponder as the ambiguous response falls onto the sea area. • Average PT azimuth ambiguity ratio: -26.7 dB < Requirement: –25 dB 756, Edam,, early and late azimuth ambiguities

  8. 670, extracted, aalsmeer Extracted / Nominal Chirp processing • Very little difference in IRF parameters processing with extracted and nominal chirp 670, nominal, aalsmeer

  9. ASAR IMS Localisation accuracy • Preliminary results of localisation accuracy derived using restituted orbits. • Range location error increases after the correction of the small echo shift problem (13 June). • Processing with nominal chirp confirms that most of the error is due to the chirp offset. • Mean azimuth location error of 9 samples, i.e. between 30 m (IS3,IS5, IS7) and 36 m (I61,IS2,IS3, IS4, IS6)

  10. ASAR IMS Product verification Conclusions • Product quality is within the requirements • Processing will be switched to NOMINAL chirp systematically • Preliminary calibration constant value determined for all the beams. Final value to be refined with more data.

  11. ASAR WVI Product charateristics (I) • Slant range, single look complex image. The product includes also the Cross Spectra for each imagette. • Natural pixel spacing in range and azimuth. Azimuth resolution from 4 m to 5 m. Range resolution from 9 m to 18 m due to decreasing chirp bandwidth. • Elevation antenna pattern correction not applied. Range spreading loss correction not applied. • Up to 400 imagettes per product • Systematically acquired & processed over the ocean. • WVI/WVS products are used for around orbit verification of key instrument parameters

  12. IS2 IS1 IS2 IS1 IS2 IS1 ASAR WVI Product charateristics (II) • Single polarisation VV or HH. Multiple incidence angles (IS1 to IS7). • One product may contain imagettes from 1 beam or from 2 alternating beams

  13. WVI Calibration over the ASAR Transponders • Imagette verification is mainly based on measurements over the transponder and rain forest. • WVI IRF parameters are well within the quality requirements

  14. WVI Calibration over the Amazon Rain Forest • One orbit available over the Rain Forest: IS/IS2 (1782) • Derived Sigma0 used to calibrate the WVI products together with the transponder measurements IS1 IS2

  15. ASAR WVI Product verification Conclusions • Product quality is within the requirements • Preliminary calibration constant value derived for IS2 over 1 ASAR transponder and the rain forest. Good agreement of the results.

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