Page 1 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 ASAR Validation Review AP and GM Level 0 Product Quality Birgit Schättler Remote Sensing Technology Institute German Aerospace Center (DLR)

Page 2 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Objectives and Approach Downlink Data Quality Echo Data Statistics Detailed Analysis of an AP Level 0 Product Detailed Analysis of a GM Level 0 Product Summary and Conclusions Overview

Page 3 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Objectives ensure, that ASAR AP and GM level 0 products do not show systematic deficiencies start the quantitative analysis of raw data parameters like echo data statistics, noise measurements, …

Page 4 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Approach Evaluate systematically and automatically level 1B product annotation parameters related to level 0 product quality (e.g. downlink data quality, echo data statistics, noise measurements ) using a tool incorporated into the PDS functionality not yet available => only restricted systematic analysis possibilities based on CBTS (“Chris Buck Tool Set”) Perform a detailed analysis of selected level 0 products using SARCON, an off-line SAR product quality analysis software

Page 5 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 AP Systematic Analysis AP systematic analysis based on annotations of 106 products only : 57 APM, 49 APP 18 IS 1 : 1 VH8 VV VH9 HV HH, 24 IS 2 : 3 HH13 VV VH5 HV HH3 VV HH 8 IS 3 : 2 VH6 VV VH 22 IS 4 : 2 VH4 HH8 VV VH8 HV HH 16 IS 5 : 2 VH6 VV VH8 HV HH 8 IS 6 : 5 VV VH3 HV HH 10 IS 7 :3 VV VH7 HV HH

Page 6 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 AP Downlink Data Quality Summary missing range lines detected in 3 products: 1 with 7 missing, 2 with 1 missing each product with 7 missing range lines has 2 corrupted auxiliary codes, all other products show no auxiliary code error at all missing lines percentage = % (9 missing out of )  Good downlink data quality can be assumed

Page 7 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 I and Q Channel Bias

Page 8 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 I / Q Channel Standard Deviation

Page 9 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Noise Power Correction Factor

Page 10 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Detailed Analysis of an AP IS 2 Product ASA_APH_0PNPDK _094707_ _00022_03583_0043.N1 Netherlands calibration site with transponders in H/V and H/H polarisation, beam IS 6 “nominal timeline anomaly” no anomalies observed

Page 11 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Downlink Data Quality no missing / erroneous ISPs no missing range lines no errors in analysed auxiliary codes  perfect downlink data quality

Page 12 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 AP Timeline (Initial Cycle) initial noise : 8 lines in HV and 8 lines in HH initial calibration sequence : 97 pulses in HV and 97 pulses in HH pre-flight observed anomaly in periodic cycle is now the nominal case handled by PF_ASAR  timeline according to expectation

Page 13 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 AP Timeline (Periodic Cycles) pre-flight observed 237 echo + 1 cal in HV 237 echoin HH 237 echoin HV 238 echoin HH echoin HV 237 echo + 1 cal in HH 238 echoin HV 238 echoin HH echo + 1 cal in HV 237 echoin HH 237 echoin HV 238 echoin HH specified 237 echo + 1 cal in HV 238 echo in HH 238 echo in HV 238 echo in HH echoin HV 237 echo + 1 cal in HH 238 echoin HV 238 echoin HH echo + 1 cal in HV 238 echoin HH 238 echoin HV 238 echoin HH

Page 14 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Echo Data Histograms and Statistics HH polarisation I Bias = Q Bias = I Stddev = Q Stddev = IQ Gain imbalance = IQ Non-orthogonality = HV polarisation I Bias = Q Bias = I Stddev = Q Stddev = IQ Gain imbalance = IQ Non-orthogonality = I channel Q channel I channel Q channel no echo data saturation dynamic range not fully used

Page 15 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Echo Data Visual Inspection no anomalies observed HH HV

Page 16 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Range-Compressed Data Visual Inspection HHHV no anomalies observed

Page 17 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Detailed Analysis of a GM Product ASA_GM__0PNPDK _071147_ _00135_03696_0211 in VV polarization region in the north of Russia anomaly observed with instrument characterization file : wrong subsampling factors for beam SS2 … SS5 corrected INS file delivered by ESRIN

Page 18 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 GM1 Product

Page 19 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Downlink Data Quality no missing or erroneous source packet no single error in analysed auxiliary codes (PRI, SWST, SWL, up/down converter, TX pulse length, TX pulse bandwidth, resampling factor)  perfect downlink data quality

Page 20 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Echo Data Histogram no echo data saturation dynamic range not fully used Q I SS1SS5

Page 21 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Echo Data Statistics swath SS1: I Bias= , Q Bias= I Stddev= , Q Stddev= IQ Gain imbalance = , IQ Non-orthogonality = swath SS5: I Bias= , Q Bias= I Stddev= , Q Stddev= IQ Gain imbalance= , IQ Non-orthogonality =

Page 22 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Echo Data Visual Inspection SS1

Page 23 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Range-Compressed Data Visual Inspection SS1

Page 24 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Initial Calibration Pulses SS1 P1P1A P3P2

Page 25 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Periodic Calibration Pulses SS1 P1P1AP3P2

Page 26 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Summary and Conclusions (I) Analysed AP and GM level 0 products show a good overall product quality. First AP quantitative measurement results could be obtained, but based on a small variety of products only Only one GM product available

Page 27 ENVISAT Validation Workshop - ESRIN – 9-13 December 2002 Summary and Conclusions (II) Detailed analysis of selected level 0 products will be done only for “suspicious” products in the future The operational PDS tool for a systematic and automatic parameter evaluation is urgently needed -as indicator for possible anomalies -for further overall quality assessment -for further quantitative measurements