THE NEW ESA ERS SAR PRODUCTS

Transcription

1 fd D O C U M E N T document title/ titre du document THE NEW ESA ERS SAR PRODUCTS REPLACEMENT OF THE VMP BY THE PGS-ERS PROCESSOR prepared by/préparé par EOP-GOQ reference/réference ERSE-GSEV-EOPG-TN iue/édition 1 reviion/réviion 0 date of iue/date d édition tatu/état Approved Document type/type de document Technical Note Ditribution/ditribution a

2 The new ERS SAR Product iue 1 reviion 0 - page ii of iii Title titre The new ERS SAR Product - Replacement of the VMP by the PGS- ERS iue iue 1 reviion reviion 0 Author auteur C. Santella \, N. Miranda, B.Roich, P. Meadow, A. Monti-Guarnieri date date CHANGE LOG reaon for change /raion du changement iue/iue reviion/reviion date/date CHANGE RECORD Iue: 1 Reviion: 0 reaon for change/raion du changement page()/page() paragraph()/paragraph()

3 The new ERS SAR Product iue 1 reviion 0 - page iii of iii T A B L E A B L E O F C O N T E N T S O N T E N T S 1 INTRODUCTION Background Definition, acronym and abbreviation Reference document ERS-PGS SAR PRODUCTS VERSUS ERS SAR VMP PRODUCTS Naming convention for ERS-PGS product in ENVISAT format VMP AND ERS-PGS CEOS FORMAT COMPARISON General tructure Format difference for CEOS SAR RAW product Format difference for CEOS SAR SLC product Format difference for CEOS SAR PRI product CROSS-PROCESSOR INTERFEROMETRY Reference tet Baeline characteritic Coherence characteritic Phae difference characteritic InSAR cro-proceor tet Baeline characteritic Coherence characteritic Phae difference characteritic Cro-proceor phae preervation tet Baeline characteritic Coherence characteritic Phae difference characteritic...21

4 The new ERS SAR Product iue 1 reviion 0 - page 1 of 3 1 INTRODUCTION 1.1 Background The VMP proceor ha been ued by ESA to generate tandard SAR product in CEOS format ( for both ERS-1/2 miion ince the ERS-1 launch. ENVISAT ASAR data i being proceed by ESA uing the PF-ASAR proceor and ASAR product are delivered to uer in the ENVISAT format ( The ame proceing facility ha been tailored to the ERS SAR data characteritic and it ha been extenively ued for the pre-launch and pot-launch ASAR data verification activitie. In order to offer a uniform family of ESA SAR product to the uer, both in term of product characteritic, algorithm ued and final formatting, it ha been decided to ue the ame core proceor both for ASAR and for ERS data. The ESA VMP proceor will therefore be replaced by the ERS PGS ytem, which ue the ame core proceor a PF-ASAR and which i able to generate ERS SAR product both in ENVISAT and in CEOS format (enuring continuity with VMP product). Uing the new ERS PGS ytem it will be poible to provide uer with an extended family of ERS SAR product, imilar to the et of product available for ASAR Image Mode data. A table howing the ERS PGS product and format i provided in Chapter 2. Although the ERS-PGS ytem will be able to provide ERS SAR product equivalent to thoe that were available from the VMP proceor, it hall be treed that CEOS SAR product from both proceor will how ome minor difference in term of formatting and product characteritic. Thee difference are decribed in Chapter 2and 3. The cope of thi note i to preent the new et of ERS SAR product available from the PGS-ERS ytem and to provide a complete overview of difference between the new ERS SAR product and the VMP one. The ERS-PGS ytem i being ued pre-operationally ince early 2005 and it i planned to progreively replace the VMP proceor by the new ytem. During the tranition period, uer might receive ERS SAR product from any of the proceor. For product generated by the ERS-PGS cae, it will be poible for the uer to chooe between the CEOS and the ENVISAT format. It i expected that uer might need to combine product generated from the VMP proceor in the pat with the new ERS-PGS product. Combining the data from the two different ytem might be an iue only for InSAR related application. An aement of the implication i preented in Chapter 4.

5 The new ERS SAR Product iue 1 reviion 0 - page 2 of Definition, acronym and abbreviation ASAR BEST CEOS GEC IMP IMS IMG IMM PF-ASAR PGS-ERS PGS PRI SAR SLC VMP Advanced Synthetic Aperture Radar Baic ENVISAT SAR Toolbox Committee on Earth Obervation Satellite Geocoded Ellipoid Corrected image Image Mode Preciion image Image Mode Single-look complex image Image Mode ellipoid Geocoded Image Image Mode Medium reolution image Proceing Facility ASAR Proceing Facility ERS SAR Product Generation Sytem PReciion Image Synthetic Aperture Radar Single Look Complex image Verification Mode Proceor 1.3 Reference document R-1 ENVISAT-1 Product pecification. Volume 5: Product tructure, PO-RS-MDA-GS-2009 R-2 ENVISAT-1 Product pecification. Volume 8: ASAR Product Specification, PO-RS-MDA-GS- 2009, I.4,Rev.A, 11/05/04, R-3 ERS VMP RAW CEOS Format, Annex A, ERS SAR.RAW CCT and EXABYTE, ER-IS-EPO , R-4 ERS VMP SLC CEOS Format, Annex C, ERS SAR.SLC/SLC-I CCT and EXABYTE, ER-IS-EPO , R-5 ERS VMP PRI CEOS Format, Annex D, ERS SAR.RAW CCT and EXABYTE, ER-IS-EPO ,

6 The new ERS SAR Product iue 1 reviion 0 - page 3 of 3 2 ERS-PGS SAR PRODUCTS VERSUS ERS SAR VMP PRODUCTS The complete lit of product available from the PGS-ERS ytem i preented in Table 1. The table indicate a well per each product type: - Whether it wa available from the VMP and the correponding product name. - The product format. - Thoe product characteritic that will be different between VMP and PGS-ERS product. It i not intended here to provide a complete product characteritic decription but only to highlight the main proceing parameter that will change from one facility to the other. It hall be noted that for PGS-ERS product where both CEOS and ENVISAT format are available, only the product format i different but the data content i exactly the ame. ERS-PGS product in ENVISAT format follow the ame format pecification a the ENVISAT ASAR product and they can be read uing tandard ENVISAT reading tool uch a EnviView. ERS-PGS product in CEOS format follow baically the ame format pecification a the VMP CEOS product with ome minor difference (ee Chapter 3 and 4). Thee product can be read with tandard ESA tool uch a BEST.

7 The new ERS SAR Product iue 1 reviion 0 - page 1 of 1 Product Type Proceing facility Product name Formatting Level 0 Single Look Complex Image Preciion Image Geocoded Image Medium Rerolution Image Number of Look (Az*Rg) Total Azimuth BW [MHz] Azimuth Look BW [MHz] Ellipoid VMP RAW CEOS PGS-ERS RAW / IM 0 CEOS / ENVISAT VMP SLC CEOS 1x GEM6 PGS-ERS SLC / IMS CEOS / ENVISAT 1x WGS84 VMP PRI CEOS 3x GEM6 PGS-ERS PRI / IMP CEOS / ENVISAT 4x WGS84 VMP GEC 1 CEOS 3x GEM6 PGS-ERS IMG 1 ENVISAT 4x WGS84 VMP PGS-ERS IMM 2 ENVISAT 8x WGS84 Table 1. Lit of VMP and PGS-ERS product and main characteritic Note: (1) Geocoded Image were available in the pat but they were not tandard VMP product. They will be tandard product with the PGS-ERS ytem, equivalent to thoe available for ASAR Image Mode. (2) Medium reolution product were not available in the pat. They will be tandard product with the PGS-ERS ytem, equivalent to thoe available for ASAR Image Mode IS2. Initially, ERS SAR IMM product will have a maximum duration of 60 ec (1 lice). ERS SAR IMM tripline product, a long a the acquiition egment, will be available in autumn 2005.

8 The new ERS SAR Product iue 1 reviion 0 - page 1 of Naming convention for ERS-PGS product in ENVISAT format For product provided in ENVISAT format, the product naming convention i imilar to the one ued for ENVISAT product: i) Level-0 product: SAR_IM 0PxxxYYYYMMDD_HHMMSS_ddddddddPCCC_TTTTT_OOOOO_iiii.Ey Where: SAR_IM 0P: define the product type : proceing tage flag xxx: Originating facility YYYYMMDD (UTC): tart date of firt MDS record HHMMSS (UTC): tart time of firt MDS record dddddddd: product duration in econd P: phae identifier CCC: cycle number TTTTT: track (or relative orbit) number OOOOO: orbit number iiii: product file counter y: 1 (for ERS-1 product, ending with E1 ) 2 for ERS-2 product (ending with E2 ) ii) product: SAR_IMX_1PxxxYYYYMMDD_HHMMSS_ddddddddPCCC_TTTTT_OOOOO_iiii.Ey Where: SAR_IMX_0P: define the product type, namely: SAR_IMS_1P for Single Look Complex Image SAR_IMP_1P for Preciion Image SAR_IMG_1G for Geocoded Image SAR_IMM_1P for Medium Reolution Image And the other character are defined a for the Level-0 product. More detailed information regarding the product naming convention can be found in R-1.

9 The new ERS SAR Product iue 1 reviion 0 - page 1 of 22 3 VMP AND ERS-PGS CEOS FORMAT COMPARISON There are ome difference between CEOS product generated by the VMP and the PGS-ERS ytem, mainly due to the fact that ome field: aren t filled in the annotation are computed in a different way. It hall be treed that field not filled in the PGS-ERS CEOS format are not key parameter but redundant or auxiliary information not required for further pot-proceing. 3.1 General tructure The CEOS format i the ame for VMP and PGS-ERS product, baed on the following four file: Volume Directory File Leader File Data Set File Null Volume File The file tructure i the ame for the VMP and the PGS-ERS with the following difference: 2) The Leader File i maller in the PGS-ERS CEOS product (PRI and SLC) ince the Facility Data Record (PCS type) of byte i not available. RAW PRI SLC VMP byte byte byte PGS-ERS byte byte byte Table 2. Size of Leader file in CEOS format product 3) The Data Set File i maller in the PGS-ERS CEOS product (PRI and SLC). In fact, VMP CEOS product have a fixed number of ample per line (8000) and the record ize in the Data Set File i therefore contant for any product and equal to byte. Intead, the number of ample per line in the PGS-ERS CEOS product i variable from product to product (but contant for all the record of the ame product) and in general maller than 8000 ample. The table in the next ection report the difference in the annotation for RAW, SLC and PRI product proceed with the VMP and PGS-ERS ytem.

10 The new ERS SAR Product iue 1 reviion 0 - page 2 of Format difference for CEOS SAR RAW product The table below report the difference in the CEOS annotation for RAW product generated by the VMP and by the PGS-ERS ytem. The table i not intended to be a product format decription but only to highlight the main difference between the CEOS parameter provided by both ytem. Pleae note that when a parameter i Not provided by the PGS-ERS, it mean that the field i filled in with a dummy value (in general ) but the product format tructure remain the ame between both ytem (i.e. there i room allocated for that parameter, a in the VMP, even if it i not filled in or filled with dummy value) o that remaining parameter tay at the ame abolute location within the file). FIELD BYTES FORMAT DESCRIPTION VMP PGS-ERS Comment VOLUME DIRECTORY FILE Record Name: Volume Decriptor Record ID of phyical A16 volume containing thi volume decriptor LEADER FILE Record Name: Data Set Summary Record A16 Ellipoid deignator F16.7 Ellipoid emimajor axi F F F F16.7 Ellipoid emiminor axi Senor platform heading at nadir correponding to cene centre (clockwie poitive from North) DC bia for I component DC bia for Q component 126/ F16.7 Zero-doppler range time (two-way) of firt range pixel Zero-doppler range 126/ F16.7 time (two-way) of centre range pixel Zero-doppler range 126/ F16.7 time (two-way) of lat range pixel Record Name: Facility Related Data Record (General Type) Overall QA I4 ummary flag (Sum of the next 9 following flag) PRF code change I4 flag (0 = PRF contant in cene) Sampling window I4 tart time change flag (0 = SWST contant) Cal. ytem & I4 receiver gain change flag (0 = GEM6 Not WGS Not Not Not Not Not Not Not Not Not Not The ued ellipoid i different for VMP and PGS product in order to be complaint with the one ued for ENVISAT product. The ellipoid axe are lightly different. during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to Thi i alway equal to 0. No change expected in the receiver gain within one

11 The new ERS SAR Product iue 1 reviion 0 - page 3 of I I I I I I I F F16.7 Cal/Rx gain contant) Chirp replica quality flag (0 = Replica XCF in limit) Input data tatitic flag (0 = Raw data mean & d in limit) Number of PRF code change Number of ampling window time change Number of calibration ubytem gain change Number of miing line (i.e. raw data input line) Number of receiver gain change 3-dB width of Cro Correlation Function (CCF) between firt extracted chirp and nominal chirp Firt ide lobe level of chirp CCF Not Not Not Not Not Not Not Not Not F16.7 ISLR of chirp CCF Not F F F F F F F F F16.7 Etimated mean of I input data (once the nominal bia of 15.5 ha been applied) Etimated mean of Q input data (once the nominal bia of 15.5 ha been applied) Etimated tandard deviation of I input data Etimated tandard deviation of Q input data Calibration ytem gain of firt proceed line (telemetry value) Receiver gain of firt proceed line (telemetry value) Bia correction applied to I channel (to be added to the nominal bia) Bia correction applied to Q channel (to be added to the nominal bia) I/Q gain imbalance correction (applied Not Not Not Not Not Not Not Not Not cene. during the proceing to Thi i alway equal to 0. No change expected within one cene. during the proceing to Thi i alway equal to 0. No change expected within one cene. during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to Telemetry value Telemetry value during the proceing to during the proceing to during the proceing to

12 The new ERS SAR Product iue 1 reviion 0 - page 4 of F F F16.7 to Q channel) I/Q nonorthogonality correction (applied to Q channel) Range compreion normaliation factor Replica pule power Not Not Not F16.7 Incidence angle at firt range pixel (at mid-azimuth) Not Incidence angle at F16.7 centre range pixel Not (at mid-azimuth) Incidence angle at F16.7 lat range pixel (at Not mid-azimuth) Peak location of Cro Correlation I4 Function (CCF) between firt Not extracted chirp and nominal chirp 3-dB width of Cro Correlation F16.7 Function (CCF) between lat Not extracted chirp and nominal chirp Firt ide lobe level of chirp CCF F between lat Not extracted chirp and nominal chirp ISLR of chirp CCF F16.7 between lat extracted chirp and Not nominal chirp Peak location of Cro Correlation I4 Function (CCF) between lat Not extracted chirp and nominal chirp Sample per line I4 ued for the raw Not data analyi Range line kip I4 factor for raw data Not analyi PRF code of firt I4 range line Not (telemetry value) PRF code of lat I4 range line Not (telemetry value) Sampling window I4 tart time code of firt range line Not (telemetry value) Sampling window I4 tart time code of lat range line (telemetry value) F16.7 I/ gain imbalance - Lower bound Not F16.7 I/ gain imbalance - Upper bound Not F16.7 I/Q quadrature Not during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to during the proceing to Telemetry value

13 The new ERS SAR Product iue 1 reviion 0 - page 5 of F I4 departure - Lower bound I/Q quadrature departure - Upper bound Range preading lo compenation flag (0 = no compenation NULL VOLUME Record Name: Null Volume Decriptor Record ID of phyical A16 volume containing thi volume decriptor Not Not Not Range preading lo compenation doe not apply to level-0 product. Thi flag i alway equal to 0 for both the VMP and the PGS-ERS Table 3. Format difference between ERS VMP and PGS-ERS RAW CEOS product 3.3 Format difference for CEOS SAR SLC product The table below report the difference in the CEOS annotation for SLC product generated by the VMP and by the PGS-ERS ytem. The table i not intended to be a product format decription but only to highlight the main difference between the CEOS parameter provided by both ytem. Pleae note that when a parameter i Not provided by the PGS-ERS, it mean that the field i filled in with a dummy value (in general ) but the product format tructure remain the ame between both ytem (i.e. there i room allocated for that parameter, a in the VMP, even if it i not filled in or filled with dummy value) o that remaining parameter tay at the ame abolute location within the file). FIELD BYTES FORMAT DESCRIPTION VMP PGS Comment VOLUME DIRECTORY FILE Record Name: Volume Decriptor Record ID of phyical volume containing A16 thi volume decriptor LEADER FILE Record Name: File Decriptor Record I6 Number of facility data record Record Name: Data Set Summary Record Proceed cene F16.7 centre true heading A16 Ellipoid deignator F16.7 Ellipoid emimajor axi F F8.3 Ellipoid emiminor axi Senor platform geodetic latitude at nadir Not 2 1 Not GEM6 WGS Not The facility data record PCS type i empty for PGS proceed data (ee at the bottom of the table) The ued ellipoid i different for VMP and PGS product in order to be complaint with the one ued for ENVISAT product. The ellipoid axe are lightly different.

14 The new ERS SAR Product iue 1 reviion 0 - page 6 of 22 correponding to cene centre (poitive for North latitude) F8.3 Senor platform longitude at nadir correponding to cene centre (negative for Wet longitude) Cro track Doppler frequency F16.7 rate at early edge of image quadratic term Record Name: Map Projection Data Record Orientation at F16.7 output cene centre A32 Name of reference ellipoid F16.7 Semimajor axi of ref. Ellipoid F16.7 Semiminor axi of ref. Ellipoid Record Name: Facility Related Data Record (General Type) A F A6 Date of the lat calibration update <YYMMDD> Range compreion normalization factor Date on which K wa generated a YYMMDD Not GEM6 Not Not WGS Not Not Not A4 K verion number Not 76 to D F F F I I I I16 Acending node tate vector (X,Y,Z,X',Y',Z') 3-dB width of Cro Correlation Function (CCF) between lat extracted chirp and nominal chirp Firt ide lobe level of chirp (CCF) between lat extracted chirp and nominal chirp ISLR of chirp CCF between lat extracted chirp and nominal chirp Peak location of Cro Correlation Function (CCF) between lat extracted chirp and nominal chirp Update period of range-matched filter Number of azimuth block proceed Satellite binary time of firt range line Not Not Not Not Not Not Not Not The ued ellipoid i different for VMP and PGS product in order to be complaint with the one ued for ENVISAT product. The ellipoid axe are lightly different. Thi information i provided in the External Calibration auxiliary file ued by the PGS-ERS ytem in the proceing, imilar to the ENVISAT ASAR cae. Thi information i provided in the External Calibration auxiliary file ued by the PGS-ERS ytem in the proceing, imilar to the ENVISAT ASAR cae.

15 The new ERS SAR Product iue 1 reviion 0 - page 7 of 22 (telemetry value) 126 Number of range ample dicarded I4 during proceing interpolation Not Record Name: Facility Related Data Record (PCS Type) Filled record Empty Record NULL VOLUME Record Name: Null Volume Decriptor Record ID of phyical A16 volume containing thi volume decriptor Not Table 4. Format difference between ERS VMP and PGS-ERS SLC CEOS product 3.4 Format difference for CEOS SAR PRI product The table below report the difference in the CEOS annotation for PRI product generated by the VMP and by the PGS-ERS ytem. The table i not intended to be a product format decription but only to highlight the main difference between the CEOS parameter provided by both ytem. Pleae note that when a parameter i Not provided by the PGS-ERS, it mean that the field i filled in with a dummy value (in general ) but the product format tructure remain the ame between both ytem (i.e. there i room allocated for that parameter, a in the VMP, even if it i not filled in or filled with dummy value) o that remaining parameter tay at the ame abolute location within the file). FIELD BYTES FORMAT DESCRIPTION VMP PGS Comment LEADER FILE Record Name: File Decriptor Record I6 Number of facility data record Record Name: Data Set Summary Record Proceed cene centre true F16.7 heading a calculated relative to North A16 Ellipoid deignator F16.7 Ellipoid emimajor axi F F F8.3 Ellipoid emiminor axi Senor platform geodetic latitude at nadir correponding to cene centre (poitive for North latitude) Senor platform longitude at nadir correponding to cene centre 2 1 Not GEM6 WGS Not Not The facility data record PCS type i empty for PGS proceed data (ee at the bottom of the table) The ued ellipoid i different for VMP and PGS product in order to be complaint with the one ued for ENVISAT product. The ellipoid axe are lightly different.

16 The new ERS SAR Product iue 1 reviion 0 - page 8 of 22 (negative for Wet longitude) F16.7 Cro track Doppler frequency rate at early edge of image quadratic term Record Name: Map Projection Data Record Orientation at F16.7 output cene centre A32 Name of reference ellipoid F16.7 Semimajor axi of ref. ellipoid F16.7 Semiminor axi of ref. ellipoid Record Name: Facility Related Data Record (General Type) A I I F A6 Date of the lat calibration update <YYMMDD> Number of valid calibration pule Number of valid noie pule Range compreion normalization factor Date on which K wa generated a YYMMDD Not GEM6 Not WGS Not 0 Not 0 Not Not Not A4 K verion number Not A24 76 to D F F F I I I I16 Time of acending node tate vector (UTC) <dd-mmmyyyy$hh:mm:.ttt> Acending node tate vector (X,Y,Z,X',Y',Z') 3-dB width of Cro Correlation Function (CCF) between lat extracted chirp and nominal chirp Firt ide lobe level of chirp (CCF) between lat extracted chirp and nominal chirp ISLR of chirp CCF between lat extracted chirp and nominal chirp Peak location of Cro Correlation Function (CCF) between lat extracted chirp and nominal chirp Update period of range-matched filter Number of azimuth block proceed Satellite binary time of firt range line Not Not Not Not Not Not Not Not Not The ued ellipoid i different for VMP and PGS product in order to be complaint with the one ued for ENVISAT product. The ellipoid axe are lightly different. Thi information i provided in the External Calibration auxiliary file ued by the PGS-ERS ytem in the proceing, imilar to the ENVISAT ASAR cae Thi information i provided in the External Calibration auxiliary file ued by the PGS-ERS ytem in the proceing, imilar to the ENVISAT ASAR cae

17 The new ERS SAR Product iue 1 reviion 0 - page 9 of 22 (telemetry value) 126 Number of range ample dicarded I4 during proceing interpolation Not Record Name: Facility Related Data Record (PCS Type) Filled record Empty Record Table 5. Format difference between ERS VMP and PGS-ERS PRI CEOS product

18 The new ERS SAR Product iue 1 reviion 0 - page 10 of 22 4 CROSS-PROCESSOR INTERFEROMETRY Combining product generated by different proceing ytem i particularly critical when they are ued for interferometric pot-proceing and application. It i therefore important to ae the conitency between VMP and PGS-ERS SAR product and to enure they can be combined in the InSAR proceing without degrading the quality of the interferometric reult. A detailed analyi ha been performed uing an ERS-1/2 tandem dataet acquired over the ERS calibration ite (Flevoland) in The Netherland. The dataet i decribed in Table 6. Platform Orbit Track Acquiition Date ERS AUG :35:01 ERS AUG :35:06 Table 6: Input dataet definition The pair decribed above wa acquired during the ERS-1/2 tandem operation where the miion cenario had been optimized for interferometric application: ame orbital plane enuring imilar geometric acquiition condition cloe Doppler Centroid frequency one day delay between the two pae enuring imilar peckle characteritic Furthermore, the choen area i almot flat which hould avoid topographic effect.

19 The new ERS SAR Product iue 1 reviion 0 - page 11 of 22 Figure 1: Location of the ERS-1/2 cene. For the tet decribed below, SLC product have been generated by the VMP and the PGS-ERS in CEOS format. It ha been arbitrary choen to make the E2 cene the mater image and the E1 cene the lave. The reulting product have been combined in the InSAR proceing according to the following tet configuration, a decribed in Table 7: 1. Reference tet configuration: In thi cae, the tandard SLC product generated by the ESA VMP proceor are ued. Thi tet will provide the reference interferometric reult, to be compared with the cro-proceor tet reult. The reference reult are detailed in ection Cro-proceor tet configuration: In thi cae, the ame interferometric proceing a in the firt tet i performed> However, now the ERS-2 SLC product i the ame a in the firt tet (VMP) while the ERS-1 SLC product ha been here generated by the PGS-ERS ytem. The reult are detailed in ection 4.2 and they are to be compared with the reference tet one. It i hown that the ue of image coming from both VMP and PGS-ERS proceor doen t impact on the quality of the interferometric reult. Coherence i well preerved and coherence tatitic are globally and locally repected. Alo the phae characteritic are preerved.

20 The new ERS SAR Product iue 1 reviion 0 - page 12 of Phae preervation tet configuration: The purpoe of thi tet i to enure that the PGS-ERS/SLC product are phae preerving. The obtained interferometric phae hould ideally have a contant phae while the coherence hould be cloe to one over the whole image. Any variation from thee expected reult hould highlight any problem coming from proceing iue. It i indeed hown in ection 4.3 that the cro-proceor phae preervation tet give reult in agreement of the expected one. The coherence i cloe to one almot everywhere in the image and the phae difference characteritic are within the requirement given above. Tet Platform Proceor Doppler (Hz) ID 1-Reference 2-Cro-proceor 3-Cro-proceor Phae preervation ERS-2 VMP E2_VMP ERS-1 VMP E1_VMP ERS-2 VMP E2_VMP ERS-1 PGS-ERS E1_PGSERS ERS-1 VMP E1_VMP ERS-1 PGS-ERS E1_PGSERS Table 7: Tet definition

21 The new ERS SAR Product iue 1 reviion 0 - page 13 of Reference tet The purpoe of thi tet i to generate the reference reult to be compared againt the cro-proceor reult (tet 2) in ection 4.2. Figure 2 preent the main reult of thi tet, (a) the coherence, (b) the wrapped phae difference and (c) the unwrapped phae difference. (a) coherence image (b) wrapped interferogram Wrapped interferogram color table -180º 180º -180º 7916º Coherence color table 0 1 (c) unwrapped interferogram Figure 2: coherence and interferogram image from the reference pair E2_VMP/E1_VMP Pleae note that the image of Figure 2 a for all the image of thi report are left in the original imaging geometry (i.e. flipped eat-wet in thi cae).

22 The new ERS SAR Product iue 1 reviion 0 - page 14 of BASELINE CHARACTERISTICS Table 8 provide the interferometric baeline at different image poition. For thi data et, the baeline i rather mall (~52 m) enuring ame geometric characteritic. Azimuth poition baeline, Range poition,_ _, in (m) Near Mid Far Early Mid Late , , , , , , , , , , , , , , , , , Table 8: Baeline parameter of the reference pair. Firt the module and it decompoition in perpendicular and parallel component given in meter COHERENCE CHARACTERISTICS The coherence hitogram over the full cene (covering land and ea) i hown in Figure 3. Table 9 ummarize the coherence tatitic. Figure 3:Coherence hitogram. A value of 100 correpond to the maximum coherence of 1 Mean Std deviation Min Max Table 9: Statitic of the reference coherence image

23 The new ERS SAR Product iue 1 reviion 0 - page 15 of PHASE DIFFERENCE CHARACTERISTICS Figure 2.b how the wrapped interferogram where a pattern of ~20 orbital fringe i clearly viible leading to the unwrapped interferogram hown in Figure 2.c.

24 The new ERS SAR Product iue 1 reviion 0 - page 16 of InSAR cro-proceor tet The image diplayed in Figure 4 how the reult of the tet uing the ERS2/VMP and ERS-1/PGS-ERS image. The reult obtained have to be directly compared with thoe preented in ection 4.1. (a) coherence image (b) wrapped interferogram Wrapped and unwrapped interferogram color table -180º 180º -180º 7459º Coherence color table 0 1 (c) unwrapped interferogram Figure 4: Coherence and interferogram image from the pair E2_VMP/E1_PGSERS

25 The new ERS SAR Product iue 1 reviion 0 - page 17 of BASELINE CHARACTERISTICS The baeline calculation given below have to be compared with the reference one in ection 4.1. With repect to the reference given in Table 8, one hould note that a very mall baeline dicrepancy of le than 7cm i obtained. Thi i due to the fact that the orbit propagation oftware ued by both proceing ytem i lightly different. Azimuth poition baeline, Range poition _ _, (m) Near Mid Far Early Mid Late , , , , , , , , , , , , , , Table 10: Baeline parameter of the pair E2/VMP & E1/PGS-ERS. Firt the module and it decompoition in perpendicular and parallel component given in meter COHERENCE CHARACTERISTICS In term of coherence, the reult obtained are in agreement with the reference one. One hould note the high imilaritie between the coherence image (Figure 2.a and Figure 4.a) and between the related hitogram (Figure 3 and Figure 5). Table 11 provide a quantitative confirmation of the conitency between both coherence reult. Figure 5:Coherence hitogram. A value of 100 correpond to the maximum coherence of 1

26 The new ERS SAR Product iue 1 reviion 0 - page 18 of 22 Pair Mean Std deviation Min Max E2_VMP E1_PFERS E2_VMP E1_VMP (ref) Table 11: Coherence tatitic The conitency of coherence reult from both tet can be aeed through the ratio image between both coherence image. Clearly, a perfect match will reult in an image with all value equal to 1. Indeed, making the pixel that have coherence below 0.2 (mainly the ea/lake, naturally non-coherent), a mean ratio of 0.997±0.126 i obtained confirming a very high coherence imilarity PHASE DIFFERENCE CHARACTERISTICS The Figure 4.b and 4.c how the interferogram obtained from the pair ERS-2-VMP / ERS-1-PGS-ERS. It i poible to ee the imilaritie with the reference interferogram (Figure 2.b and 2.c). Alo the orbital fringe pattern i conitent.

27 The new ERS SAR Product iue 1 reviion 0 - page 19 of Cro-proceor phae preervation tet A pecial phae preerving tet ha been carried out between the SLC product generated from the ame ERS-1 RAW data by both the VMP and the PGS-ERS (thee are the ERS-1 product ued in Tet 1 and 2 previouly). The purpoe of thi tet i to demontrate the phae conitency between the VMP and the PGS-ERS proceing. Thi tet i uually performed between 2 product generated by the ame proceing ytem but when tarting the proceing at different range and azimuth poition. In thi cae, the proceing tart time in range and azimuth i not modified but two different proceor have been ued. Figure 6 how the reult of thi tet: (a) the coherence, (b) the wrapped phae difference and (c) the coherence obtained in the firt tet to ait the localization of the ub-image (a) and (b) within the full product.

28 The new ERS SAR Product iue 1 reviion 0 - page 20 of 22 (a) coherence image ERS-1 VMP / ERS-1 PGSERS (b) wrapped interferogram ERS-1 VMP / ERS-1 PGSERS -180º 180º Wrapped interferogram colour table (c) coherence image ERS-2 VMP / ERS-1 VMP Figure 6: Interferometric reult from the pair E1_VMP/E1_PGSERS BASELINE CHARACTERISTICS Since both proceor don t ue the ame orbit propagator, the reulting baeline i not exactly equal to 0. Table 11 give the baeline at different image poition.

29 The new ERS SAR Product iue 1 reviion 0 - page 21 of 22 baeline, Range poition Mod, _ _, (m) Near Mid Far Azimuth poition Early Mid Late , , , , , , , , , , , , , , , , , , Table 11: Baeline parameter of the pair E1_VMP / E1_PFERS. Firt the module and then the decompoition in perpendicular and parallel component given in meter COHERENCE CHARACTERISTICS A uniform coherence very cloe to 1 i obtained almot everywhere a hown in Figure 7 that illutrate the hitogram of coherence. Figure 7: Coherence hitogram PHASE DIFFERENCE CHARACTERISTICS The hitogram of the phae difference in Figure 8, how a table phae having a mean value cloe to 0.1 with an average tandard deviation of 5.6, which are within the requirement of the tandard phae preerving tet (uing twice the ame proceor).

30 The new ERS SAR Product iue 1 reviion 0 - page 22 of 21 Figure 8: Hitogram of interferometric phae for the pair E1_VMP/E1_PGSERS