M. Manunta, Berardino P., Bonano M., De Luca C., De Novellis V., Elefante S., Fusco A., Lanari R., Manzo M., Ojha C., Pepe A., Sansosti E., Zinno I., Casu F.

CNR IREA, Via Diocleziano 328, 80124 Napoli (Italy)

Achieved accuracies:

• ≈ 1 - 2 mm/year on the mean deformation velocity

• ≈ 5 - 10 mm on the single displacement

exploiting interferograms characterized by a “small baseline” in order to limit the noise (decorrelation) phenomena, thus maximizing the number of investigated pixels;

PhU operation is usually performed by applying MCF or EMCF techniques.

using no a priori or model information on the investigated deformation signal;

The SBAS approach allows to produce “long term” deformation times-series by:

SBAS approach: key points

Interferometric Pair Selection

Geometrical Registration

Spectral Diversity

Compensation

Interferogram Generation

Phase Unwrapping

Time-series Generation

Deformation Time-series

S1 SBAS-DInSAR Block Diagram

Data Ingestion

Acquisition Time

S-1A SBAS approach: pair selection

The number of interferograms is about 3*(Number of acquisitions)

Orbital tube of Sentinel-1 should be very short, therefore no perpendicular baseline constraint needs to be applied. To get redundancy of interferograms, each acquisition is coupled with the 3 following scenes in time.

Orbit Registration: Rigid offset. It is retrieved in one point exploiting orbit and target location (DEM) information.

Coherence Maximization: Rigid offset. It is retrieved in one patch by maximizing the number of coherent points.

Geometric Registration: it is performed point by point, using orbit and location (DEM) information.

Spectral Diversity Compensation: the residual phase, estimated through Spectral Diversity method, is compensated directly from interferograms, without performing again the interpolation of slave images.

Co-Registration Scheme

Interferometric Pair Selection

Geometrical Registration

Spectral Diversity

Compensation

Interferogram Generation

Phase Unwrapping

Time-series Generation

Deformation Time-series

S1 SBAS-DInSAR Block Diagram

Data Ingestion

Spectral Diversity Scheme

Inter-Swath overlapping: the 2 bursts have a shift of about 500 samples, corresponding to 800 Hz Hz

Samples

500 Samples

800 Hz

Inter-Swath Overlap

∆dop≅800 Hz

∆dop≅2400 Hz

Shift max: ± 0.3 samples

Shift max: ± 0.1 samples

Spectral Diversity Scheme

The spectral diversity method is applied: • first in the inter-swath areas, to

estimate larger shifts; • then in the inter-burst areas, to

accurately estimate the residual shift.

This double step allows us to limit phase ambiguity problems in the shift estimation.

Spectral Diversity Scheme

Acquisition Date

Shift of Ann. St. Vec. [samples]

Shift of Rest. St. Vec. [samples](S1A_OPER_AUX

_RESORB) Orbit Coherence Orbit Coherence

20-10-2014 0.0 0.0 0.0 0.0 01-11-2014 6.806 6.981 6.963 6.996 13-11-2014 1.546 1.296 1.276 1.293 25-11-2014 7.110 7.335 NA NA Mean Error 0.21 0.02

Orbit Information: Annotated vs. Restituted Restituted: 10-sec State Vectors Annotated: 1-sec State Vectors

Burst Misalignments

B1 B2

Start Time of B2 usually does not correspond to a B1 sample:

TstB

1

TstB

2

This misalignment has to be properly compensated in the registration phase.

St. Dev. Residual Shifts [samples] Interferogram With Registration Without Registration

01122014_18012015 0.0021 0.0068 01122014_25122014 0.0013 0.0100 01122014_30012015 0.0013 0.0080 14102014_01122014 0.0018 0.0141 14102014_25122014 0.0011 0.0159 14102014_26102014 0.0011 0.0182 18012015_30012015 0.0015 0.0090 25122014_18012015 0.0012 0.0093 25122014_30012015 0.0009 0.0093 26102014_01122014 0.0020 0.0153 26102014_18012015 0.0019 0.0127 26102014_25122014 0.0017 0.0091

Mean Standard Deviation 0.0015 0.0115

Burst Misalignments

Fogo Volcano (Cape Verde) 03112014_27112014 b ⊥≅ 16 m

S-1A First Results: Fogo Volcano (Cape Verde)

S-1A First Results: Hawaii (USA)

S-1A First Results: Hawaii (USA)

Azim

uth

07-Dec-2014 12-Jan-2015

Sentinel Asc

S-1A First Results: Mt. Etna

Azim

uth

22-Dec-2014 02-Jan-2015

TSX Asc 131

S-1A First Results: Mt. Etna

Baseline Acq. Time Perp. [m] Parallel [m] Along track [m]

04042013 -27 -30 14

28042013 -120 -98 -13

22052013 -65 -53 -22

15062013 70 30 -12

09072013 129 81 -13

02082013 0 0 0

26082013 -117 -99 8

19092013 50 -36 10

13102013 -35 -103 29

06112013 124 21 20

30112013 -23 -82 9

TOPS SBAS results: Mexico City RS2 campaign

Azimuth

Rang

e

Several RS2 TOPS scenes are affected by significant orbit errors

RS2 TOPS interferograms show good coherence (24 days revisit time)

TOPS SBAS results: Mexico City RS2 campaign

RS2 TOPS interferograms: orbital parameter correction

Azimuth

Rang

e

Pepe et al., SBAS-Based Satellite Orbit Correction for the Generation of DInSAR Time-Series: Application to RADARSAT-1 Data, TGRS, 2011

Mea

n ve

loci

ty [c

m/y

r]

>20

<-20

TOPS SBAS results: Mexico City RS2 campaign

S-1A First Results: Istanbul (Turkey)

S-1A First Results: Sakurajima Volcano (Japan)

S-1A First Results: Hawaii (USA)

Mea

n ve

loci

ty [c

m/y

r]

>25

<-25

Upcoming steps: S1 SBAS chain within GEP

The S1 SBAS processing chain is currently under development to be integrated within ESA Geohazards Exploitation Platform (GEP).

https://geohazards-tep.eo.esa.int

S1 Processing on demand (G-POD)

Archives

G-POD User

Web Interface Computing Power

P-SBAS service (or other tools)

EPOS User

G-POD Web Portal of P-SBAS service

Paper 179 - Session title: PSI and DInSAR (3) 11:30 A Cloud Computing Approach for Big DInSAR Data Processing through the P-SBAS Algorithm

Paper 161 - Session title: PSI and DInSAR (3) 11:50 P-SBAS Service within ESA G-POD Platform for Unsupervised on Demand DInSAR Processing

http://gpod.eo.esa.int - eo-gpod@esa.int

Welcome Sentinel-1