THE SENTINEL-1 MISSION AND ITS APPLICATION CAPABILITIES

We care for a safer world

For further information please visit:

ESA GMES website EC GMES websitewww.esa.int/gmes www.ec.europa.eu/gmes

Emergency Response


Ramón TorresGMES Sentinel-1 Project Manager

ESA - ESTEC

24 July 2012

The Sentinel-1 Mission and its Application Capabilities

3

Presentation Outline

• Mission Objectives and Requirements

• Key Mission and System Facts

• Acquisition modes and performance

• Observation Strategy

• Observation Scenario

• Applications

• Conclusions


Mission Objectives and Requirements

• Provide routinely and systematically SAR data to GMES Services

and National services

Marine Monitoring (e.g. oil spill, sea ice)

Land Monitoring (e.g. land cover, surface deformation)

Emergency Response

Climate Change (e.g. Polar caps incl. ice shelves and glaciers)

Security (e.g. marine surveillance and ship detection)

• Provide C-band SAR data continuity of ERS/ENVISAT type of

missions at medium resolution (10 m and lower)

• Greatly improved coverage and revisit (i.e. as compared to

ENVISAT)

• Conflict-free operations (wide swath and dual-pol modes)

• High system availability (SAR duty cycle and data latency)

• Data quality similar or better than ERS/ENVISAT (e.g. equalized

performance across the swath)


Key Mission Facts

• Constellation of two satellites (A & B units)

• Near-Polar sun-synchronous (dawn-dusk) orbit at 693 km mean altitude

• Both S-1 satellites are in the same orbit (180 deg. phased in orbit)

• 12 days repeat cycle (1 satellite), 6 days for the constellation

• 7 years design life time with consumables for 12 years

• Launch of Sentinel-1A October 2013. Sentinel-1B will be ready for launch in the first half of 2015 subject to EC funding

Prime contractor: Thales Alenia Space, Italy

Instrument responsible: EADS Astrium, Germany


Key System Facts

• C-Band SAR instrument operates at centre frequency of 5.405 GHz

• On-board data storage capacity (mass memory) of 1400 Gbit

• Two X-band RF channels for data downlink with 2 X 260 Mbps

• On-board data compression using Flexible Dynamic Block Adaptive Quantization

• Optical Communication Payload for data transfer via laser link with the GEO European Data Relay Satellite (ERDS) system


400 Km

400 Km

250 Km

200

Km

100

Km

80 Km

23o

36o

S1

S6Stripmap Mode (SM)

Interferometric Wide

Swath Mode (IW)

Extra Wide

Swath Mode (EW)

Wave Mode (WV)

19o

46o

30o

45o

19o

46o Sentinel-1 SAR can be operated in 4 exclusive measurement modes with different resolution and coverage

Polarisation schemes for IW, EW & SM:• single polarisation: HH or VV• dual polarisation: HH+HV or VV+VH

Polarisation scheme for WM: HH or VV

SAR duty cycle per orbit:• up to 25 min in any of the imaging

modes• up to 74 min in WM

SAR Acquisition Modes

IW: main mode of operation satisfying most of user and servicesWV: continuously operated over open ocean


SAR Mode Performance

Mode Access Angle

Single Look Resolution

Swath Width Polarisation

Interferometric Wide Swath

> 25 deg.

Range 5 m

Azimuth 20 m

> 250 km HH+HV or VV+VH

Wave mode 23 deg.and36.5 deg.

Range 5 m

Azimuth 5 m

> 20 x 20 km

Vignettes at

100 km intervals

HH or VV

Strip Map 20-45 deg.

Range 5 m Azimuth 5 m


Extra Wide Swath > 20 deg. Range 20 m

Azimuth 40 m


Image Quality Parameters for all Modes (worst case)

Radiometric accuracy (3 σ) 1 dB

Noise Equivalent Sigma Zero -22 dB

Point Target Ambiguity Ratio -25 dB

Distributed Target Ambiguity Ratio -22 dB

Main modes for operations


Based on optimum use of SAR duty cycle (25 min/orbit) satisfies the GMES user/service requirements (i.e. resolution, swath width,

polarisation) increases revisit time and coverage enables build-up of long-term data time series provides high level of automation for mission planning allows pre-defined operations minimizes potential conflicts during operations, considering

various constraints (e.g. mode transition times, X-band switches)

Sentinel-1 Observation Strategy

• Over land and maritime shipping routes: IW is pre-defined mode

• Over Polar areas (i.e. sea ice): IW mode is pre-defined mode (EW could be used if decrease in radiometric resolution is acceptable)

• Emergency observation requests may alter the pre-defined observation scenario: use of e.g. SM mode

• Over open ocean: WV mode is continuously operated


Sentinel-1 Observation Scenario

Sea-ice monitoring services in the North Hemisphere



Sentinel-1 Real-Time (10min) requirements from EMSA (CleanSeaNet Oil Spill Monitoring Service)


S-1A Satellite S-1A + S-1B Satellites

Complete global

coverageAfter 12 days After 6 days

Ice MTZ Europe Canada Rest of

Land

Ice MTZ Europe Canada Rest of

Land

Number of

acquisitions (range

from - to)

1-9 1-6 1-5 1-4 1-6 2-18 2-12 2-10 2-8 2-12

Average Revisit

Time [day] 8,0 3,7 5,5 8,2 9,9 5,0 1,9 2,7 4,1 4,9

Average Revisit Time with S-1A + S-1B SatellitesAverage Revisit Time S-1A Satellite

Sentinel-1A Observation Scenario


Sentinel-1 Applications: Ship Detection

Sm

alle

r sh

ips

100m

30m


Sentinel-1 Applications: Dyke Monitoring (INSAR)

– Estimated sea-level rise impacts in the Netherlands and Germany.

– 0.65 m (dark blue) and 1.3 m (light blue)

Courtesy Hansje Brinker BV


Sentinel-1 Applications: Land cover classification

Based on multi-temporal scene

acquisitions


Sentinel-1 Applications: Ice Classification

– ENVISAR ASAR image

separating thinner, more

navigable first year ice

from the hazardous,

stronger and much

thicker multi-year ice.

Courtesy of the Canadian Ice

Service.


Applications Performance Prediction

S1 Level-2 Product Resolution Performance Units

Subsidence Rate 5 x 20 m2 1.3/1.3 mm/year

Land Cover Classification (2 dB contrast )

30 x 30 m2 90/75 % correct classification

Forest Non-Forest Classification

30 x 30 m2 98.6/75 % correct classification

Soil Moisture 100 x 100 m2 0.8/1.2 volume %

Flood Mapping 30 x 30 m2 93/79 % correct classification

Snow Cover Classification

30 x 30 m2 80/75 % correct classification

Ship Detection 5 x 20 m2 20/40 ship length (m)

Sea Surface Wind Speed 100 x 100 m2 0.4/0.8 m/s

Sea Surface Currents 5 Hz 30/30 cm/s


Conclusions

• Sentinel-1 is the GMES European Radar Observatory that will ensure the continuation and improvement of SAR operational services of medium- to high-resolution applications

• Sentinel-1 will become one of the main data sources for the six GMES service themes identified by the European Commission for which it will support the provision of operational services based on Earth observation data: Emergency Response, Marine Monitoring, Land Monitoring, Atmospheric Monitoring, Security, and Climate

• The System is optimised to a main mode of operation that features both a wide swath (250 km), high geometric resolution (5 × 20 m) and high radiometric accuracy (1dB 3σ), allowing imaging of global landmasses, coastal zones, sea ice, polar areas, and shipping routes at high resolution, in a repeat cycle of 12 days


Conclusions

• Sentinel-1 is designed to respond to emergency requests to support disaster management in crisis situations but otherwise works in a pre-programmed conflict-free operation mode that will ensure the reliability required by operational services and will create a consistent long-term data archive for applications based on long time series

• The Spacecraft are being built by an industrial consortium led by Thales Alenia Space (Italy) as the Prime Contractor, while Astrium GmbH (Germany) is responsible for the C-band Synthetic Aperture Radar (CSAR) payload, which incorporates the central radar electronics subsystem developed by Astrium Ltd. (UK)

• The Sentinel-1A Spacecraft is scheduled to be launched in October 2013 with Soyuz from Kourou

THE SENTINEL-1 MISSION AND ITS APPLICATION CAPABILITIES

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