GNSS-Reflectometry for Observation and Monitoring of Earth surface Global Navigation meets Geoinformation ESA ESOC Darmstadt, 28-04-2017 Dr. Ing. Domenico Schiavulli INR engineer support at EUMETSAT
Outline Introduction GNSS-R concept A powerful tool for Remote Sensing Summary and Conclusions
Introduction Outline
Introduction GNSS are worldwide satellite constellations continuously transmitting L band signals, i.e. all weather night-and-day signals. GPS 24 satellites Galileo 30 satellites Beidou 35 satellites Glonass 24 satellites
Introduction GNSS are designed to provide Positioning, Velocity and Timing (PVT) to an user with a receiver.
Introduction GNSS are designed to provide Positioning, Velocity and Timing (PVT) to an user with a receiver. Navigation services are provided by analyzing the direct signal, while signals reflected off surfaces or obstacles, i.e. multipath, are filtered out Direct signal Multipath
GNSS-R concept Outline
GNSS-R concept GNSS-Reflectometry exploits GNSS signals reflected off Earth s surface to infer geophysical information of the scattering area
GNSS-R concept GNSS-Reflectometry exploits GNSS signals reflected off Earth s surface to infer geophysical information of the scattering area BISTATIC/MULTISTATIC RADAR SYSTEM
GNSS-R concept GNSS-R geometry is defined as: SP - Specular Point (SP): the shortest path TX-scattering scene-rx; - Iso-Delay ellipses: points whose scattered signals experience the same delay; - Iso-Doppler hyperbolae: points whose scattered signals experience the same frequency shift.
GNSS-R concept The GNSS-R measurement are mapped in the Delay-Doppler Map (DDM) or 1-D Delay waveform
Doppler GNSS-R concept The GNSS-R measurement are mapped in the Delay-Doppler Map (DDM) or 1-D Delay waveform Delay SP
Doppler GNSS-R concept The GNSS-R measurement are mapped in the Delay-Doppler Map (DDM) or 1-D Delay waveform Delay SP SP Delay
GNSS-R concept SAR, ALTIMETER, SCATTEROMETER Service and Product
GNSS-R concept GNSS-R main advantages with respect dedicated sensors: - Excellent spatial and temporal coverage; - GNSS long term mission; - Cost effectiveness
GNSS-R concept The importance of this promising and innovative technique is confirmed by dedicated space missions: US NASA CYGNSS constellation UK TechDemoSat-1 ESA GEROS-ISS
Outline A powerful tool for Imaging Remote Sensing
Doppler A powerful tool for Imaging Remote Sensing GNSS-R measurements: Delay Delay
Doppler A powerful tool for Imaging Remote Sensing GNSS-R measurements: Delay Delay SPATIAL INFORMATION ON THE OBSERVED SCENE IS LOST
Doppler A powerful tool for Imaging Remote Sensing GNSS-R measurements: Delay SPATIAL INFORMATION ON THE OBSERVED SCENE IS LOST Delay TEHCNIQUES ARE NEEDED TO TRANSFORM: (Δτ,Δf) (x,y)
Outline A powerful tool for Imaging Remote Sensing Oil spill in simulated environment
A powerful tool for Imaging Remote Sensing Cosmo SkyMed SAR image Simulated marine scenario including oill spill
A powerful tool for Imaging Remote Sensing Simulated scenario Noisy DDM
A powerful tool for Imaging Remote Sensing Processing time = 10s Inverse Problem TSVD applied Simulated scenario Noisy DDM Reconstructed scenario
Outline A powerful tool for Imaging Remote Sensing Sea/Ice transition detection using TechDemoSat-1 data
A powerful tool for Imaging Remote Sensing Track ID: TD000148 Start acquisition time: 2014-10-31 09:20:53 Signal type: GPS L1 End acquisition time: 2014-10-31 10:00:50 PRN: 31
A powerful tool for Imaging Remote Sensing SP Acquisition time: 2014-10-31 09:40:53 SP position: 44.7 S, 10.8 W Land type: waterbodies
A powerful tool for Imaging Remote Sensing Open ocean DDM Ice DDM
A powerful tool for Imaging Remote Sensing Measured DDM Sea ice concentration -Green line is the satellite ground track - Red square is the observed area
A powerful tool for Imaging Remote Sensing SSM-I sea ice concentration Reconstructed radar image
A powerful tool for Imaging Remote Sensing
A powerful tool for Imaging Remote Sensing Sentinel-1 HH SAR image Reconstructed radar image
A powerful tool for Imaging Remote Sensing
Outline Summary and Conclusions
Summary and Conclusions The FORCE of proposed approach: - Added value products to improve/complement dedicated sensors provided they are -A new typo of service and product can be offered to the community - Applications such as target detection, sea/ice transition, etc.. can strongly benefit from these innovative products
Summary and Conclusions The FORCE of proposed approach: - Added value products to improve/complement dedicated sensors provided they are -A new typo of service and product can be offered to the community - Applications such as target detection, sea/ice transition, etc.. can strongly benefit from these innovative products The DARK SIDE of the FORCE: The resolution is still coarse. The receiver time coverage is still coarse Both problems can be overcome by using the future constellations of receiver, e.g. CYGNSS or CubeSAT.
domenico.schiavulli@gmail.com domenico.schiavulli@eumetsat.int THANK YOU