Simulations and exploitation of GNSS-R signals from a 60-meter lighthouse for applications in surface hydrology processes Nicolas ROUSSEL Laurent LESTARQUIT PhD advisers: Guillaume RAMILLIEN, Frédéric FRAPPART 04/05 novembre 2013

2 Plan Introduction Simulations Field measurements  Introduction  Simulations  Field measurements  GNSS-based tide gauge system with SILICOM datalogger  Analysis of signal-to-noise ratio (SNR) series 4/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

Plan Introduction Simulations Field measurements  Introduction  Simulations  Field measurements  GNSS-based tide gauge system with SILICOM datalogger  Analysis of signal-to-noise ratio (SNR) series 34/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

 Ground configuration  Embedded configuration Direct/reflected signals correlation  Position of the specular reflection point  Altimetry  Properties of the reflection surface (roughness) Source : Institut de Ciències de l’Espai ( Introduction Introduction Simulations Field measurements 44/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

- 60 m - Introduction Introduction Simulations Field measurements  The Cordouan Lighthouse (45°35’11’’N ; 1°10’24’’O) 54/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

Plan Introduction Simulations Field measurements  Introduction  Simulations  Field measurements  GNSS-based tide gauge system with SILICOM datalogger  Analysis of signal-to-noise ratio (SNR) series 64/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

 Modeling the trajectories of GNSS electromagnetic waves that are reflected on the surface of the Earth, based on real ephemeris  Determine the potential of GNSS-R for mapping the characteristics of the reflecting surface  Explore different configurations of performing measurements and instrument installations:  variations in the reflectometer height, mask effects due to the terrain, satellites geometry,... Simulator development Simulations Introduction Simulations Field measurements 74/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

84/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT  Determination of the position of the specular reflection points: 3 algorithms -Approximation of the Earth into a local sphere -Approximation of the Earth into a local ellipsoid -DEM (Digital Elevation Model) integration Correctness Computation speed Gnu R For further information : Simulations of direct and reflected waves trajectories for in situ GNSS-R experiments, submitted in Geosciences Model Development N. Roussel, F. Frappart, G. Ramillien, C. Desjardins, P. Gegout, F. Pérosanz, R. Biancale Simulations Introduction Simulations Field measurements

94/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT Simulations Introduction Simulations Field measurements

Simulator outputs  Simulations on the Cordouan lighthouse (45°35’11’’N ; 1°10’24’’O) Simulations Introduction Simulations Field measurements 104/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

Simulations over a week Simulations Introduction Simulations Field measurements 114/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

Simulations over a week Simulations Introduction Simulations Field measurements 124/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

 Introduction  Simulations  Field measurements  GNSS-based tide gauge system with SILICOM datalogger  Analysis of signal-to-noise ratio (SNR) series 134/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT Plan Introduction Simulations Field measurements

14 Plan Introduction Simulations Field measurements  Introduction  Simulations  Field measurements  GNSS-based tide gauge system with SILICOM datalogger  Analysis of signal-to-noise ratio (SNR) series 4/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

SILICOM Data-Logger Data Logger  records and time tags a wide choice of supported RF GNSS signals  makes possible the characterization of the reflected signal and the development of algorithms for processing the GNSS-R signals. SILICOM Data-logger Introduction Simulations Field measurements 154/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

31 st may 2013 campaign Data Logger  to collect GNSS-R signals, receiving the direct signal via a RHCP zenith-looking antenna, and the reflected signal via a LHCP nadir-looking antenna Approx. 25 min of acquisitions, 25 MHz, 8 bits SILICOM Data-logger Introduction Simulations Field measurements 164/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

Acquisition  1 ms  Doppler : [-5000:1:5000] Hz  Detection of 6 satellites : -PRN12 -PRN15 -PRN17 -PRN24 -PRN25 -PRN26 In agreement with the simulations SILICOM Data-logger Introduction Simulations Field measurements 174/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

Acquisition Reflected signal Direct signal PRN15 exemple : detection of the initial doppler SILICOM Data-logger Introduction Simulations Field measurements 184/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

Acquisition Reflected signal Direct signal PRN15 exemple : detection of the initial delay SILICOM Data-logger Introduction Simulations Field measurements 194/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

Correlation function Reflected signal Direct signal SILICOM Data-logger Introduction Simulations Field measurements 1 ms 100 ms 204/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

Correlation function SILICOM Data-logger Introduction Simulations Field measurements Reflected signal Direct signal 1 ms 100 ms 214/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

Delay-Doppler Maps SILICOM Data-logger Introduction Simulations Field measurements 244/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT Ce sont des GIFS animés ! - 

Tracking SILICOM Data-logger Introduction Simulations Field measurements 234/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT Differences between direct and reflected paths – C/A PRN12 Time (s) Distance (m)

Tracking Direct signal Satellite NumReceiver height h (m) PRN1257,47 PRN1560,47 PRN1757,75 PRN2461,98 PRN2561,66 PRN2659,46 Mean59,80 ± 1,92 SILICOM Data-logger Introduction Simulations Field measurements 234/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

25 Plan Introduction Simulations Field measurements  Introduction  Simulations  Field measurements  GNSS-based tide gauge system with SILICOM datalogger  Analysis of signal-to-noise ratio (SNR) series 4/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

26 Plan Introduction Simulations Field measurements  Introduction  Simulations  Field measurements  GNSS-based tide gauge system with SILICOM datalogger  Analysis of signal-to-noise ratio (SNR) series 4/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

phase difference between the direct signal and the reflected signal (multipath) Direct signal amplitude Multipath amplitude x = sin θ : SNR data Introduction Simulations Field measurements Larson et al., GPS Sol., /5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

SNR data Introduction Simulations Field measurements L2 SNR data 2 nd order polynom 284/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT

SNR data Introduction Simulations Field measurements 294/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT L2 SNR data 0 – 40° elevation filtration

SNR data Introduction Simulations Field measurements L2 SNR data 304/5 November 2013Space Reflecto – Nicolas ROUSSEL / Laurent LESTARQUIT  The whole 3 months time series is currently being analyzed in order to make the tide appear

Thanks for your attention !