1. END-TO-END PERFORMANCE ANALYSIS OF THE PARIS IN-ORBIT DEMONSTRATOR OCEAN ALTIMETER Salvatore D’Addio, Manuel Martin-Neira , Chris Buck Acknowledgment: Nicolas Floury, Roberto Pietro Cerdeira TEC-ETP, Electrical Engineering Department European Space Agency

5. PARIS IoD Mission Summary Table Main passenger Piggy back Launcher Configuration PROTEUS-like PROBA-like Platform < 5-7.5 cm < 17-20 cm Total Altimetry Accuracy (1  ) All 3 bands of GPS, GLONASS, GALILEO, BEIDOU GPS L1+L5 Galileo E1+E5 Frequencies 16 4 Number of Beams 2.4 m / 30 dB 0.9 m / 19 dB Antenna Diameter / Gain < 100 km 100 km Spatial Resolution 2 days 3 days Revisit Time 1500 km 900 km Swath 1500 km 800 km Orbital Height Polar Sun Synchronous Polar Sun Synchronous Orbit Operational Mission In-orbit Demonstrator Tsunami detection Particular Application Ionospheric total electron content Wind speed and wind direction over ocean Significant Wave Height Mean Square Slope of ocean surface Sea Ice Extent River and lake water level Scientific by-products Polar Ice Thickness Secondary Scientific Product Mesoscale Ocean Altimetry Main Scientific Product PARIS Altimeter Instrument

7. Max Incidence Angle (1/2) The incidence angle plays an important role in the definition of critical parameters of the PARIS mission, such as: (a) Precision (b) Sampling and Coverage P G O s Ionosphere i i

8. Max Incidence Angle (2/2) a) Altimetric performance degrades with incidence angle b) Ionospheric delay and antenna loss increase with incidence angle The incidence angle should be restricted (<35  ). Coverage and sampling obtained by raising orbital height. (a ) (b) i Antenna gain P G O s Ionosphere i i

11. Cross-Correlation Integration Time (Tc) Interferometric Processing Schematic For a given target along track spatial resolution, e.g. 100Km , the coherent integration time and the incoherent averaging are inversely proportional : Tc Ninc

12. Cross-Correlation Integration Time (Tc) 1 chip delay

13. Cross-Correlation Integration Time (Tc) Low Tc High Tc

14. Cross-Correlation Integration Time (Tc) SNR SP T C

22. Ionospheric Correction: Example 2/2 Vertical Delay (m) Mesoscale Delay (m) Residual Delay (m) 200 km averaging of mesoscale delay applied  0.15 m +0.15 m +6 m  10 m +12 m 0 m Derived from RA-2 real data

23. PARIS IoD Preliminary Error Budget 5 cm Troposphere (Wet and Dry) 2 cm EM Bias 1 cm Skewness Bias 5 cm Orbit / Geometry 2 cm Instrument error residuals Ionosphere Residual Total RMS Height Accuracy Instrument Noise and Speckle Ionosphere Averaging Noise 18 cm at Edge of Swath 5 cm 9.5 cm (2 frequencies, N=3) 12.5 cm IOD Height Total Accuracy on 100Km, G=20dBi, H=800Km Parameter