3. 1. PAU-SA Instrument / 13 PAU-SA in the robotic arm 8 m PAU-RAD PAU-GNSS-R PAU-IR

4. / 13 2. Potential improvements for future SMOS’s Parameter MIRAS/SMOS PAU-SA Comments Frequency operation L-band (1400 - 1427 MHz) L-band (1575.42 MHz) L1 of GPS signal Same frequency both Radiometry and GPS Reflectrometry Bandwidth 19 MHz 2.2 MHz Spatial correlation effects negligible Larger  T Arm size 4 m 1.3 m Altitude Global observation, LEO, orbital altitude ground-based - Antenna type Patch antenna with V & H polarizations (not simultaneous) Patch antenna with V & H polarizations (simultaneous) Full-pol (non-sequential) Number of antennas per arm 23 8 +1 (dummy) Improve antenna pattern similarity Number total antennas 69 31 - Antenna spacing 0.875  at 1400 MHz, (21 cm) 0.816  at 1575.42 MHz, (15.5 cm) Increase the alias-free field of view Receiver type single polarization (1 per element) dual polarization (2 per element) Full-pol (non-sequential) Topology of the LO down-converter Distributed LO (groups of 6 elements) Centralized reference clock + internal LO generated in each receiver Reduce LO leakage and correlated offset Quantization 1 bit (Inside the LICEF ) 8 bits IF sub-sampling using a external ADC Digital I/Q demodulation Digital Power measurement Digital LPF I/Q conversion Analog Digital Elimination quadrature error Frequency response shaped by Analog RF filter Digital low- pass filter Mass reduction, quasi perfect matching, no temperature and aging drifts Power measurement system (PMS) Analog (Schottky diode) Digital (FPGA) Mass reduction, Thermal drifts minimized Calibration by Noise Injection Injection of Distributed noise Injection of Centralized noise or PRN signal Simpler calibration. Calibration of non-separable errors Recs’ freq. response estimation Image capabilities Dual-pol or full-pol (sequential) Full-pol (non-sequential) Necessary to GNSS-R applications

6. 3.2. Use of PRN Signals for: Receiver’s frequency response / 13 A S PRN +S R2 S PRN +S R1 Correlation of receivers’ output with local replica of PRN signal injected allows individual frequency responses to be measured (amplitude and phase) Using: PRN sequences

9. 5.1. Preliminary results (i): Impulse response / 13 FFT Point Source : PRN signal (-70 dBm) Moving the Instrument (no temperature control) El +/- 10º, +/- 20º Az +/- 10º, +/- 20º Pol H Az= 0º El= 0º Pol H Az= +10º El= 0º Pol H Az= +20º El= 0º Pol V Az= 0º El= +10º Pol V Az= 0º El= +20º PRN Signal Rectangular window for visibility samples Antenna 1 PRN Source 1 Instrumen t

10. 5.2. Preliminary results (ii): Angular resolution / 13 FFT Point Source : PRN signals (-70 dBm) 7 antennas per arm + rectangular window Sources – PAU-SA distance at 10 m Angular resolution  ( ξ , η ) ~ 5.7º 2 PRN Signals Rectangular window PRN Source 1 Antenna 1 PRN Source 2 Antenna 2 Instrumen t Antennas separation at: (Near field) No near-to-far field transformation applied 1 m 2 m 3 m 4 m

11. 5.3. Preliminary results (iii): GPS satellites / 13 FFT GPS Signal Rectangular window UPC location GPS orbit UTC 12:44:03 K UTC 12:22:03 K UTC 12:00:03 K UTC 11:38:03 K

12. 5.4. Preliminary results (iv): GPS satellites / 13 K

14. / 13 Mr. Isaac Ramos Responsible for the design and manufacturing of the instrument Thank you!