ROSA INSTRUMENT AND ITS EVOLUTION ROSA 2 GENERATION

ROSA INSTRUMENT AND ITS EVOLUTION (ROSA 2° GENERATION) A. Zin 1, S. Landenna 1, P. Ghibaudi 1, E. Mangolini 1, M. Bandinelli 2, L. Mattioni 2, V. De Cosmo 3 1 Thales Alenia Space – Italia S. p. A. , S. S. Padana Superiore 290, Vimodrone, Milano, Italy 2 IDS, Ingegneria Dei Sistemi S. p. A. – Via Livornese, 1019, 56010 Pisa, Italy 3 ASI, Agenzia Spaziale Italiana – Viale Liegi, 26, 00198 Roma, Italy Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

SUMMARY Page 2 q Context: GNSS Radio Occultation and Scatterometry / Altimetry Applications q Drivers for ROSA 2 nd Generation Development q RO & SCAT Antenna concepts q ROSA 2 nd Generation Instrument Concept Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

SCIENTIFIC CONTEXT Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

GNSS Radio Occultation Page 4 ROSA 1 st Generation Domain: Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT ( Source of media: JPL - UCAR - Wikipedia ) All rights reserved, 2008, Thales Alenia Space

GNSS Altimetry Page 5 q ROSA 2 nd Generation Domain: altimetry and scatterometry q GNSS-R altimetry: reflected signal arrives later than the direct one q Tracking of the specularly reflected coherent part of the signal allows the measurement of the arrival time difference, which is called the lapse or relative delay. Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT (Source of media: Star. Lab - ES) All rights reserved, 2008, Thales Alenia Space

GNSS Scatterometry Page 6 q Scatterometry: Scatterometry a rougher surface reflects signals from a wider region around the specular point: the glistening zone. Dimension of glistening zone, depends on roughness/sea state Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

ROSA 2 nd GENERATION MOTIVATION - DRIVERS Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

USER NEEDS… Page 8 EASIER ACCOMMODATION ON HOST SATELLITE MORE OCCULTATIONS EVENTS BETTER QUALITY OF OCCULTATIONS: sounding to down to the surface BETTER IONOSPHERIC REMOVAL INNOVATION: multipurpose instrument, modularity of applications LOW LATENCY OF RO DATA Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

USER NEEDS… Page 9 EASIER ACCOMMODATION ON HOST SATELLITE q Accommodation of ROSA was a challenging issue for host satellites not specifically conceived for RO applications, main constraint are the RO antenna dimensions. Example: Ocean. Sat II. q Reduction of mass, power, dimensions (both of receiver and antenna parts) are one of the main drivers for the development of a new generation instrument, ROSA 2 nd Generation Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

USER NEEDS… Page 10 MORE OCCULTATIONS EVENTS q The user requirement of high number of occultation events translates into multiconstellation receiver. q Currently, the rough estimate for a single constellation receiver is ~500 occ/day using rising and setting antennas q Tracking of Galileo SV (when the constellation will be fully deployed) will increase the number to ~ 1000/day q Options to track COMPASS signals, as well as GLONASS may be an interesting opportunity to be evaluated in the near future. q Unclear ICD from COMPASS and future switch to CDMA for GLONASS are uncertain aspects that need to be considered. q Impacts at Rx: Correlator technology (GALVANI, AGGA-4), Number of channels, Processing power Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

USER NEEDS… Page 11 BETTER QUALITY OF OCCULTATIONS: sounding to down to the surface BETTER IONOSPHERIC REMOVAL q This requirement translates into better SNR at correlators, good frequency stability in the time interval of an occultation, robust tracking techniques and type signals to be tracked. q On receiver side, better SNR can be achieved by considering good LNA stage on one side (i. e. noise floor reduction) and gain on the antenna side. q Frequency stability in ROSA / ROSA 2° Gen is accomplished by using high-quality USO (currently < 5. e-11 @ 50 min, 2. e-12 @ 1 s) Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

USER NEEDS… Page 12 BETTER QUALITY OF OCCULTATIONS: sounding to down to the surface BETTER IONOSPHERIC REMOVAL q Robust tracking techniques: in parallel to classical closed loop operations, in the last years the focus has been put on open-loop techniques (high-frequency raw sampling). q An implementation of this technique, based on a collaboration between Italian Univiersity (Politecnico di Torino) and TAS-I was already implemented in ROSA q Modernized signals provide the opportunity to deal with pilot signals (i. e. , signal components without data bit modulations), forgetting the current problems arosen in removal of Navigation Message Bit in Open Loop (see for example ** ). q Another important advantage of GPS Modernized signals and GALILEO Open Service is the opportunity to access the second frequency without the current drawbacks of L 2 P(Y) encription. (GPS L 2 -C, GAL E 5 a-b, GPS L 5) ** S. Sokolovskiy, C. Rocken, D. Hunt, W. Schreiner, J. Johnson, D. Masters, S. Esterhuizen, Inversion of open-loop radio occultation signals at CDAAC, Second GPS Radio Occultation Data Users Workshop, National Conference Center, Lansdowne, VA, 2005 Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

USER NEEDS… Page 13 INNOVATION q The emerging concepts in the field of remote sensign using GNSS signals is GNSS altimetry and GNSS scatterometry. q The use of an integrated instrument aimed to the fulfillment of GNSS Navigation + GNSS Radio Occultation + GNSS Scatterometry/Altimetry (NAV + RO + SCAT/ALT) is an ambitious objective that TAS-I studied in the ROSA 2 nd Gen Instrument Study q Modularity would allow, in principle, an unique design in which the RO and SCAT/ALT funtionalities are independent. NAV, of course, is the basis of the functioning. Options: q NAV + RO (single and dual-antenna) q NAV + SCAT/ALT q NAV + RO + SCAT/ALT Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

USER NEEDS… Page 14 LOW LATENCY q This issue impacts more on the ground stations displacement q At the receiver level, one of the possible improvements is to implement a mass memory in order to optimize the exchange with the satellite on-board memory Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

STUDY CONTEXT Page 15 q ROSA 2 nd Generation concept was studied in the framework of a ASI Contract in 2008 (“Opportunity Mission “), with TAS-I acting as a prime contractor q The study was done in cooperation with Italian university for the scientific aspects and user requirements (Università La Sapienza, Tor Vergata, Politecnico di Torino, CETEMPS). Industrial partner (IDS) worked on Instrument feasibility aspects, together with TAS-I q In the framework of ROSA 2° Generation study, a survey of the state of the art technology in GNSS Radio Occultation and Scatterometry from space was carried out. q This allowed the identification of ROSA 2° generation user requirements and tradeoff among various instrument concepts, q The “less mature” scatterometry part (w. r. t RO) was analysed in detail Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

ROSA 2 nd GENERATION: RO & SCAT ANTENNA CONCEPTS Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

SCATTEROMETRY ANTENNA Requirements 1 Elliptical spots to be preferred with respect to circular ones 2 Mainly interesting for altimetry applications Page 17 Due to the fact that we are working in the frame of “mission of opportunity”, also requirements relevant to antenna encumbrance and mass have been considered as “main ones” A < 0. 35 m 2 ~ (0. 6 x 0. 6 m) Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

RADIO-OCCULTATION ANTENNA Requirements Page 18 (secondary) (main) (limbo) Also in this case, requirements relevant to antenna encumbrance and mass have been considered as “main ones” Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

SCATTEROMETRY ANTENNA Baseline antenna system Page 19 The baseline configuration has been chosen having in mind the goal to minimize as much as possible antenna encumbrance (also if obviously at the cost of electric performance) § § § § § Antenna type: bi-dimensional array Maximum size: 0. 35 m 2 ( 0. 6 m x 0. 6 m) Radiating elements: patch-like antennas Bands: GPS L 1 – GALILEO E 1 BFN: Analog beam forming network Beams: 4 fixed pencil shaped beams Coverage: ± 35° off-nadir (half-cone angle) Maximum gain of each beam: 20 d. Bi Polarization: LHCP Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

RADIO-OCCULTATION ANTENNA Baseline antenna system Page 20 The baseline configuration has been chosen having in mind the goal to minimize as much as possible antenna transversal encumbrance (also if at the cost of a greater longitudinal dimension) § § § § incoming GPS signals Antenna type: 3 “combined” antennas Maximum size: 0. 6 m long, 0. 4 x 0. 4 m transv Radiating elements: 2 helices, 1 patch-like Bands: GPS L 1 & L 2, GALILEO E 1 & E 5 b Radiation pattern: main & secondary coverage Maximum gain: 12 d. Bi (main cov. ), 5 d. Bi (2 nd cov) Polarization: RHCP receiving ant 1 receiving ant 2 receiving ant 3 (diplexer) A diplexer is required at the output Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

RADIO-OCCULTATION ANTENNA Baseline antenna system stacked patch RHCP Page 21 metallic sheet (satellite body) elevation pattern azimuthal pattern Dq Df wire or printed helix dielectric support or quasi-aria Critical areas No special critical areas are identified for such baseline configuration, neither from the point of view of the design nor from the point of view of materials and manufacturing process Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

RADIO-OCCULTATION ANTENNA Preliminary simulations DM 11. 9 d. Bi Page 22 D > 5. 5 d. Bi -45° +45° DM 11. 9 d. Bi D > 0 d. Bi azimuth elevation Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

ROSA 2 nd GENERATION: RECEIVER CONCEPT Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

INSTRUMENT TRADE OFF Page 24 Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

[1] INSTRUMENT TRADE OFF ROSA reference data. Page 25 Requirement Signals # of Multi Frequency channels Up to 16 nav, Up to 16 VA occultations, up to 16 AVA occultations. RF Section Tracking Data storage Sampling On board Rate processing Comments RF Asic CL / OL ~440 MB TBC 1 -10 -50 Hz @ <200 / <50 / <, 50 Hz (space weather), >= 100 Hz OL ~220 MB TBC 1 -10 -50 Hz 200 -50 -, 1 -Hz space weather ~ 1000 occ / day expected with antenna azimuth of 45 deg, ~ 650 with azimuth of 30 deg No storage ~ 500 occ / day expected with antenna azimuth of 45 deg, ~ 300 with azimuth of 30 deg OPTION A GPS L 1 C/A+ GPS L 2 C + GALILEO (L 1, E 5 b) OPTION B GPS + GPS modernized (L 2 C + L 5 TBC) 8 nav, 8 occ (GPS) CL+ OL, RF Asic CL / OL OPTION C GPS + GPS modernized (L 2 C) 8 nav, 8 occ (GPS) RF Asic CL / OL No Occultation processing on -board. Only raw data collection. Occultation predictions necessary. 1 -10 -50 No Hz 200 -50 Occultation -, processing on 1 -Hz -board. Only space raw data weather collection. Occultation predictions necessary. ~ 500 occ / day expected with antenna azimuth of 45 deg, ~ 300 with azimuth of 30 deg Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

INSTRUMENT CONCEPT Page 26 Ø Modular Architecture allows flexibility for different instrument configurations: q NAV + RO q NAV + SCAT q NAV + RO + SCAT Ø Design “ITAR Free” Ø Main driver: accommodation on small missions ØNew technology involved: ØGALVANI correlator (AGGA-4 ? ) ØNemerix RF chip ØOMNIA mp Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

ROSA 2 nd GEN CONCEPT NAV / POD PATCH ANTENNA Page 27 ROSA SECOND GENERATION RECEIVER RADIO OCCULTATION / SPACE WEATHER VELOCITY ANTENNA SYSTEM RADIO OCCULTATION / SPACE WEATHER ANTI-VELOCITY ANTENNA SYSTEM SCATTEROMETRY / ALTIMETRY ANTENNA ARRAY Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space

Page 28 THANK YOU! Navigation Department 5 Feb. 2009 - Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space