Navigation Department 5 Feb Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space 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, Pisa, Italy 3 ASI, Agenzia Spaziale Italiana – Viale Liegi, 26, Roma, Italy

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

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

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

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 5 5 Feb Meeting ASI / EUMETSAT GNSS Altimetry  ROSA 2 nd Generationaltimetryscatterometry  ROSA 2 nd Generation Domain: altimetry and scatterometry  GNSS-R altimetry: reflected signal arrives later than the direct one  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. (Source of media: StarLab - ES)

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 6 5 Feb Meeting ASI / EUMETSAT GNSS Scatterometry 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 Meeting ASI / EUMETSAT All rights reserved, 2008, Thales Alenia Space ROSA 2 nd GENERATION MOTIVATION - DRIVERS

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

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 9 5 Feb Meeting ASI / EUMETSAT USER NEEDS…  Accommodation of ROSA was a challenging issue for host satellites not specifically conceived for RO applications, main constraint are the RO antenna dimensions. Example: OceanSat II. ROSA 2 nd Generation  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 EASIER ACCOMMODATION ON HOST SATELLITE

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

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 11 5 Feb Meeting ASI / EUMETSAT USER NEEDS…  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.  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.  Frequency stability in ROSA / ROSA 2° Gen is accomplished by using high-quality USO (currently < min, 1 s) BETTER QUALITY OF OCCULTATIONS: sounding to down to the surface BETTER IONOSPHERIC REMOVAL

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 12 5 Feb Meeting ASI / EUMETSAT USER NEEDS…  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).  An implementation of this technique, based on a collaboration between Italian Univiersity (Politecnico di Torino) and TAS-I was already implemented in ROSA  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 ** ).  Another important advantage of GPS Modernized signals and GALILEO Open Service is the opportunity to access the second frequency without the current drawbacks of L2P(Y) encription. (GPS L2-C, GAL E5a-b, GPS L5) BETTER QUALITY OF OCCULTATIONS: sounding to down to the surface ** 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 BETTER IONOSPHERIC REMOVAL

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 13 5 Feb Meeting ASI / EUMETSAT USER NEEDS… INNOVATION  The emerging concepts in the field of remote sensign using GNSS signals is GNSS altimetry and GNSS scatterometry.  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 2nd Gen Instrument Study  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:  NAV  NAV + RO (single and dual-antenna)  NAV + SCAT/ALT  NAV + RO + SCAT/ALT

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 14 5 Feb Meeting ASI / EUMETSAT USER NEEDS… LOW LATENCY  This issue impacts more on the ground stations displacement  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

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 15 5 Feb Meeting ASI / EUMETSAT STUDY CONTEXT  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  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  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.  This allowed the identification of ROSA 2° generation user requirements and tradeoff among various instrument concepts,  The “less mature” scatterometry part (w.r.t RO) was analysed in detail

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

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 17 5 Feb Meeting ASI / EUMETSAT 2 Mainly interesting for altimetry applications 1 Elliptical spots to be preferred with respect to circular ones SCATTEROMETRY ANTENNA 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 < 0.35m 2 ~ (0.6 x 0.6m) Requirements

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

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 19 5 Feb Meeting ASI / EUMETSAT SCATTEROMETRY ANTENNA 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) Baseline antenna system  Antenna type: bi-dimensional array  Maximum size:  0.35 m 2 (  0.6m x 0.6m)  Radiating elements: patch-like antennas  Bands: GPS L1 – GALILEO E1  BFN: Analog beam forming network  Beams: 4 fixed pencil shaped beams  Coverage: ±35° off-nadir (half-cone angle)  Maximum gain of each beam:  20 dBi  Polarization: LHCP

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 20 5 Feb Meeting ASI / EUMETSAT RADIO-OCCULTATION ANTENNA Baseline antenna system 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)  Antenna type: 3 “combined” antennas  Maximum size:  0.6m long,  0.4 x 0.4m transv  Radiating elements: 2 helices, 1 patch-like  Bands: GPS L1 & L2, GALILEO E1 & E5b  Radiation pattern: main & secondary coverage  Maximum gain:  12 dBi (main cov.),  5 dBi (2nd cov)  Polarization: RHCP receiving ant 1 receiving ant 2 receiving ant 3 (diplexer)  A diplexer is required at the output incoming GPS signals

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 21 5 Feb Meeting ASI / EUMETSAT 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 RADIO-OCCULTATION ANTENNA Baseline antenna system elevation patternazimuthal pattern   dielectric support or quasi-aria wire or printed helix stacked patch RHCP metallic sheet (satellite body)

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 22 5 Feb Meeting ASI / EUMETSAT -45°+45° azimuth D > 5.5 dBi elevation D M  11.9 dBi D > 0 dBi D M  11.9 dBi RADIO-OCCULTATION ANTENNA Preliminary simulations

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

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

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 25 5 Feb Meeting ASI / EUMETSAT INSTRUMENT TRADE OFF RequirementSignals# of Multi Frequency channels RF SectionTrackingData storageSampling Rate On board processing Comments OPTION AGPS L1 C/A+ GPS L2C + GALILEO (L1, E5b) Up to 16 nav, Up to 16 VA occultations, up to 16 AVA occultations. RF AsicCL / OL~440 MB TBC <200 / <50 / <, 50 Hz (space weather), >= 100 Hz OL No Occultation processing on-board. Only raw data collection. Occultation predictions necessary. ~ 1000 occ / day expected with antenna azimuth of 45 deg, ~ 650 with azimuth of 30 deg OPTION BGPS + GPS modernized (L2C + L5 - TBC) 8 nav, 8 occ (GPS) CL+ OL, RF AsicCL / OL~220 MB TBC Hz , 1-Hz space weather No Occultation processing on-board. Only raw data collection. Occultation predictions necessary. ~ 500 occ / day expected with antenna azimuth of 45 deg, ~ 300 with azimuth of 30 deg OPTION CGPS + GPS modernized (L2C) 8 nav, 8 occ (GPS) RF AsicCL / OLNo storage Hz , 1-Hz space weather No Occultation processing on-board. Only raw data collection. Occultation predictions necessary. ~ 500 occ / day expected with antenna azimuth of 45 deg, ~ 300 with azimuth of 30 deg [1] [1] ROSA reference data.

All rights reserved, 2008, Thales Alenia Space Navigation Department Page 26 5 Feb Meeting ASI / EUMETSAT INSTRUMENT CONCEPT  Modular Architecture allows flexibility for different instrument configurations:  NAV  NAV + RO  NAV + SCAT  NAV + RO + SCAT  Design “ITAR Free”  Main driver: accommodation on small missions  New technology involved:  GALVANI correlator (AGGA-4 ?)  Nemerix RF chip  OMNIA  p

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

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