Laser Ranging to GNSS - ESA Conference Bureau

Transcription

Laser Ranging to GNSS - ESA Conference Bureau
Laser Ranging to Galileo (LR2G)
Dell’Agnello S. (INFN-LNF & ASI-CTS) and Bianco G. (ASI-CGS & INFN-LNF)
For the Research Teams of:
SCF_Lab, INFN – Laboratori Nazionali di Frascati (Rome), Italy
MLRO, ASI – Centro di Geodesia Spaziale, Matera (MT), Italy
5th Galileo International Colloquium –
Scientific and Fundamental Aspects of the Galileo Programme
Braunschweig, Germany – October 27-29, 2015
Outline
•  Satellite Laser Ranging to GNSS
•  MLRO laser station @ASI-Matera, Italy
•  SCF_Lab reflector test facility @INFN-Frascati, Italy
•  Research Project “Laser Ranging Galileo”
•  Performance of GNSS Retroreflector Arrays
•  Benefits of Laser Ranging to GNSS
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Satellite Laser Ranging (SLR) to Galileo IOV
Position/distance measurement
to cube corner retroreflectors
(CCR) with short laser pulses
and a time-of-flight technique,
time-tagging with H-maser
clocks at ground stations
MW
LRA
•  PRECISE POSITIONING
Normal points at mm level, orbits at cm level
•  ABSOLUTE ACCURACY
Defines Earth geocenter and the scale of length
•  PASSIVE, MAINTENANCE-FREE
GNSS Retroreflector Array (GRA)
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International Terrestrial Reference System (ITRS)
•  Geocenter from SLR - LAGEOS
•  Scale from SLR and VLBI
•  Orientation from VLBI
•  Distribution w/GNSS
•  Also DORIS
For Geodesy, GNSS, Gravity,
Earth Observation
LAGEOS
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SLR CONSTELLATION
Low orbits to the Moon
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Co-location of SLR & GNSS positioning
Galileo IOV
or GPS
Co-location at
GNSS satellite
(space-tie)
Laser positioning of
GNSS is referenced
to geocenter thanks
to laser ranging to
LAGEOS I & II,
whose orbits define
geocenter
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LAGEOS
SLR
532 nm
MW
Co-location at
geodesy station
(ground tie)
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WETZELL
GRAZ, …
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SCF_Lab @Frascati, Italy, next to ESA-ESRIN
“AFFILIATION”
Partnership with
NASA-SSERVI
Visit of JPL Director,
C. Elachi,
& ASI Chief Scientist,
Flamini
SCF_Lab website &
Team/authors
http://www.lnf.infn.it/
esperimenti/etrusco/
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SCF_Lab: retroreflector characterization
•  Two Optical Ground Support Equipment (OGSE)
•  SCF (top right); also lunar and altimetry
•  SCF-G (bottom right) dedicated to GNSS
•  Two AM0 sun simulators, IR thermometry
•  Optical testing: Far Field, Fizeau interferometry
•  J. Adv. Space Res. 47 (2011) 822–842
AM0 sun simulator
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Matera Laser Ranging Observatory
Led by G. Bianco, also Director of CGS, Space Geodesy Center
Telescope diameter = 1.5 m
SLR. LLR since 2010
GNSS = Global Navigation Satellite System
Towards ~100 satellites with laser retroreflectors
Indian IRNSS: ~7+4 Now ILRS tracks ~35
Japanese QZSS: 3
regional satellites
regional satellites
European Galileo:
30 satellites
IOV SCF-Tested
SCF-Tested
US GPS:
24 global
satellites
Chinese Compass/
Beidou: ~20 global,
+5 regional satellites
Russian GLONASS: 24
global satellites: SCF-Tested
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Project “Laser Ranging to Galileo” (2015-17)
•  Funded by Italian Ministry of Research (MIUR)
•  SCF_Lab characterizes on ground reflectors that
MLRO laser-tracks in orbit
•  MLRO (ASI) station upgrades
–  KHz laser, refurbished optics, improved control software
•  SCF_Lab (INFN) facility upgrade
–  Larger laser test aperture for arrays, Fizeau interferometry
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Project “Laser Ranging to Galileo”
Laser ranging and SCF-Test of
•  Galileo IOV flight model by China, property of ESA, Left
•  LAGEOS Sector EM by NASA-GSFC, Center
•  GRA = GNSS Retroreflector Array by INFN-ASI-ILRS, Right
!
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Degradations of laser return of GLO<115, GPS, GIOVE
Al back-coating of old laser retroreflector design
de-qualified by ground SCF_Lab & space ILRS measurements
Optical far field diffraction pattern (FFDP)
measured while reflector cools down in the
simulated space environment at SCF_Lab
TREFLECTOR(K)
i.e. laser return signal back on ground on an area
of few km by few km
vs. time (sec)
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SCF-Test of LAGEOS & GLO<115/GPS/GIOVE
LAGEOS IS THE ILRS
REFLECTOR STANDARD
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Laser return (FFDP) intensity
LAGEOS “Sector” EM of
NASA-GSFC SCF-Tested
@300K at INFN
LAGEOS:
unperturbed
laser return
LAGEOS: ~10% degradation
of laser return after 3 hr
exposure to Sun simulator
GLO<115/GPS/GIOVE:
~ 87% degradation
*
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Retroreflector performance in SCF_Lab simulated
“critical” space conditions
•  GNSS Critical Orbit (GCO)
•  Critical thermal degradations
of optical performance
•  Sunrise-Eclipse-Sunset
over laser reflector probes
its thermal and optical
behavior in a critical way
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GCO test: GRA thermal behavior
!
Earth
shadow
300 K
Temperature [K[
Metal (Al)
Metal (Al)
Glass (IR T)
Glass (IR T)
200 K
T = 0 hr
(sunrise)
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Time (s)
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T = 7 hr
(sunset) ½ orbit
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GCO test: GRA optical performance
No optical degradation within ±15% errors
!
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GCOTestofGalileoIOVEM,ESA-INFNcontract
CCR7
CCR1
(center)
EM ready for test in the SCF
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CCRFrontFaceIRTemperatureandGradients
Infrared Image of GALILEO IOV retroreflectors during SCF-Test at 0°C, heating phase
Optical performance
is mainly affected by
internal gradients, in
particular axial.
Front-face gradients
are also figure of
merit, in particular to
evaluate the CCR
mount conductance
and its degree of
thermal insulation
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GCO test: thermal behavior of CCR1&CCR7
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GCO test: optical performance ofCCR1
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GCO test: optical performance ofCCR7
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Performance: GRA vs. Galileo IOV CCR1, CCR7
•  GRA by INFN-ASI-ILRS: lighter/smaller than Galileo IOV
No degradations within errors (left)
•  Galileo IOV by China: performance degradations (right). But
better than old generation GLONASS/GPS/GIOVE reflectors
!
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Benefits of SLR to GNSS
•  SLR provides independent validation of GNSS orbits
–  Good radial orbit accuracy to calibrate clocks
–  Detection of systematic errors (inter-system biases)
–  Verification and diagnostics of orbit models (e.g. solar
radiation pressure, albedo, attitude effects, vs. eclipses …)
•  Combining (not just comparing) GNSS and SLR
measurements provides more accurate and stable
GNSS orbits, with absolute reference to the
geocenter and the scale of the ITRS. In fact, SLR:
–  Almost uniquely defines the geocenter of ITRF with
LAGEOS, ETALON, …
–  Gives important contribution to definition of scale together
with VLBI
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ILRS workshops on SLR tracking of GNSS
Previously:
2012, Frascati, Italy: 1-day workshop
2009 Metsovo, Greece: 5-day workshop
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Conclusion: maximizing benefits of SLR to GNSS
•  Need high-performance GRAs to get more SLR data for
better GNSS-SLR combined geodesy products
•  Need optimized ILRS stations procedures &
instrumentation for GNSS altitudes
•  Need dedicated SLR campaigns of Galileo/Multi-GNSS
•  Need all of the above for a growing GNSS
–  Ultimately, order of: 27 Galileo, 24 GLONASS, 16 GPS-III,
3 QZSS, ~10 (?) IRNSS, ~20 (?) Compass/Beidou => ~100 !
–  While now ILRS tracks ~35 satellites (lower than GNSS)
•  Galileo V2: boost performance of Retroreflector Arrays
–  Made in Europe not made in China/Russia (IOV/FOC)
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Acronyms and definitions
1. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
AM0: Air Mass Zero
ASI: Agenzia Spaziale Italiana
CCR: Cube Corner Retroreflector
ESA: European Space Agency
FFDP: Far Field Diffraction Pattern
FOC: Full Orbit Capability
GCO: GNSS Critical Orbit
GMES = Global Monitoring for
Environment and Security
9.  GNSS : Global Navigation Satellite
System
10.  GPS: Global Positioning System
11.  GRA: GNSS Retroreflector Array
12. 
13. 
14. 
15. 
16. 
17. 
18. 
19. 
20. 
21. 
22. 
23. 
24. 
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GTRF: Galileo Terrestrial Reference Frame
ILRS: International Laser Ranging Service
IOV: In Orbit Validation
IPR: Intellectual Property Rights
ITRF: International Terrestrial Reference
Frame
ITRS: International Terrestrial Reference
System
KPI: Key Performance Indicator
OCS: Optical Cross Section
LAGEOS: LAser GEOdynamics Satellite
SCF: Satellite/lunar/GNSS laser ranging and
altimetry Characterization Facility
SCF-G: Satellite laser ranging Characterization
Facility optimized for GNSS
SLR: Satellite Laser Ranging
WI: Wavefront Interferogram
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Some Reference Documents
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[RD-1] Dell’Agnello, S., et al, Creation of the new industry-standard space test of laser
retroreflectors for the GNSS and LAGEOS, J. Adv. Space Res. 47 (2011) 822–842.
[RD-2] P. Willis, Preface, Scientific applications of Galileo and other Global Navigation Satellite
Systems (II), J. Adv. Space Res., 47 (2011) 769.
[RD-3] D. Currie, S. Dell’Agnello, G. Delle Monache, A Lunar Laser Ranging Array for the 21st
Century, Acta Astron. 68 (2011) 667-680.
[RD-4] Dell’Agnello, S., et al, Fundamental physics and absolute positioning metrology with the
MAGIA lunar orbiter, Exp Astron, October 2011, Volume 32, Issue 1, pp 19-35 ASI Phase A study.
[RD-5] Dell’Agnello, S. et al, A Lunar Laser Ranging Retro-Reflector Array for NASA's
Manned Landings, the International Lunar Network and the Proposed ASI Lunar Mission
MAGIA, Proceedings of the 16th International Workshop on Laser Ranging, Space Research
Centre, Polish Academy of Sciences Warsaw, Poland, 2008.
[RD-6] International Lunar Network (http://iln.arc.nasa.gov/), Core Instrument and Communications
Working Group Final Reports.
[RD-7] Yi Mao, Max Tegmark, Alan H. Guth, and Serkan Cabi, Constraining torsion with Gravity
Probe B, Physical Review D 76, 104029 (2007).
[RD-8] March, R., Bellettini, G., Tauraso, R., Dell’Agnello, S., Constraining spacetime torsion
with the Moon and Mercury, Physical Review D 83, 104008 (2011).
[RD-9] March, R., Bellettini, G., Tauraso, R., Dell’Agnello, S., Constraining spacetime torsion
with LAGEOS, Gen Relativ Gravit (2011) 43:3099–3126.
[RD-10] ETRUSCO-2: An ASI-INFN project of technological development and “SCF-Test” of
GNSS LASER Retroreflector Arrays, S, Dell’Agnello, 3rd International Colloquium on on
Scientific and Fundamental Aspects of the Galileo Programme, Copenhagen, Denmark, August 2011
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The SCF-Test (background IPR of INFN)
•  Accurately laboratory-simulated space conditions. Concurrent/integrated:
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Dark/cold/vacuum, Sun/albedo (AM0, 1/5 AM0) and Earth (IR) simulators
Non-invasive IR and contact thermometry
Payload orbit/attitude simulation via roto-translations and thermal control
Laser interrogation and sun perturbation at varying angle
•  Deliverables / Retroreflector Key Performance Indicators (KPIs)
–  Thermal behavior
•  Thermal relaxation time of retroreflector (τCCR)
–  Optical response
•  Far Field Diffraction Pattern (FFDP)
•  (Near Field) Wavefront Fizeau Interferogram (WFI)
•  Invariant Optical Cross Section, OCS
–  OCS also in air/isothermal conditions
•  Note: reduced, partial, incomplete tests (compared to the full space SCF
environment) are randomly misleading (either optimistic or pessimistic)
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