Transcript SLS-RFM-14-21 (Inputs proposed for PCOM Green BookV1)

SLS-RFM_14-21
Inputs proposed for PCOM Green Book
J-L. Issler
12 November 2014
London
1) Lessons from Rosetta and Mascot Proximity
Links vis-a-vis link requirements for exploration
of small bodies
rosetta
Presentation of the mission Rosetta
 Goals
:
to study :
- Comets origins
- Relations between cometary and interstelar materials
- Links with solar system origin
 Launch in march 2004
 Landing today, started this morning !
 CNES involved in lander equipements, in ground segment and
operations
land
er
3
20th Nov 2013
Parameters of the RF proximity link designed
and provided by CNES for Rosetta
RF link in S band
Full duplex
Data rate balanced between TM
TM
2033,2 MHz
TC
2208 MHz
and TC at 16 kbits/s
Protocol Request To Send
Syrlinks Equipements coming
from Myriade series ( and used
on Deep Impact mission )
4
Nota
Bene : this links has also been already used for NASA Deep Impact mission
Rosetta proximity link Architecture
Tx
TxRx
Rx Out Power : 1W RF
Consomption: 6W
Orbiter
Lander
Filtre 1
Tx/Rx1
Rx
switch
Filtre 2
Tx/Rx2
Tx switch
RF
link
Coupleur
Tx
Coupleur
Rx
Tx/Rx1
Filtre 1
Tx/Rx2
Filtre 2
5
Patch
Antenna
LHCP
The Rx signal processing ASIC
come from radiocom mass market
Support to Rosetta proximity link operations
CNES provides a technical support on TxRx equipments
and lander batteries from launch till the end of the mission.
- During post launch tests and regulary during cruise tests
before hibernation in 2011
- During post-hibernation tests in april 2014
- During the site selection phase, the landing phase and
the post-landing science phases
- Presence of a CNES team in the Lander Control Center in
Köln
6
MASCOT (DLR ) is one of the
2 landers of HAYABUSA-2 (JAXA)
MASCOT antennas mission
CNES provide RF expertise and UHF antennas
to DLR who is responsible with JAXA of the
proximity link MASCOT-HB2, heriting from
mobile phone technology
Communication architecture baseline :
►
►
►
JAXA RF-module is integrated inside MASCOT (at the sides of
the MASCOT E-Box)
Redundant transceiver with two antennas (one on the top and
on the bottom) to ensure RF-link between Mascot and HY-2
durind Surface Operation Phase
MASCOT-dedicated antenna on MESS for RF-link during
cruise
HY-2
OME-A
HY-2
OME-E
HY-2
Mascot Antenna 2
(redundancy)
RF-link used during mission
MESS-Antenna
Rx/Tx 1
Rx/Tx 2
RF Load
RF Load
RF-link used during cruise
MASCOT
CNES Antenna team development
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Mascot Antenna 1
Launch of Hayabusa 2 : very soon
These proximity links dedicated to exploration of
small bodies are not provided with accurate ranging
function
For next generation proximity links, accurate ranging function
could certainly be a need, to provide location measurements
complementary to for instance vision measurements :
This future need appear for instance when :
 a network of small landers is targeted on a small body of the solar system (
to provide a sysmical network for instance )
 primary landers could assist accuratly guided landings
 a rendez-vous or formation flying or cluster flying is required close to a small
body
Science geodesic accurate location measurements are required
GMSK-PN or Filtered (O)QPSK-PN are among possible modulations
allowing accurate ranging and simultaneously transmit medium data
rates
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Formation Flying RF sensor (FFRF) of CNES/CDTI/ESA for PRIMA
LEO mission from SSC: a miniaturized version is a possible
solution (among others) to satisfy the previously mentioned future
needs when low data rate close to 10 kbits/s are needed
■
■
■
■
■
■
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Provides relative positioning and coms for a group of spacecrafts
GPS like technology (derived from Topstar3000 GPS Rx) in S-band
Range 3m – 30 km, omnidirectional coverage
Inter-vehicle positioning thanks to QPSK-PN modulation:
 Distance: 1 cm for best SNRs and nominal multipath
 Line of Sight (LoS) : 1°for best SNRs and nominal multipath
Inter-vehicle data proximity link : 12kbps
Time synchronization
However, a communication standard used to perfom location
measurement looks preferable rather to use a navigation standard to
perfom communications, due to the range of aimed data rates for PCOM
FFRF terminal and
filter
2) Inputs on futures proximity links requirements
for the Moon
Include answers to AI_PCOM14-9 in continuation to AI_PCOM13-2/ : Devise a preliminary system architecture for
communications in the vicinity of the moon, exploiting terrestrial systems technologies wherever practicable and
propose a methodology for system design.
Continuation of document SLS-RFM_14-10
Exemple of PCOM links ( Proximity Links )
system architecture for the Moon
Lunar Relay Satellite
S-Band
[2483.5; 2500] FSS links
MHz
L-Band
[1610; 1626.5]
MHz
Rover or low
altitude module
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Lunar Relay Satellite
constellation
FSS links
RDSS /
MSS
links
Surface to
Surface
Lunar Outpost
EVA
Lunar proximity links frequencies
Lunar Orbit to Lunar Surface
390-405
MHz
2025-2110
MHz
2483.5-2500**
MHz
22.55-23.15
GHz
Lunar Surface to Lunar Orbit
435-450
MHz
1610 -1626.5**
MHz
2200-2290
MHz
25.5-27
GHz
Lunar Surface to Lunar Surface
390-405
MHz
410-420
MHz
435-450
MHz
2.4-2.48***
GHz
*25.25-25.60
GHz
*27.225-27.5
GHz
Lunar Orbit to Lunar Orbit
13.75-14.00
GHz
15.50-15.35
GHz
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Extract from Recommendation SFCG 32-2R1
COMMUNICATION FREQUENCY ALLOCATIONS
AND SHARING IN THE LUNAR REGION
** Reuse of MSS/RDSS bands in aiming at
least partly reuse of MSS/RDSS mass market
techniques and technologies available for
SatComs and SatNav.
No interferences between Earth Orbit 
surface MSS and Lunar Surface  Orbit
links has been shown by SFCG.
 At least partly reuse of OFDM-like
modulations to be explored, among other
possible modulations
*** Reuse of an IEEE 802 S-band aiming at
least partly reuse of mass market
techniques and technologies. A TBD guard
band is needed with MSS/RDSS S-band
Several Mass market chips are available to
process transmissions in both 1610-1626.5 MHz
& 2483.5-2500 MHz bands, as expected
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Titre présentation
Next generation of chip will
be more flexible (SDR, … )
Use of RDSS/MSS L+S band TT&C links
already started for space users
Exemple of the TSAT nanosatellite, carrying a
MSS/RDSS L+S band TTC link via Globalstar.
A non-modified mass market L+S band chip, Doppler
compliant, is used by the transceiver
TSAT nanosatellite, launched
the 18 april 2014 ( NASA + Air
Force Reserach Lab –KAFB +
Taylor University )
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Titre présentation
Usage planed
on board at
least 8 other
US LEO
satellites
Possible RF Architecture of international
LRSs (Lunar Relay Satellites)
MOON DTM ANTENNA FACE :
■ L/S/Ka lunar relay gimbaled antenna
■ Diplexeurs
■ Ka band Rxs (26 GHz)/Tx(23 GHz)
■ S band Rxs(2.2 GHz)/Tx(2.1 GHz)
■ L/S band repeater (1.6 GHz/2.4 GHz) or Rxs/Tx
■ NAV processor
ROUTER
EARTH DTE ANTENNA FACE:
■ Ka band earth pointed gimbaled antenna + Low Gain « fixed » Antenna
■ Diplexeurs
■ Ka band Rxs (40 GHz)/Txs(37 GHz)
Orbital architecture : See answer to AI_PCOM14-8
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Requirement issued from Science needs
To study geodesy of Moon, planets , dwarf planets and small bodies, an optional fucntion of raw
scientific location measurements is usefull, also to study a planetary ionosphere when present.
These measurements shall be both precise pseudoranges or range and precise Doppler
measurements.
For the Moon, this requirement could concern L/S et S/S and Ka/Ka bands
(Nota Bene : For Mars, this requirements could concern for PCOM S/S, X/X, Ku/Ku (and Ka/Ka bands
for links to earth, which doesn’t concern PCOM))
These optional raw scientific location measurements would be combined with the operational
location function, and could require an improved knowledge of time / phase delays of the
communication/location equipment, compared to the case of operational location when present ,
itself using PN-ranging as defined for configurations present in the draft PCOM GB.
The PCOM GB could mention this need only for Orbiter   Surface links, while 3 types of links
are needed in general ( : not only for PCOM ) :
-
Earth   Orbiter
Orbiter   Surface
Surface   Earth
These 3 types of links have the same optional scientific need of PN-ranging for raw scientific
location measurements, to « close the triangle » Earth-Orbiter-Surface
Answer to AI_PCOM14-8
Investigate the possibility of placing lunar
orbiters at orbit altitudes high enough so that
there is always an orbiter that sees a lunar
surface element and the Earth (so as to avoid
orbiter-to-orbiter links)
Lunar orbits considered for CNES RF compatibility
study of LRS with terrestrial MSS
–PlaCOM may 2011- [1]
■ Earth MSS constellation: 48 Globalstar LEO satellites in Walker constellation (1414km, 52° inclined, 8 plans of 6 satellites each).
■ Moon MSS constellation [2]: 6 satellites in 2 plans (3 satellites each), 40° inclined
(lunar poles coverage) on eccentric elliptical orbits (0.05) with semi-major axis of
7500-km (due to very irregular Moon gravity field). From [2]: global coverage is
ensured 99.9999% of the time.
Coverage Statistics of number of satellites in co-visibilities on a 10-years period
[1] : Proposal to reuse mass market MSS/RDSS frequencies and
technologies for lunar / martian future proximity links. Interference
Risk Assessment between MSS Bands systems – CNES
DCT/RF/ITP. Friday 20 may 2011 ; CCSDS Placom SIG Meeting
[2] T. A. Ely, E. Lieb, Constellations of Elliptical
Inclined Lunar Orbits Providing Polar and Global
Coverage, AAS/AIAA Astrodynamics Specialists 18
Conference, Lake Tahoe, CA, August 7-11, 2005.
Stable LRS orbits studied in [2]
« Configuration of the first 6 satellite global constellation with semimajor axis
of 7500 km. Left shows the first plane of the constellation looking face-on. Right
shows the entiere constellation looking edge-on the second plane » [2]
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AI_PCOM14-5
Investigate complexity of an
OFDM management system
to assess its relevance for
local lunar links :
Answer to be provided the 12
november 2014