quo vadis? where are we going in satellite...
TRANSCRIPT
QUO VADIS? Where are We Going in Satellite Navigation?
Guenter W. HeinHead
of Galileo
Operations
and Evolution
DepartmentEuropean
Space
Agency
PNT Symposium, Stanford, CA, USA, 9 Nov
2010
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 2
OVERVIEW
•
Systems and Architectures
•
Frequencies, Signals and Generation
•
Clocks
•
Receivers
•
Interference and Security in GNSS
•
Conclusions
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 3
CURRENT AND PLANNED SATELLITE NAVIGATION SYSTEMS
GlobalGPS
Galileo
GLONASS
COMPASS
RegionalQZSS
IRNSS
AugmentationWAAS EGNOS
MSAS GAGAN
SDCM MASS
GINS (?)
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 4
SYSTEMS AND ARCHITECTURES
•
Large number of GNSS satellites in visibility in future
•
The users will pick up the best GNSS signals based on:
Power level
Easy acquisition
Adherence to multi-constellation standards
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 5
THE MORE SATELLITES THE BETTER?
GalileoGPS GLONASS
GalileoGPS
Galileo
COMPASSGLONASS
GPSGalileo
COMPASSGLONASS
GPSGalileo
GINS
?
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 6
SBAS FUTURE: FROM SINGLE TO DUAL FREQUENCY
SBAS (EGNOS + WAAS + MSAS)
GPS Single Frequency
SBAS (EGNOS + WAAS + MSAS) GPS Dual Frequency
SBAS (GPS L1 only) SBAS (GPS L1 + GPS L5)
LPV-200
1 2
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 7
EGNOS + WAAS + MSAS + GAGAN + SDCM (GPS Dual Frequency)
+ 10 RIMS/SBAS in Southern Hemisphere
EGNOS + WAAS + MSAS + GAGAN + SDCM
(GPS Dual Frequency)
3 4
SBAS FUTURE: MULTI-REGIONAL/DUAL FREQUENCY
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 8
5 SBAS (GPS + Galileo Dual Frequency)+ RIMS in Southern Hemisphere
Almost global- except polar regions - LPV-200 availability
SBAS FUTURE: MULTI-REGIONAL/FREQ/SYSTEM
5
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 9
CAT-I L1/L5 GPS + GAL
Ava
ilabi
lity
for H
AL:
40m
VA
L:10
mM
inim
um D
epth
of C
over
age:
5
< 50%
> 50%
> 75%
> 85%
> 90%
> 95%
> 99%
> 99.5%
> 99.9%
Longitude (deg)
Latit
ude
(deg
)
L1/L5 Service / 24 GPS + 27 Galileo satellites / GEOs set to monitored / RIMS Elevation Mask 15deg / MT28 ImplementedTimestep 300s / Duration 10 days / Gridsize 2.5x2.5deg
-180 -120 -60 0 60 120 180-90
-60
-30
0
30
60
90
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 10
ARCTIC COVERAGE STUDIED IN EGEP
•
Cooperation with Canadian Space Agency on definition of navigation payload on Polar Communication & Weather (PCW) HEO Molniya type satellites
•
With only a few more RIMS LPV- 200 service can be guaranteed in the Arctic
•
Alternative orbit options like IGSO to be studied in detail as well. Artemis could be (test) candidate (re-use similar to Chinese CAPS system)
•
Option of generative payload kept open
EGNOS /PCW LPV-200 GPS L1/L5 Availability
with +10 RIMS in Arctic
Artemis visibility
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 11
OVERVIEW
•
Systems and Architectures
•
Frequencies, Signals and Generation
•
Clocks
•
Receivers
•
Interference and Security in GNSS
•
Conclusions
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 12
•
Compatibility refers to the ability of space-based positioning, navigation, and timing services to be used separately or together without interfering with each individual service or signal, and without adversely affecting national security
•
Interoperability refers to the ability of civil space-based positioning, navigation, and timing services to be used together to provide better capabilities at the user level than would be achieved by relying solely on one service or signal
COMPATIBILITY & INTEROPERABILITY
*NSPD-39: U.S. Space-Based Position, Navigation, and Timing Policy December 15, 2004
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 13
INTEROPERABILITY TODAY
Interoperability achievedInteroperability still to be achieved
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 14
•
All superpowers have or aim at their own navigation system
•
However: RNSS bands extremely scarce
RNSS portion of Radio Frequency (RF) spectrum congested
•
Especially for E1/L1 band
Bands suitable for RNSS usage very limited!
GPS
Galileo
COMPASS
QZSS
GLONASS (potentially)
CONGESTION OF E1/L1 BAND
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 15
•
Modernization of existing systems
•
Deployment of new systems
•
Intersystem interference is becoming an issue
Particularly for authorized services
Spectral separation plays a fundamental role
But also for open services
Galileo, GPS, Compass, QZSS, GLONASS (potentially) will provide interoperable signals increasing the noise floor and the consequent degradation of performance
•
L-Band may not serve all users in an ideal way (indoor/single frequency/ iono)
Spectral resources get scarce
NEW SIGNALS AND FREQUENCY BANDS MOTIVATION
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 16
•
ITU Allocation for C-Band (5010-5030) available for RNSS since WRC 2000
•
Technical difficulties and limitations in performance for that allocation–
C-band allocation adjacent to mission up-link (stop band required)
–
Narrow bandwidth (only 20 MHz minus stop band, say 15 MHz)
•
Advantages of C-
Band–
Higher resolution
–
Smaller ionospheric
impact
–
Smaller antennas at satellite
•
Drawbacks of C-Band–
Higher attenuation in atmosphere
–
Higher power at satellite or user array antennas needed
•
Studies indicate that C-band for GNSS mass market is not (yet) mature
•
C-band preferable for high-power signals and smaller antennas
•
Search for more bandwidth on C-band necessary
C-BAND DOWN-LINK FREQUENCY
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 17
•
S-Band (2483.5 –
2500 MHz) is RNSS regionally (Asia/America)
•
ITU allocation for S-Band (2483.5-2500 MHz) in Europe on agenda of WRC 2012
•
S-Band already successfully used by Chinese Beidou
since 2003
•
Indian IRNSS/GINS announced to provide navigation service in S-Band
•
S-Band already used today for communication (WLAN/Bluetooth)
•
Advantage: Synergies between navigation and communication (same front-end)
•
Disadvantage: Harsh interference environment expected
Clarity needs to be gained on the added value of combining navigation and communication in S-Band for mass market – Mission Definition
S-BAND DOWN-LINK FREQUENCY
• ITU divides world into three regions for radio spectrum management
• Region 1 • Europe, Africa, Middle East, west of the Persian
Gulf, Russia• Region 2
• American continent, some eastern Pacific Islands• Region 3
• China, Japan, East Asia and most of Oceania
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 18
ADVANCED ON-BOARD CLOCK MONITORING & CONTROL UNIT
•
To improve the stability of the on-board frequency reference and reduce its frequency jumps
•
Generates clock signal as weighted average/ensemble of all clocks rather than relying on the signal of one single master clock
DADEV Freq Jump
DADEV (2)
DADEV (3)
IEM
1x̂ D aa
Kalman Filter
Pre-processing „Laboratory Conditions“
DADEV Freq Jump
DADEV (2)
DADEV (3)
IEM
1x̂ D aa
Kalman Filter
Pre-processing „Laboratory Conditions“
Clocks Average Output signal
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 19
•
To detect signal integrity anomalies (e.g. evil waveforms) on-board and trigger alerts in real-time simplifying ground integrity checks
•
Exploits high signal-to-noise ratio available on-board
•
Signals could be monitored before transmitting antenna (1) or after that (2)
ON-BOARD SIGNAL MONITORING
Signal generationClockCoupler
Signal monitoring unit(correlator, signal measurements)Alerts
Antenna
Probeantenna
1
2
Payload
Monitoring equipment
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 20
SELF-EQUALISATION DEVICE
•
To measure signal distortions (e.g. spectrum, group delay) and generate corrections to signal generation parameters
•
Exploits high signal-to-noise ratio available on-board
•
Correction loop not necessarily in real-time (e.g. could be via ground command), as observed signal distortions are slowly drifting (hours)
ClockCoupler
Antenna
Payload
Self-Equalisation Device
Frequency generation,amplification, multiplexing
Navigation signalgeneration
Correction loop
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 21
•
To improve the ground sensor stations tracking performance, especially in presence of multipath and interference
•
Antenna array and receiver processing allow satellite tracking with narrow beams, keeping multipath and interference out, resulting in better performance and robustness of orbit determination
ADVANCED GROUND SENSOR STATIONS W/ BEAM-FORMING
Antenna array
MultipathInterference
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 22
•
Evolution in signal structure was driven in the past by
Higher accuracy, spectral separation and spectral shaping
•
Future signals shall comply with stringent spectral requirements
IMPROVEMENT OF SIGNAL CHARACTERISTICS
•
Complexity versus performance figures such as TTFF
Time to Acquisition (TTA)
Time for data demodulation
→
Need to investigate on ways to reduce TTA and time for data demodulation
Help Navigation signals could support fast acquisition
Separate, dedicated low chip rate signal
Flexibility of data message
Embedding of variable content part in addition to fixed one
Combination of the data information at symbol level instead of bit level
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 23
CURRENT AND FUTURE PAYLOADS
CURRENT FUTURE
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 24
•
On-Board Integrity Monitoring
Lower requirements on ground segment and/or user segment
•
Inter-satellite Links
Intra-system communications
Inter-satellite ranging
Autonomy
•
SBAS payloads
From transparent to generative
REBALANCE OF COMPLEXITY: GROUND TO USER SEGMENT
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 25
INTEGRITY – WHERE FROM ?
GNSS ?
SBAS ?RAIM ?
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 26
GIC / RAIM OPTIONS
•
Relative RAIM (RRAIM) relaxes TTA, but limited to GIC (GNSS Integrity Channel) performance; still requires GEO transmission
•
Absolute RAIM (ARAIM) method proposed by FAA; based on multiple solution separation; still needs:
Prototyping on real data
Threat analysis
Message consolidation
Satellite failure rate definition
•
Note: ARAIM only works with 30 or more satellites -> multi– constellation seems to be solution
RRAIM Concept
ARAIM PLs (URA 1m, bias 0.5m, GPS/Gal fail 10-4/7)
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 27
ARAIM RESULTS FOR 30 SVS URA = 0.5 m
For VAL = 35m, NDP & Acc: 97.77% coverage at 99.5% availability< 50% > 50% > 75% > 85% > 90% > 95% > 99% >99.5% >99.9%
Longitude (deg)
Latit
ude
(deg
)
URA = 0.5m, Bias = 0.5m, URE = 0.25m, rBias = 0.1m
-150 -100 -50 0 50 100 150
-80
-60
-40
-20
0
20
40
60
80
99.5% VPL - 20.46 m avg., 35m avail = 99.99%< 15 < 20 < 25 < 30 < 35 < 40 < 45 < 50 > 50
Longitude (deg)
Latit
ude
(deg
)
URA = 0.5m, Bias = 0.5m
-150 -100 -50 0 50 100 150
-80
-60
-40
-20
0
20
40
60
80
ARAIM currently predicted upon a user update rate of ~ 1hour
Reference: Eldredge, Satellite-Based Augmentation System (SBAS) Integrity Services, ICG WG-B, Munich, March 8, 2010
GPS
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 28
OVERVIEW
•
Systems and Architectures
•
Frequencies, Signals and Generation
•
Clocks
•
Receivers
•
Interference and Security in GNSS
•
Conclusions
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 29
Potential Future Technologies
For reference (Galileo)
For reference (GPS)
FUTURE TECHNOLOGIES
y (1sec) y (104sec) mass volume power
RAFS 5x10-12 5x10-14 3.2 kg 2.5 litres 30 W
PHM 1x10-12 1x10-14 19 kg 29 litres 60 W
Mini PHM 1x10-12 1x10-14 12 kg 15 litres 40 W
Caesium 3x10-12 1x10-14 10 kg 12 litres 30 W
Laser pumped RAFS
1x10-12 1x10-14 3.5 kg 3 litres 30 W
Cold Atoms /
Trapped Ions5x10-13 5x10-15 3.5 kg 3 litres 30 W
GPS RAFS 2.5x10-12 5x10-15 6.2 kg 4.8 litres 30 W
GPS and GIOVE
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 30
• Transfer of stable frequency GEO to GNSS (MEO)–
Two-way links and master clock(s) in the GEO▫
Real time
▫
Does not require clock/ambiguity parameters for orbit determination
–
Ultra stable oscillators in MEO
–
Cancellation of first order Doppler
–
Real time frequency dissemination
–
Steering of GEO frequency from the ground
• Time System–
Reference time frame in space (independent of earth)
FREQUENCY & TIME DISSEMINATION VIA GEO
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 31
OVERVIEW
•
Systems and Architectures
•
Frequencies, Signals and Generation
•
Clocks
•
Receivers
•
Interference and Security in GNSS
•
Conclusions
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 32
SEVEN TECHNOLOGY ENABLERS FOR CONSUMER GPS
Technology Consequence
A-GPS Faster, longer, higher
Massive Parallel Correlation Longer, higher with coarse-time
High Sensitivity Small, cheap antennas
Coarse Time NavigationFast TTFF without periodic
wakeup
Low TOW Decode time from weak signals
Host-based GPS Single die
RF-CMOS
* F. van Diggelen: A-GPS Assisted GPS, GNSS, and SBAS, Artech House, 2009
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 33
RECEIVER PLATFORMS
Card1995
SoftwareCode
> 2010Chip
2005-2010
Box1975-90
TodayToday
CardIntegrated2000-2005
2.5 cm
* T. Pany: Navigation Signal Processing for GNSS Software Receivers, Artech House, 2010
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 34
SOFTWARE RECEIVER APPLICATIONS
Application Justification
GPS/INS integration Easy access to tracking loops and convenient development environment
GPS reflectometry Detailed signal analysis in post processing, with arbitrary number of correlators
Indoor reference receiver
Combine indoor and outdoor signals at signal processing level yielding an accurate determination of signal attenuation
Phased array antennas Simple data flow inside the receiver of the different antennas and easy access to signals
GPS translator system Flexible receiver at server side. RF frontend as part of weapon which is finally destroyed is cheaper than complete receiver
Network based positioning of mobile phones for E911
Flexible receiver at server side
Signal analysis tool Possibility to implement dedicated analysis and monitoring algorithms with visualization capabilities
High-end receiver Possibility to implement high-end signal processing and navigation algorithms such as frequency domain signal processing, multi-correlator, vector delay lock loop etc.
* T. Pany: Navigation Signal Processing for GNSS Software Receivers, Artech House, 2010
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 35
MOORE’S LAW
* Gordon Moore
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 36
ENTERING A NEW WORLD GRAPHENE: SILICON’S SUCCESSOR?
* www.amo.de
•
Graphene is a one-atom thick sheet of carbon atoms arranged in hexagonal rings
•
Enormous potential for serving as an excellent electronic material
•
New kinds of transistors based on quantum physics
–
The electrons find no obstacles in graphene
–
The electrons roam freely across the sheet of carbon, conducting electric charge with extremely low resistance
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 37
THE FUTURE IS THE INTEGRATION OF ELECTRONICS AND PHOTONICS
* www.amo.de
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 38
OVERVIEW
•
Systems and Architectures
•
Frequencies, Signals and Generation
•
Clocks
•
Receivers
•
Interference and Security in GNSS
•
Conclusions
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 39
INTERFERENCE SOURCES
•
Unintentional –
Received power levels only –160dBW into 0dBIc antenna▫
Easy to disrupt operation▫
Shared use of ARNS band
–
Harmonics from radio sources – examples:▫
Digital television▫
Regulatory requirements insufficient to provide protection
▫
Ultra-wide band transmissions▫
Multiple sources could engender widespread interference
–
Out of band emissions from adjacent bands–
MSS emissions into L1 band
•
Intentional–
Jamming used to deny access to navigation signals–
Inter and intra-system noise
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 40
EFFECTS OF INTERFERENCE
•
Degradation of signal to noise ratio
Increase in noise level due to interference source
Lowering effective signal level
Blocking of signal in receiver’s RF and IF stages via RF filtering or signal blanking
Reduction of signal content
Noise interference
Continuous Wave (CW) interference
•
Analysis technique
Computation of
Effective C/N0
as absolute figure of merit
Degradation of C/N0
as relative figure of merit
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 41
MANAGING GNSS INTERFERENCE
•
There is a substantial amount of information on interference that must be verified, analyzed, and coordinated
•
GNSS Service Disruptions
Detection / Reporting
Information & Data Analysis
Identification / Location
Mitigation
Reference: 2Reference: 2ndnd
GNSS Vulnerabilities and Solutions Conference, GNSS Vulnerabilities and Solutions Conference, BaskaBaska, , KrkKrk
Island, Croatia, Sept. 3, 2009, Hank Island, Croatia, Sept. 3, 2009, Hank SkalskiSkalski, U.S. Dept. of Transportation, U.S. Dept. of Transportation
US Approach
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 42
ESA ACTIVITIES ON RFI DETECTION AND LOCATION
Phase A RFI Mission Study and Definition of a Payload
RFI detection, characterization, reporting and information to the GNSS users
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 43
OVERVIEW
•
Systems and Architectures
•
Frequencies, Signals and Generation
•
Clocks
•
Receivers
•
Interference and Security in GNSS
•
Conclusions
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 44
CONCLUSIONS
•
After 2020: More than 40 MEO navigation satellites in view
Higher accuracy and availability (urban areas), redundancy allows more sophisticated methods (robustness, advanced RAIM algorithms, etc.)
If signals RF compatible and
interoperable
However, further congestion of L-band increases noise floor
New frequency bands for evolution ?
C-band, S-band, other bands ?
•
Integrity: Global versus Regional Systems versus User Level
Multi-frequency/system regional SBAS can cover almost whole world and ARAIM may serve aviation
Just sophisticated RAIM for non-aviation integrity?
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 45
•
Improvements in payloads
Higher flexibility and power, on-board integrity monitoring
•
Rebalance of complexity between space and ground segment
ISL allow reduction in ground stations
Integrity moves to user level•
New space and ground clocks in development
Mini PHM, optically pumped Caesium, laser-pumped RAFs, cold atoms/trapped ions, clock ensemble in space, optical clocks
Higher accuracy (relativistic positioning needs 10-19)
However, satellite navigation needs primarily stable space clocks!
•
Geo-based Time Reference System in Space
Distribution of time from GEO to MEO may allow cheaper/simpler clocks on MEO
CONCLUSIONS
QUO VADIS? | Guenter W. Hein | Stanford’s PNT, CA, USA | 09/11/2010 | Slide 46
•
Future receiver development
Assisted GNSS
Real S/W receivers versus FPGA
Chips
Silicon > Graphene
Electronics and photonics merge in future
Radio Frequency spectrum is full
Intentional versus unintentional interference
Degradation of navigation performance
Security aspects for protected signals
Spectral overlap
CONCLUSIONS