Kongsberg Seatex

Arctic satellite navigation – lessons learned and new opportunities
by Arne Rinnan, Kongsberg Seatex AS
WORLD CLASS – through people, technology and dedication

Outline
• Introduction
• Weather conditions
• Satellite coverage
• Aurora impact
• GNSS corrections
• Observations
• New opportunities
• Conclusion
/ 2 / 20-Nov-12

INTRODUCTION
/ 3 / 20-Nov-12

4 / 20-Nov-12
Kongsberg Seatex AS

Kongsberg Seatex - Business Areas
DP Reference
Systems
Marine Seismic
Positioning and
Control
Attitude
Determination
Systems
GNSS Systems and
Projects
Load and stability
calculations

KOG Global footprint

Routes of the Viking Explorers
Viking routes
/ 7 / 20-Nov-12
Sundial: the Viking ”sextant”

Monitoring Arctic Navigation from Space
• AISSat-1 – experimental nano satellite with
AIS receiver payload
• Designed for monitoring AIS targets in arctic
regions
• Polar orbit, 600 km altitude
AISSat-1 model
• Providing data from July 2010
Project partners
/ 8 / 20-Nov-12

AISSat-1 observations, 12 July, 2010
Traffic expected to increase in the years to come

WEATHER CONDITIONS
/ 10 / 20-Nov-12

Temperatures in the Arctic
°C °F
Average July
temperatures
Average January
temperatures
-10 to +10°C 14 to 50°F
-40 to +0°C -40 to +32°F
Extreme temperatures ~ -50°C ~ -58°F
Typical GNSS antenna
specifications
-40°C
-40°F
Conclusion:
Most GNSS antennas will work fine
under almost all temperature
conditions in the Arctic
Arctic defined by the 10°C isotherm in July,
Wikipedia, 2010-08-25
/ 11 / 20-Nov-12

Iceload on GNSS Antennas
• Surprisingly little is known about the
effect of ice-load on a GNSS antenna
• Snow does probably not have any
significant effect
• A 1.25 cm wet surface ice loading will
(Ref: O’Keefe et al):
• Reduce the SNR with 3 dB
• Increase the rms position error of 1 m
• Increase the number of cycle slips
significantly
Conclusion:
Ice building up on the GNSS antenna
doesn’t make any good!
Ref: http://farm1.static.flickr.com/35/100361821_5d58d82777.jpg
/ 12 / 20-Nov-12

SATELLITE COVERAGE
/ 13 / 20-Nov-12

Significance of the Orbit Inclination Angle
• The highest latitude a satellite
can pass zenith is equal to the
orbit inclination angle
• Any GPS satellite will eventually
be visible from any position in
the Arctic
• A geostationary satellite cannot
be observed above a latitude of
about 75° with e.g. a 5°
elevation mask constraint. The
longitude position might reduce
this limit.
Glonass satellite
(64.8° inclination)
N
S
GPS satellite
(55° inclination)
GEO satellite
(0° inclination)
Glonass, GPS and GEO satellite inclination angles
/ 14 / 20-Nov-12

GPS Satellite Trajectories at Different Latitudes
Observer’s Latitude: 30°N
No GPS satellites observed below a
certain elevation in a northern
direction leads to less accuracy in
North/South direction
Observer’s Latitude: 55°N
The highest latitude where a GPS
satellites will pass zenith. Some
GPS satellites observed at a very
low elevation angle in a northern
direction
Observer’s Latitude: 75°N
No GPS satellites observed above a
certain elevation angle leads to less
accuracy in height
Plots generated by use of GeoSky II (Fugro)
/ 15 / 20-Nov-12

Visible GNSS Satellites at Different Latitudes
• HDOP and number of visible
satellites improves at high
latitudes
30°N
• PDOP peaks at high latitudes
because of fewer high
elevation satellites and
causes some degradation of
vertical accuracy
55°N
Conclusion:
Satellite coverage in Arctic is
good especially with a
combined satellite constellation
75°N
Plots generated by use of GeoSky II (Fugro)
/ 16 / 20-Nov-12

Availability of Signals from Geo Satellites
• Used for communication and
distribution of differential signals
• Some additional margin needed
due to
• roll movement
• obstructions in a southern direction
• Signal disturbance caused by high
solar activity
Conclusion:
Signals from Geo satellites will be
less available in Arctic regions
Limited visibility of Geo satellites
/ 17 / 20-Nov-12

Influence of the Ionosphere
AURORA IMPACT
/ 18 / 20-Nov-12

A Pioneer, Prof. Kristian Birkeland
• An outstanding Norwegian
physicist, born in 1867
• Demonstrated artificial polar light
in several “terella” experiments
as shown on the Norwegian ”200
kroner” banknote
• Proved several ionospheric effects
that were not verified until about
50 years later
/ 19 / 20-Nov-12

The Sun and the Sunspots
• Sunspots have been observed and counted, more or less
systematically, for thousands of years
• Sunspot activity is known to have an effect on solar wind
and conditions in the ionosphere
• Modern infrastructure is vulnerable to these effects
/ 20 / 20-Nov-12

Different Scales of Ionospheric Effects
• Large-scale:
• Basically the density of charged particles in
the ionosphere
• Medium-scale:
• F-layer patches moving over the auroral
oval
• Small-scale:
• Scintillations within the auroral oval causing
variations over a few km
The auroral oval (www.mssl.ucl.ac.uk)
/ 21 / 20-Nov-12

Effect on GPS signals - Cycle 22
”Single frequency users will have to
rely on a model of the ionospheric
group delay, and the observations
made in this trial verifies that this
model will have a very poor fit for
high latitude data.”
Northern Light
/ 22 / 20-Nov-12

The Effect of Cycle 24?
• Degraded GNSS accuracy during
”bad ionospheric weather”
• Loss of signals from
communication satellites (Geo)
during high ionospheric activity
• Increased risk of knock-out of
electronics and power due to
electromagnetic pulses like in
Quebec in 1989
Cycle 24 is reaching
its maximum!
/ 23 / 20-Nov-12

GNSS CORRECTIONS
/ 24 / 20-Nov-12

GNSS Correction Main Categories
• Local DGPS L1 Service (e.g. IALA)
• Regional SBAS services (e.g. WAAS, EGNOS, MSAS)
• Global orbit/clock services (e.g. Fugro, Veripos, C&C)
/ 25 / 20-Nov-12

Local DGPS L1 Services
IALA beacon coverage in Europe and North America
/ 26 / 20-Nov-12

Local DGPS Services in the Arctic
• Out of range of local DGPS services in most Arctic areas
• Degraded accuracy caused by ionospheric activity to be
expected
• Ionospheric activity might limit GNSS satellite tracking at the
reference stations
/ 27 / 20-Nov-12

28 / 20-Nov-12
Regional SBAS Service Coverage

The SBAS Ionospheric Model
• Calculating Ionospheric Grid
Point Delay tables
• The limitations of the method
will be density of grid points
and ground based monitoring
points
• Compensates for large-scale
and, to some extent, medium
scale effects
• Do not help much for smallscale
effects (scintillations)
/ 29 / 20-Nov-12

Regional SBAS Performance
• Most Arctic areas are outside SBAS service area
• Monitoring stations mostly deployed within service area
• Ionospheric model
• Availability of correction signals from Geo satellites limited
• Ionospheric scintillations will cause degraded accuracy and
integrity
/ 30 / 20-Nov-12

Global Orbit/Clock
• Orbit/clock corrections are global and
will not be degraded in the Arctic
• Small 2nd order effects might cause a
small accuracy degradation of
ionospheric compensation during
scintillations
• GPS L2 will be vulnerable to distortion
of the satellite signal through an
active ionosphere
• Availability of correction signals from
Fugro G2
Geo satellites will be limited
/ 31 / 20-Nov-12

Coverage of Orbit/Clock Corrections
Fugro Orbit/Clock Service Coverage in Arctic Regions
/ 32 / 20-Nov-12

Ionospheric Scintillations
OBSERVATIONS
/ 33 / 20-Nov-12

Northern Light, Oslo 3-4 August 2010
Photo: Ole Ørpen - Fugro Seastar
Northern Light prediction (yr.no)
/ 34 / 20-Nov-12

Loosing Lock on GPS L2, Tromsø
Loss of L2 signal for three high elevation GPS satellites (11, 14, 32),
Caused by ionospheric scintillations
/ 35 / 20-Nov-12

m
Iono Effect on L1 Solution, Tromsø
VBS solution, No Tromsø (700:430 km, 632:787 km, 670:1381 km)
Height Error North Error East Error
3.00
2.50
2.00
1.50
1.00
0.50
0.00
-0.50
-1.00
-1.50
-2.00
00:00:00 01:00:00 02:00:00 03:00:00
Time UTC 4 April 2010
/ 36 / 20-Nov-12

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Iono Effect on GPS Orbit/Clock Solution, Tromsø

38 / 20-Nov-12
Iono Effect on GPS/Glonass Orbit/Clock, Tromsø

NEW OPPORTUNITIES
/ 39 / 20-Nov-12

The Geopolitcal Map
October 1, 2007
/ 40 / 20-Nov-12

Galileo Galileo
/ 41 / 20-Nov-12

Galileo launch
Successful launch of the first
four Galileo IOV satellittes
2011-10-21 and 2012-10-12
Photo: ESA
42

43 / 20-Nov-12
WORLD CLASS – through people, technology and dedication

Arctic Test Bed
/ 44 / WORLD CLASS – through people, technology and dedication
20-Nov-12

45 / 20-Nov-12
Challenging Offshore Operations

MARENOR
• Project owner: EMGS
• Project management: Marintek
• Partners: Remøy, Sintef ICT,
KSAT, Telenor, UniS, Kongsberg
Seatex
• Financed by the Norwegian
Research Council
• Total budget 21 mill
• Project Period: 2012 -2015
Predicting performance of navigation and communication systems in Arctic
Regions
/ 46 / 20.11.2012

MARPOT
• Project owner: Kongsberg Seatex
• Project management: Sintef F&H
• Partners: Kongsberg Seatex,
Sintef, KSAT, Simicon, Semekor
• Reference Group: Not formally
established yet
• Financed by the Norwegian
Research Council
• Total budget 11 mill NOK wherof
45% is financed by NRC
• Project Period: 01.01.11 – 31.12.12
KV Barentshav
New technology to improve navigation safety, positioning, surveillance,
emergency response and effectiveness of infrastructure
/ 47 / 20.11.2012

Technology demonstrator KV Barentshav – Aug 2012
• 1 week demonstrations
• Organised under “MARPOT” (KSX)
• Focus on challenges of Arctic operations:
GNSS, communication, surveillance and
SIMOPS

Test equipment
• SIMOPS with new broadband and longrange
radio
•
• DPS 232 including DGNSS demodulator (
G2/RTCM)
• GNSS receiver for scintillation
measurements
• NG AIS «Super AIS» for vessel and
Aerostat/UAS
• Ice Profiler (KM Subsea)
49

Technology demonstrator KV Barentshav – Aug 2012

CONCLUSION
/ 51 / 20-Nov-12

Conclusion
• Satellite navigation will mostly work fine in Arctic areas but
there is still need for improvement
• Some degradation due to ionospheric scintillations has to be
expected but combining GPS and other GNSS solutions will
minimise the problem
• High accuracy GNSS will require better coverage by reliable
communication links
• The political significance of the Arctic is driving the
development of new technology and solutions
/ 52 / 20-Nov-12