Redundancy in Dynamic Positioning (DP) Applications based on Satellite Navigation. High Precision Navigation and Positioning Conference, June O. Ørpen, Fugro Seastar

Overview Background Satellite Navigation Corrections methods Distribution of corrections Mobile setups Global Navigation Satellite Systems (GNSS) Fugro developments Conclusions

Background Satellite navigation is the preferred position reference for today's rapidly expanding Dynamic Positioning (DP) fleet. Most DP applications require several independent positioning reference systems –Global Navigation Satellite Systems (GNSS) –Acoustic underwater systems –Local range systems Today, two Differential GPS systems are accepted if they are independent: –Independent provision of DGPS corrections. –Independent setups onboard the vessel. In addition to GPS, other GNSS are under way: –The Russian GLONASS has satellites available today, and is expanding –EU is developing Galileo –China is developing Compass

Overview Background Satellite Navigation Corrections methods Distribution of corrections Mobile setups Global Navigation Satellite Systems (GNSS) Conclusions

Orbit Error Reference Station User Clock Error In DGPS Network systems, pseudorange corrections (PRC) towards each satellite is measured at the reference station and sent to the user (Fugro HP). The orbit part of the PRC gets less accurate as distance to the reference station increases PRC Traditional DGPS NETWORK vs ORBIT/CLOCK In Orbit/Clock correction systems, the orbit and clock error for each GPS satellite is calculated centrally and sent to the user (Fugro XP) Valid world wide.

Phase Based GPS Decimeter Services Measurement accuracy: Code < 0.5 m; Phase < 1 cm Position accuracy: 10 cm Horizontal, 15 cm height (95%) Characteristics: Carrier-phase measurements Dual-frequency ionospheric delay correction Tropospheric delay estimation Network solution or Orbit/Clock Solution Less susceptible to multipath and other code tracking errors, eg during ionospheric scintillations. (ie, less jumps, this is main reason why high accuracy systems are used in DP) ~293 m (C/A code)~19 cm (carrier-phase)

FUGRO NETWORK SITES 100 Stations World Wide used in high accuracy Network Service (HP)

NASA/JPL SITES JPL Reference Stations used in high accuracy Orbit/Clock service (XP)

Phase Based Service (Top) Vs Code Based Service (Bottom) With Shadowing Drill ship at harbor. Phase based service not influenced by Shadowing/Multipath. Variations in northing are ship movements Data from the same GPS antenna and GPS receiver

Overview Background Satellite Navigation Corrections methods Distribution of corrections Mobile setups Global Navigation Satellite Systems (GNSS) Fugro developments Conclusions

Differential GNSS Distribution Geostationary Satellites are the preferred means of DGNSS corrections distribution GNSS: Global Navigation Satellite Services

NETWORK SETUP Fugro Reference Stations Orbit/Clock (XP) NCC/Hub DGPS Network (HP) NCC/Hub Multiple Uplinks to Low Power Channels Multiple Uplinks to Low Power Channels Multiple Uplinks to High Power Channels Multiple Uplinks to High Power Channels NASA/JPL Reference Stations

Fugro Broadcasts High Power (Spotbeam) Low Power (Inmarsat) Since Jan three of the Low Power Satellites also have a high power broadcast: IORH,AOREH, AORWH

AORE Low Power, AOREH High Power EASAT High Power Vessel in the North Sea

Overview Background Satellite Navigation Corrections methods Distribution of corrections Mobile setups Global Navigation Satellite Systems (GNSS) Fugro developments Conclusions

MOBILE SETUP Low Power Channel High Power Channel DGPS Network SW Engine (HP) Orbit/Clock SW Engine (XP)

Mobile Systems Kongsberg Seatex: DPS132/232, 200, 700 HP,XP,GLONASS Fugro HP 8200 HP,XP High End: Low End:

Overview Background Satellite Navigation Corrections methods Distribution of corrections Mobile setups Global Navigation Satellite Systems (GNSS) Fugro developments Conclusions

US Global Positioning System, GPS Operational Operational Satellites

Russian GLONASS GLONASS deployment milestones: –18 satellites in constellation – end 2008 –24 satellites in constellation – 2010 GLONASS STATUS AND PLANS, Veniamin Malyshev, Moscow Aviation Institute Presented at Nordic Satnav User Conference, Nov 2005,

European Satellite Navigation System, Galileo Operational 2013 (27+3 satellites) Final decision for EU funding was made Dec 2007 (€3.4 Billion)

COMPASS, Chinese Satellite Navigation System China has filed for frequencies at ITU (International Telecommunications Union) 30 Satellites MEO, km, 55 deg 5 Satellites in Geostationary Orbit, km Similar frequencies as Galileo 10 meter accuracy Have launched two satellites 2007 (GEO and MEO) Continuation of the military ”Beidou” Open Service and Authorized Service Operational 1012 (Not official) China will release details of its Compass (or Beidou 2) program “soon,” including an Interface Control Document (ICD) for the GNSS system’s open civil service and a launch schedule for additional satellites, according to representatives of the China Satellite Navigation Engineering Center speaking at the Shanghai Navigation Forum (NaviForum) in Shanghai on Thursday and Friday ( December 6-7, 2007).

Redundancy in Reference System Today GPS is used in all satellite navigation reference systems With multiple GNSS Systems, it will be possible to configure several totally independent reference system for DP applications During buildup of new GNSS systems, combined solutions will be used to take advantage of added satellites (no clear view of the sky, inospheric scintillations) GPS DGPS2 DGPS1GNSS1 DGNSS2 DGNSS1 GNSS2

Improved Availability, GPS plus GLONASS Probability that GDOP<5 for mask angle of 25  GPS only GPS + 18 GLONASS

Overview Background Satellite Navigation Corrections methods Distribution of corrections Mobile setups Global Navigation Satellite Systems (GNSS) Fugro developments Conclusions

Fugro System developments Decimeter level GPS+GLONASS –Fugro Will in the near future introduce dual frequency decimeter level accuracy GPS+GLONASS service. Transition to Dual Independent High Power –Do not require an Inmarsat terminal on board with satellite dish antenna, Fugro broadcast is received through the GPS antenna Fully independent dual broadcast in all regions of coverage. –Det Norske Veritas is verifying independence (Finished August 2008)

Coverage in Oslo 10 June 2008 (31 GPS+13 GLONASS)

Overview Background Satellite Navigation Corrections methods Distribution of corrections Mobile setups Global Navigation Satellite Systems (GNSS) Fugro developments Conclusions

Conclusions Satellite Navigation is the preferred position reference for DP Different correction generation methods (Network – Orbit/Clock) provides independent services and dual broadcasts assures independent delivery Additional Satellite Navigation Services Systems are under way: –Today about 45 satellites are available (32 GPS and 16 GLONASS) –In about 5 years 100+ satellites will be available, in four independent GNSS Fugro System Characteristics –Independence Assessment by DNV –Dual High Power Beams in all regions –GPS+GLONASS decimeter level service to be launched

Solar Cycle 24