Our Fugro Starfix®.G4 service is a GPS, GLONASS, Galileo and BeiDou positioning system that is based on orbit and clock corrections generated from Fugro's own expanded network of multiple system reference stations. Fugro Starfix®.G4 utilises Precise Point Positioning (PPP) technology, which distinguishes itself from the traditional differential approach as satellite errors are not lumped together but estimated at source on a per satellite basis. The GPS, GLONASS, Galileo and BeiDou orbit and clock corrections are computed separately, free of ionospheric and tropospheric effects.

The G4 service uses all available satellites to produce a composite position, offering a number of advantages:

• Additional satellites confirming the calculated position build confidence and reliability.
• Better resistance to ionospheric scintillation effects which tend to affect a particular part of the sky.
• Possibility to bridge periods of bad geometry for each of the separate systems.

Further positional enhancements are undertaken in our software resulting in positional accuracies of better than typically 10cm (2σ) in both the horizontal and vertical planes.

Our Fugro Starfix®.G2 service is a subset of the Fugro Starfix®.G4 service which utilises only the GPS and GLONASS satellite systems.

The Fugro Starfix®.G2+ service is an ultra-precise GPS and GLONASS Global Positioning Service, using Clock and Orbit Corrections enhanced with carrier-phase corrections from the Fugro Starfix®.G4 Network.

Fugro Starfix®.G2+ is an enhancement of our highly regarded Fugro Starfix®.G4 service and utilises advanced GNSS augmentation algorithms developed in-house by our leading GNSS augmentation experts.

The code and carrier-phase signals transmitted by GPS and GLONASS satellites are monitored globally by Fugro’s worldwide network of reference stations. These observations are processed in real-time using our proprietary algorithms to generate precise corrections which are used to augment the standard signals broadcast by GPS and GLONASS satellites. Corrections are received via seven high-powered communications satellites, providing at least two independent Fugro Starfix®.G2+ data sources. The Fugro Starfix®.G2+ satellite positioning service is particularly beneficial when seeking to measure latitude, longitude, elevation and speed with ultra-high accuracy in real-time. 

Applications

• Offshore construction, survey services, vessel monitoring and structural monitoring.
• Real-time correction of tidal changes - which impact the accuracy of seabed mapping
• Real-time monitoring of the motion of floating and fixed structures.
• The 3D accuracies of the system approach those of GNSS RTK (Real Time Kinematic) systems whilst avoiding the need for an RTK base station or local transmission link, overcoming the logistical challenges and range limitations associated with coastal RTK systems.

The resulting positional accuracies are better than 3cm and 6cm (2σ) in the horizontal and vertical planes respectively.

The Fugro Starfix®.XP2 service is a GPS and GLONASS positioning system that is based on orbit and clock corrections obtained from a third party supplier. As with Fugro Starfix®.G4,

Fugro Starfix®.XP2 also utilises Precise Point Positioning (PPP) technology, and apart from that it is 100% independent to Fugro Starfix®.G4. Further positional enhancements are undertaken in Fugro's software resulting in positional accuracies of better than 10cm and 20cm (2σ) in the horizontal and vertical planes respectively.

Our Fugro Starfix®.L1 service utilises single frequency code correction data from the Fugro network of reference stations, delivered via L-Band satellite broadcasts. These corrections, combined with a single frequency GNSS receiver are used to produce a position of high accuracy. This system can provide a positional accuracy of better than 1.0 m (2σ) horizontally at a distance of 500 km from the nearest reference station.

The Fugro StarPack unit consists of a survey grade GNSS and L-Band combined receiver and powerful processor, running Linux multi- tasking operating system. The receiver is capable of tracking all current satellite systems (GPS, GLONASS, Galileo and BeiDou).

Fugro StarPack Computational features

• Input of multiple corrections sources.
• Two independent calculation engines – developed by two different Fugro development centres.
• Multiple position calculations and outputs, including, Fugro Starfix®.G2, Fugro Starfix®.XP2 and Fugro Starfix®.L1
• New “Best Position” solution, combining all available solutions in to one, using proper weighting. “Best Position” provides increased availability and better accuracy.
• A Heading solution between two GNSS antennas.

For configuration and computational QC, the Fugro StarPack utilises a web interface which is accessed by a HTML based web browser.

Our Fugro Starfix®NG positioning software is a state-of-the-art, logical and intuitive user interface. This software comprises a common framework which handles the vessel hardware configuration, a set of associated GNSS modules to undertake the computation and QC of the data and additional modules to support customer output formats. The software is modular which allows only the modules required for the task in hand are loaded.

Fugro StarfixNG MultiFix® solution

This is a GNSS position computation and QC routines packaged in a new windows framework. The computations are based on our state-of the-art EHF GNSS algorithms which are used to compute either high precision or standard precision solutions.

Key features

• No limit on the number of correction system inputs.
• No limit on the number of positional computations.
• Each computation can employ corrections from any combination of reference stations.
• Statistical evaluation based upon IMCA recommendations.
• There is no limit on the number of position outputs.
• Fully configurable user interface, with user selected windows and displays.
• RINEX Data Logging.
• Raw GNSS and Corrections Data Logging.

Fugro Starfix®NG GNSS Tides Solution

This computes real-time observed tides from GNSS data. Taking input from Fugro Starfix® GNSS service, the module reduces positions to the vessel’s reference point by correcting for offsets and motion. This position is then heave and draft corrected to give height of calm sea above the ellipsoid. By use of a Mean Sea Surface model, the height above the ellipsoid can be reduced to a GNSS based tide value.

Key features

• The vessel GNSS antenna height is derived via one of the Fugro Starfix® high precision GNSS solutions.
• The antenna height can be smoothed online using different filters.
• Using the vessels antenna offset, motion sensor and draft, the height can be transferred to the vessel CRP to derive an ellipsoidal height for the CRP relative to the satellite positioning datum.
• The CRP can then be referenced to MSL via mean sea surface model, of which two are included in the software at present:
• The EGM2008 (earth gravitational model order 2160, global approximation of Mean Sea Surface).  The accuracy of the model is about 20cm.
• The DNSC08MSS (global Mean Sea Surface), DNSC08MDT (mean dynamic topography) MSS model from Danish National Space Centre, based on EGM2008 geoid model.