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ASM Magazine: Could you explain how C-Nav Global GNSS began and brief summary of the company history?

ED: C-Nav is a division of the C & C Technologies group of companies formed in 1992 by Thomas and Jim Chance, the sons of the remarkable John Chance who founded John E. Chance and Associates (now part of the Fugro group). C & C Technologies has grown into one of the leading international hydrographic surveying and mapping firms with offices around the world including Brazil, Mexico, UK, South Africa, Angola and Singapore.

The C-Nav Division was established in 2000 specifically to provide high-accuracy GNSS positioning solutions to the offshore and hydrographic surveying community. From the outset, C-Nav was designed for real-time Precise Point Positioning (PPP) GNSS correction data. At the time, this was a bold move by the company, years ahead of its rivals then focused on traditional Differential GPS techniques.

ASM Magazine: GNSS is now widely recognised and more countries have initiated efforts to establish their own constellations. Can you describe which satellites your equipment is able to use? Can you explain Real Time GYPSY technology. How does your company see DGNSS developing in the future?

ED: C-Nav generates and delivers real-time GNSS correctors for the US GPS and Russian GLONASS constellations and has recently enabled its solutions ready for the European Galileo system.
C-Nav is a worldwide augmentation service and provides its customers with three levels of service:

  • C-NavC1 – PPP corrected GPS
  • C-NavC2 – PPP corrected GPS + GLONASS
  • C-NavC+ – CORS VBS/RTK 3cm solutions

C-NavC1 and C-NavC2 both employ PPP solutions that solve for the source of GNSS errors rather than addressing the symptoms. Consequently, there are none of the spatial de-correlation problems associated with DGNSS techniques and this allows both the company and its customers to benefit from extraordinary accuracy right across the world.

C-NavC1 uses a proprietary version of the JPL Real Time GYPSY software first developed for the NASA space missions to deliver <10 cm real-time accuracy. C-NavC2 uses an independent proprietary PPP algorithm specially developed to cater for the latest advances in GNSS constellations including GPS L5, GLONASS G1 and G2 and Galileo. The accuracy we are able to sustain from this system is at the 5cm level.

C-Nav has invested, and continues to invest heavily in GNSS developments. We see a bright future for the professional market as GNSS moves towards the next generation of performance. The proliferation of free Satellite Based Augmentation Systems (SBAS) such as WAAS, EGNOS, MSAS and GAGAN are services we support through our range of receiver products. However, none of these services come close to delivering the precise positioning demanded by the offshore, engineering and hydrographic community.

We’re often asked why centimetric accuracy is necessary hundreds of kilometers from land. The answer is quite simple; it’s not always the accuracy per se but also the precision. Position is the single most important parameter for all work at sea. All the other remote sensing systems, all the engineering control mechanisms etc, are utterly dependent on a precise position. By removing the uncertainties from the position domain, everything else in the error budget can be confidently reduced to systematic error management of the peripheral sensors.

ASM Magazine: For which markets is your company aiming toward? Can you provide a few examples where C-Nav Global GNSS equipment is being used?

ED: C-Nav is used throughout the global offshore oil & gas industry, by the hydrographic surveying community as well as by port and harbor authorities, the dredging and aggregates industry and government departments. On land, C-Nav is used for seismic exploration, land surveying and flood mapping, geotechnical engineering and a host of other applications. The range of uses for C-Nav is extraordinary.

For example, offshore renewable energy projects are one of the more recent and exciting developments for us. C-Nav precise positioning, being what is termed an absolute technique, allows the survey and site investigation results to tie perfectly with the engineering and construction challenges posed by massive wind farms and wave energy plants.

C-Nav is also used extensively in the telecommunications industry for laying submarine cables across the deep oceans. A recent flood mapping survey in Rumania used C-Nav to significantly reduce costs by allowing the customer to quickly validate existing mapping rather than conduct a whole new survey of hundreds of square kilometers of catchment.

ASM Magazine: I came across the OSIRIS Vessel project while reviewing material. Can you tell me a bit about that project and how your equipment is being applied?

ED: Osiris Projects is a UK based company providing high quality hydrographic services across a broad spectrum of client types. They are particularly respected for their excellence in high-resolution seabed coastal mapping and geophysics. The latest addition to their fleet of vessels is SV Bibby Tethra, an exceptionally stable advanced hull design. Osiris chose C-Nav for the vessel’s primary positioning system because we were able to provide both satellite delivered C-NavC2 and GSM C-NavC+ solutions for the C-Nav3050 GNSS receiver, i.e. operating in both PPP and RTK mode for long range centimetric accuracy.

ASM Magazine: Are you a worldwide supplier of equipment? How can people access your technology if they are interested? Are there some Asian projects using C-Nav Global GNSS technology that you could elaborate upon?

ED: C-Nav is an international organization. We have ten offices and twelve distributors around the world with a further expansion underway. Accessing the technology and services is facilitated by visiting our website at where all the offices and distributors are listed for easy access. The website also provides details of the products and services with downloadable brochures and tech specs as well as many useful and informative papers on GNSS issues and guidance.

C-Nav’s profile and importance in the international GNSS community was demonstrated when it was invited to participate in the working party developing the latest Guidelines for GNSS Positioning in the Oil and Gas Industry. The guidelines are available for free download at and provide an excellent overview of the science as well as setting out the quality control and statistical requirements of the industry.

Supporting real-time correction services as well as a range of products requires a high level of customer support. C-Nav provides 24/7 customer support and help services free of charge. Additionally, we provide customer system installation and verification services, health-checks, mobilization/ demobilization services, assistance with GNSS planning and a range of aids and notices including Solar Cycle mitigation advice.

The C-Nav Division is divided up into world regions, each with a head office. Our Asia-Pacific Region is the largest region and extends from the Arabian Gulf to eastern Russia taking in Vietnam, Thailand, Indonesia, Malaysia, Papua New Guinea, Peoples Republic of China, India, Australia, Russia and all points East. The regional office is in Singapore near the airport and is managed by Kelvin Tang. Kelvin has a full business support and sales staff as well as a network of agents to manage.

Typical C-Nav activities in the Asia-Pacific Region include offshore oil & gas barge and tug operations, positioning drilling rigs, construction, inspection and diving support where precise positioning is mandatory for these vessels’ Dynamic Positioning (DP) systems. There is also a strong geophysical, hydrographic and geotechnical survey sector, as well as cable laying ships, dredgers and of course on-shore positioning activities. One of the exciting new companies blossoming in the region is Reflect Geophysical who chose C-Nav for their MV Reflect Scorpio and MV Reflect Aries research vessels.

ASM Magazine: Can you explain which correction services C-Nav Global GNSS can access? Do you see benefits in some services over others?

ED: C-Nav correction services are accessed using the C-Nav3050 range of GNSS receivers. The C-Nav3050 is a scalable unit; customers can start with a simple L1 single frequency unit and upgrade as their needs grow to SBAS enabled, RTK Extend / RTK Ultra enabled all the way to a full dual-frequency geodetic quality receiver for the high-accuracy precision real-time C-Nav subscription services. The C-Nav3050 and C-Nav7000 GNSS units can also use the free-access SBAS services such as WAAS, EGNOS etc as well as the IALA beacon coastal networks.

ASM Magazine: On the software side, what does C-Nav Global GNSS offer?

ED: Customers have a wide range of software needs but we focus on GNSS related packages. These include free start-up programs, an on-line planning tool, the C-Navigator quality and performance control and display unit and C-Monitor MS Windows based performance monitoring for generic GNSS systems. To meet the offshore industry compliance for on-line QC, we developed the C-Nav P3QC package.

ASM Magazine: Can you briefly explain how your C-NAV corrections through Inmarsat geostationary satellites operates and the benefits of this system?

ED: The C-NavC1 and C-NavC2 correctors are broadcast to the user community via a constellation of Inmarsat satellites chosen in such a way as to provide two satellites for each ocean region. These satellite constellations are uploaded from geographically diverse Land Earth Stations (LES) and configured in two networks C-Nav NET-1 and C-Nav NET-2. Users have a choice of taking corrections from either or both Nets simultaneously. In this way, C-Nav provides the 200% coverage and delivery independence that is demanded by the offshore industry.

There is no need for an additional antenna or bulky demodulator as the Inmarsat and GNSS antennas are incorporated in a 12cm antenna dome. The great benefits of using geostationary communication satellites are their world coverage and reliability. The technique used is commonly known as point-to-multipoint, i.e. broadcasts that are accessible by an unlimited number of users.

ASM Magazine: Can users of your products readily integrate positioning results with other spatial data readily – is it interoperable?

ED: The position output from C-Nav is in the common formats used by industry standard on-line acquisition packages. Integration and merging with other special data and products is a common requirement and is straightforward. The quality and performance statistics are also available in NEMA formats for those users for whom QC is important.

ASM Magazine: What is C-Scape? Is it used primarily for terrestrial applications in energy, or can it be used in other fields? Can you provide a few examples?

ED: C-Scape is a MS Windows application for the independent real-time monitoring of any Dynamic Positioning application including positioning, situational awareness and movement alerts. It was developed initially for dynamically positioned vessels such as drilling rigs and DP vessels but has the flexibility inbuilt to be adapted to a wide range of applications and is compatible with AutoCAD DXF object and MMS data file overlays. Recent C-Scape developments include a special version for monitoring safety zones as a system to provide early warning of potential incursions into danger areas.


Ed Danson is the International Sales Manager of C&C Technologies’ C-Nav Division and is based in the UK. He began his career in the land and geodetic survey profession before emigrating to the offshore industry in the late seventies, first as a freelance hydrographer then as a manager and director of some of the leading firms in the offshore industry.
Ed is a Fellow of the Chartered Institution of Civil Engineering Surveyors, serving as its President from 2006-7; Fellow of the Royal Institution of Chartered Surveyors and a Fellow of the Royal Astronomical Society. He’s active in professional matters serving on the Geospatial Engineering Board of the ICE and the IMCA Offshore Survey Division Management Committee and was on the working group developing the recently published OGP / IMCA Guidelines for GNSS Positioning in the Oil and Gas Industry.
Ed is a familiar figure in the industry and writes widely on business subjects and technology. He’s authored and co-authored text books on aspects of geospatial engineering and is an acclaimed author of narrative histories.