French hydro office selects SBG Systems for inertial fleet

Shom, the French national hydrographic and oceanographic office, selected SBG Systems’ inertial navigation systems to renew its fleet.

The office chose the Navsight Apogee inertial navigation systems (INS) for its speedboats and survey vessels for both shallow and deep-water real-time bathymetric surveys and Qinertia PPK software for post-processing tasks.

As a public institution, Shom (Service hydrographique et océanographique de la marine) has three major objectives: national hydrography and cartography, defense support in hydro-oceanographic fields, and support in maritime geospatial products and services for public policies on the sea and the coast.

Shom’s fleet is based in Brest. It is composed of eleven boats, including seven speedboats, and three 59-meter long BH2 survey vessels. They operate on shallow and deep water in France, Africa, the Indian Ocean and in the Caribbean Sea. Shom also uses a fleet based in New Caledonia composed of two boats, one speedboat and a buoy-laying vessel used part of the time for hydrographic surveys.

French agency Shom’s survey vessel. (Photo: Shom)

Renewing the fleet. When it came to renewing the fleet’s INS, Shom looked at INS complying with standards set by the International Hydrographic Organization (IHO) for bathymetric surveys, with a focus on roll and heave that have the biggest impact on the multibeam echo-sounder data compensation.

After having conducted several tests in their official test zone where each element’s location is strictly and precisely known, Shom selected SBG Systems for replacement of its INS.

Shom first acquired a Navsight Ekinox (0.02° roll) for shallow-water survey in New Caledonia, and then decided to outfit the fleet in Brest with the Apogee (0.008° roll).

“The BH2 is highly versatile; it fits both deep and shallow water requirements. Having a homogenized fleet of sensors for speedboats and the BH2 is easier to maintain,” said Rémi Labonde, who is in charge of positioning and hydrographic equipment at Shom.

A seafloor survey conducted by Shom. (Image: Shom)

Navsight Apogee INS

Designed for hydrographers, the Navsight Apogee is composed of a GNSS receiver and a processing unit enabling real-time fusion of inertial and navigation data.

Navsight provides connections to external equipment such as echo sounders and computers. With its titanium enclosure, the Apogee sensor can be installed in the floodable engine compartment, close to the multibeam echo sounder.

Navsight marine solution. (Photo: SBG Systems)

Navsight Apogee is a high-performance cost-effective inertial navigation system based on state-of-the-art micro-electrical mechanical (MEMS) technology, and therefore requires no annual maintenance. The SBG solution includes free unlimited firmware updates and technical support.

Once connected through Ethernet, the Navsight web interface guides the installation. For example, a 3D view of the boat shows the entered parameters so that the user can check the installation in real-time.

The embedded filter also controls and validates lever arms and antenna alignment during this procedure, which can be a plus if the Shom needs to calibrate a new system abroad. “We are big fans of SBG’s web interface. It is modern, extremely clear, and easy to use; it really makes a difference in our team’s work,” Labonde said.

Qinertia post-processing software. Navsight Apogee INS accepts real-time corrections from real-time kinematic (RTK) or precise point positioning (PPP).

In its daily surveys, Shom uses PPP positioning, which doesn’t require installation compared to RTK. It also allows offshore surveying, or even near shore when no RTK correction is available.

SBG Systems’ in-house post-processing software Qinertia fixes data issues due to communication cut-outs. The onboard team checks the data and corrects it with Qinertia if needed.