Bathymetric mapping without GPS: Total station to your rescue

Environments where GPS signals are nonexistent or blocked, such as tunnels, bridges, and rivers, pose major challenges for navigation and precise positioning of boats.

Fortunately, a solution exists to address this issue. Discover the total station and how it works.

Total station in operation under a bridge

The total station, an excellent alternative to GPS for your bathymetry

The principle is simple yet ingenious: use a surveying instrument, the total station, to obtain precise positioning data.

Here is how it works:

Setting up the total station

The total station is positioned under the structure blocking the GPS signal (tunnel, bridge, etc.) on a point whose coordinates are already known.

This initial precision is essential and obtained by various methods.

Prism tracked by the total station

Prism tracking

A prism is then fixed on the boat’s gantry.

The total station, equipped with a motorized laser, continuously tracks this moving prism. Thanks to this tracking, it transmits the coordinates in real-time allowing more precise bathymetry.

Transmission of coordinates

The data is then transmitted. Two transmission modes are possible:

• Exploiting the existing link between the boat and its radio control. This link is used to directly transmit the prism’s positions. This is the simplest method. However, it requires proximity between the user and the total station because of the cable connection. Movement is thus restricted.

  
  

• A radio signal is emitted from the total station via a pair of Bathylink devices, which sends the prism’s coordinates to a box positioned on the boat. More complex to set up, its advantage is to allow user mobility. The signal sent is a radio signal independent of the radio control, so staying close is not necessary.

+ more infos on bathylink

Both systems can be installed on the Bathydrone range. This addition can be made after purchase and is accompanied by a user manual allowing great autonomy.

Software configuration

The Hydromagic software is reconfigured to integrate the total station. This simply requires some adjustments in the software options to guarantee optimal compatibility.

Thus, the software knows that the data does not come from a GPS signal and adapts to this constraint.

Leica station interface

Extended coverage and strong compatibility

It offers full coverage in areas where GPS signals are disrupted or even nonexistent. Thanks to its motorization, it precisely tracks the prism located on the boat despite its movements.

Its extended range of 500 meters facilitates its use and covers large areas.

This method has been tested by our experts on Leica and Trimble total stations. It also works with all stations on the market such as Topcon and Spectra, as long as they have a physical serial port and a prism tracking function.

Use of all sonars

This system is compatible with all sonars, except multibeams, and is particularly effective with side-scan sonars. This allows, for example, inspection of underwater tunnel walls where GPS signals are absent, by positioning data in real-time.

The total station technology thus represents an alternative to GPS for navigation in difficult environments.

Whether for operations under bridges, in tunnels, or other GPS-denied zones, this solution ensures precision and reliability.

With simple configuration and a detailed manual, this technology is accessible to all boat users requiring precise positioning without relying on GPS.