The Estonian State Navy is participating in a project run by the German Space Agency, the goal of which is to create a new ground positioning system covering the Baltic Sea. The technology would ensure maritime safety for ships in the event that satellite communications, such as GPS, are disrupted or disrupted for any reason.
Today positioning is mainly based on GNSS (global navigation satellite system) on the satellites. In Western countries, four global satellite communication systems are mainly used: GPS, LONASS, BEIDOU and GALILEO. They all use fairly similar but low-power high-frequency signals. Such signals can be jammed quite easily, and Russia is doing so increasingly in the Baltic Sea region.
The aim of the project carried out by the German Space Agency is to install R-mode stations along the Baltic Sea, which would allow ships to determine their position based on radio waves emitted from certain directions in the event of an interruption in satellite communication . It is a radio navigation method based on multilateration. The Baltic Sea is a good place to build such a system, because the coast is not very far in any direction. In this way the coastal stations can cover all directions.
Stefan Gewies, a researcher at the German Aerospace Center and lead coordinator of the project, who visited Estonia as part of the project, told ERR that R mode uses much lower frequencies and more powerful signals than satellites. In other words, it would take a lot more effort to mix them.
“It doesn’t take much to interfere with GPS. All it takes is a small benchtop device which, installed in a car, can interfere, for example, with the navigation of a ferry. This is not possible with R- “Large antennas and lots of energy to interfere. Everyone would see where the signal is encrypted,” Gewies explained.
To apply R mode, the vessel must receive a radio signal from at least three stations to determine its position using triangulation. At the same time, they should be placed in as many different directions as possible from the measurement location to obtain the most accurate results. The more stations are installed around the Baltic Sea, the better.
New infrastructure does not have to be built separately
To reduce costs, the researchers want to integrate the R-mode transmitters with existing DGNSS and AIS stations, taking advantage of, among other things, their radio antennas. In principle, DGNSS stations could switch to radio navigation-based position calculation in the event of an interruption in satellite communications. R mode uses rubidium clocks to locate the ship. These clocks could be synchronized in advance via GNSS or, failing that, via a stable internet connection.
Currently, the R mode test area is located between Sweden, Poland and Germany. Now the researchers leading the project want to expand the overlap eastward and install test transmitters in Estonia and Finland as well. “In the future we will have to find out how many transmitters will be needed, because each station is a little different and the technology, antennas and the like vary,” Gewies clarified. Therefore, researchers must first familiarize themselves with each station separately.
There are two DGNSS base stations in Estonia: in Hiiumaa, Ristna and Narva Jõesuu. R Mode will initially be installed at the Hiiumaa base station. Together with the Finnish medium wave stations Turku and Porkola, they form a mathematical triangle for triangulation purposes. “Since Estonia is participating in the R-mode project for the first time, we will first test these devices with one station and then look from there,” said Andry Rütkinen, head of the state navy’s navigation unit.
For the purchase and installation of R-Mode equipment, the state fleet is preparing a public tender this year, the cost of which Rütkinen has not yet agreed to reveal, but exceeds the international limit. According to all hypotheses, the installation of the system will take place in the first quarter of 2025. The first tests will take place in the same year and the summaries will be drawn up by the end of 2026. The State will then decide how to proceed.
R mode needs to be standardized internationally
According to Stefan Gewies, applications of R mode are being studied in many parts of the world, including South Korea, Great Britain and Canada. “South Korea is one of the leading R-mode countries, because it’s also in a pretty rough neighborhood,” the researcher said. For ships to adopt R mode, it must work the same way around the world. Therefore, one of the objectives of the project is to contribute to the standardization of R mode.
According to Gewies, the Baltic Sea could become the first R-mode operating region in the world and also the largest R-mode coverage area due to favorable geographical conditions. “There’s not a big body of water here in any direction, where there’s no land for hundreds and hundreds of kilometers. That still gives us a big advantage when we apply R mode,” he noted.
The biggest challenge for wider implementation of R mode is therefore financial. The project led by Gewies receives funding from the European Union’s Baltic Sea Strategy program, but it is not enough to install R-mode devices on all beacons along the Baltic Sea. Therefore, he relies on the political will of countries. As Russia increasingly interferes with GPS in the Baltic Sea, he believes the chances of finding financing will increase.
The development of the R-mode field also faces some technical challenges that researchers are still working on. For example, the positioning accuracy of R mode is significantly lower at night than during the day. This is mainly due to changes in the ionosphere.
“If during the day the precision is 10-20 meters, at night it is 70-80 meters. In the open sea this is not a real problem. Approaching the port at night, however, requires much more precision. We are currently thinking of installing very high frequency VHF transmitters in ports with a limited range of operation,” the scientist said.
A total of 14 cooperation partners, including the Estonian Navy, participate in the ORMOBAS R-mode project from the Baltic Sea Region of the European Union. Germany, Finland, Sweden, Norway, Poland and Denmark also participate. Latvia and Lithuania participate as observer countries.
2024-01-26 09:09:00
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