At the highest level, in the GERMINAL project, two Terminals are developed: the Unified Hybrid User Terminal and the IoT Software Receiver. These two systems are independent of each other, although there are some similarities between them. In this article we give a brief introduction to some aspect of the design of these terminals.
The Unified Hybrid User Terminal (thereby referred to as UHUT) is the most complex component being designed in the context of the GERMINAL project. In general terms, this terminal will have the capability to process different kinds of signals and compute a position to a considerable degree of accuracy. All the different submodules will be controlled through the use of an integrated User Interface. The signals that will be used belong to four main groups: GNSS, LEO-PNT, 5G and LEO-SOP. Apart from the legacy signals that will be collected from GNSS satellites, the rest of signals are still in early stages of deployment and/or being actively researched.
To get a general understanding of the characteristics of each signal and how they will be used, here is a short explanation for each of them:
- GNSS. Global Navigation Satellite Systems have been, for the last few decades, the main way for general users to obtain accurate positioning, navigation and timing data, with an area of use that covers most of the surface of the Earth. With different techniques, high levels of precision can be achieved. In many cases, this implies using several different signals, from the same constellation or combining signals from a combination of them. As GNSS constellations are updated and extended, new signals will become available. The UHUT will demonstrate the advantages of using some of these new signals.
- LEO-PNT. Still in early ages of development, a new European constellation of positioning satellites could soon be available for users around the globe. These satellites, located in Low Earth Orbit (LEO) as opposed to the current GNSS systems, mostly located on Medium Earth Orbit (MEO), will considerably improve upon the results that can be obtained with the current Galileo system. There’s an important consideration regarding the integration of these signals in the GERMINAL project, which is the fact that there will not be a real LEO-PNT constellation throughout the duration of the project. To tackle this issue, these signals will be entirely simulated.
- 5G. 5th generation cellular network technologies have been deployed to many areas in the world for the past few years. As the coverage increases, there’s an incentive to take advantage of all the new possibilities that these new technologies offer, such as increased bandwidth and speed, new applications for different industrial segments and, of course, positioning applications. The 5G network and signals have some qualities that make them very favorable to be combined with classic GNSS signals. Different positioning techniques and networks (namely terrestrial and non-terrestrial) will be tested throughout the project. Most of the development and testing regarding 5G technologies will be carried out by the experts at IMDEA.
- LEO-SOP. SOP stands of Signal of Opportunity, which, in general, is any application that uses signals that were created for unrelated purposes to the ones for which they are exploited. In this case, signals coming from telecommunication satellites in Low Earth Orbit will be used for positioning purposes. There is an increasing number of satellite constellations in the sky today, and it is predicted that this number will keep rising. Although the contents of these signals are private, it is possible to take measurements of some of its characteristics to estimate the position of the receiver, something for which they were not created. This technology offers some possibilities that makes it very attractive for a positioning project like GERMINAL. The bulk of the development for this technology will be done by UAB.
As mentioned earlier, each of these types of signals are received in a different submodule, with dedicated antennas and front ends. Details about the module, both in terms of hardware and software, will be laid oud in future articles. Follow us on our official accounts of LinkedIn and X if you want to stay tuned.
The work is performed in the frame of the GERMINAL (Connectivity: Enabling next generation NAV/COM Hybrid Terminal) project, funded by the European Union and contracted by EUSPA[1] (EU Agency for the Space Programme) as part of its Fundamental Elements Grants program
Footnote [1] Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Union Agency for the Space Programme (“EUSPA”) Neither the European Union nor the EUSPA can be held responsible for them.
