Celestial radio towers: the importance of satellites


The automotive industry is currently undergoing profound change. In addition to the switch to electromobility, the function of the vehicle is also undergoing fundamental changes: “The industrial sector tells us that the trend is to move from a function of a means of transport only to a function of a platform for new models economic. and services,” says Dr. Björn Gütlich, Head of the German Space Agency’s Satellite Communication Department at the German Aerospace Center (DLR) in Bonn. “It’s comparable to the transition from cellphones to smartphones.”




Lutz Meschke, Deputy Chairman of the Executive Board and Member of the Executive Board for Finance and IT of Porsche AG

And as is the case with the smartphone, seamless connectivity will also play a crucial role for the vehicles of the future. New software functions such as autonomous driving can benefit enormously from uninterrupted connectivity, for example by allowing them to send or receive warnings about dangerous places. Approaching vehicles would then still have sufficient time to adapt to the situation. “A fast, reliable and global connection to the Internet would therefore be desirable in the future,” explains Dr. Sébastien Chartier, business unit manager for high-frequency electronics at the Fraunhofer Institute for Applied Solid State Physics. “5G and 6G mobile communications will play a crucial role in this regard. In addition, new generations of satellites are also likely to play a key role in providing global coverage and ending dead zones.

Satellites are an ideal solution

DLR expert Gütlich agrees: “The existing terrestrial communications infrastructure alone is unlikely to be able to provide nationwide coverage for the foreseeable future.” As he points out, the limited radius of future 5G cells, with a radio mast at each lamppost, will force mobile communications to be supplemented with “celestial radio towers”. “Satellites are the perfect solution,” says Gütlich.

In the future, satellites will not only provide support for autonomous driving. “They could also send updated information about traffic volumes to the navigation system or new software statuses to the vehicle’s electronics in real time. Finally, space data could enable interference-free enjoyment of Internet-based in-flight entertainment services, even in remote areas with poor networks. This means that there is a wide range of uses for satellites in the automotive sector,” says Lutz Meschke, Vice President and Member of the Management Board – Finance and IT at Porsche AG and Member of the Management Board for Porsche Investment Management. Automobil Holding SE.

Geostationary Earth Orbit (GEO), 2022, Porsche AG




The main advantage of Geostationary Earth Orbit (GEO): Satellites in GEO always stay in the same position in the sky as they orbit the Earth once a day. This technology is mainly used for television, communications and weather satellites.

The prerequisite for the new services, however, is additional technology in the car, especially for receiving data from space. Dish-shaped antennas of the type used for stationary applications are out of the question for the roof of the car due to their size and shape. Instead, phased array antennas offer an option: they consist of many small antennas and special electronics that can consistently adjust the direction of transmit and receive to the position of the satellites (see box at page 53), ensuring uninterrupted data reception. Phased array antennas are also completely flat and can be integrated into a sunroof.

Satellite fleets for the new services will orbit the Earth in low Earth orbit (LEO) and geostationary Earth orbit (GEO). Closer to home, LEO satellites are up to 2,000 km from the Earth’s surface, while their GEO counterparts are stationed at an altitude of around 35,800 km and always remain above the same location. Both orbits have their specific advantages and disadvantages, especially with regard to the propagation time of the signals between the transmitter and the receiver (latency). “LEO low orbit is suitable for very fast communication due to its low latencies of around 0.04 seconds, while GEO orbit with around 0.5 seconds of latency is ideal for distributing the same content to many users,” says Walter Ballheimer, CEO of satellite manufacturer Reflex Aerospace.

Mean Earth Orbit (MEO), 2022, Porsche AG




Depending on their altitude, Medium Earth Orbit (MEO) satellites orbit the Earth a different number of times per day. Well-known examples are the satellites used for GPS, Galileo, GLONASS and BeiDou navigation systems.

LEO is already very active today: of the approximately 4,900 active satellites in orbit around the Earth, approximately 4,100 are in low Earth orbit. By comparison: there are currently only about 600 satellites in GEO orbit. And the number of LEO satellites is growing rapidly: in 2021 alone, around 1,660 of them were launched into space, compared to only around 30 satellites placed in other orbits. The enthusiasm for space is linked to the evolution of the framework conditions: whereas access to space was once reserved for States and their space agencies, more and more companies are now discovering transport and the operation of satellite fleets as a future business model.

European alternative for space

This boom has been made possible by technological advances and the growing privatization of the space industry: satellites are becoming smaller and cheaper, and the cost of putting them into orbit is also falling due to cheaper rockets and increased competition between suppliers. Elon Musk’s American space company SpaceX is by far the biggest and best known of these. By the end of 2021, it had sent nearly 1,800 LEO satellites into space for its Starlink network. They were started to bring the internet to remote areas. SpaceX also intends to provide data to trucks, boats and planes.

So far there is no European alternative to Starlink. To change this situation, the Munich rocket manufacturer Isar Aerospace, in collaboration with Reflex Aerospace and the laser communications specialist Mynaric, founded the UN:IO consortium at the end of 2021. It will receive 1.4 million euros from the EU to design a study for a dedicated European satellite constellation by 2025. Besides applications such as broadband connectivity, border surveillance and civil defence, the project UN:IO also considers connected and autonomous vehicles as potential users of its services.

Low Earth Orbit (LEO), 2022, Porsche AG




Low Earth Orbit (LEO) is home to the International Space Station (ISS) as well as numerous weather, Earth observation and communications satellites. It is currently in high demand: the vast majority of new satellites, for example those of the Starlink network, are launched in LEO.

“Services such as video telephony, streaming or even self-driving applications will only be possible when there are enough satellites in orbit,” says Ballheimer. Compared to Starlink, however, UN:IO plans to launch far fewer man-made satellites into space. “We plan to have a few hundred satellites in LEO for fast communications, and a few dozen in higher orbit for content distribution such as software updates,” Ballheimer said. “Instead of cluttering low Earth orbit with tens of thousands of satellites, we will achieve even higher communication performance by intelligently combining different orbits with just a few hundred satellites.”

Several European car manufacturers are showing keen interest in cooperating with satellite operators such as Starlink or UN:IO. This would allow them to take advantage of existing infrastructure and the expertise of space companies. Chinese automaker Geely, on the other hand, will use its own fleet of satellites. It will not only provide data to vehicles, but also provide high-precision navigation data for the company’s self-driving cars. It remains unclear whether other OEMs will follow this model. As operators of their own fleet of satellites, this would make them independent of existing companies, allow them to optimize the technology for their needs and determine their launch slots according to their needs.

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Porsche SE also invests in space: It has held a stake in Isar Aerospace since July 2021. The company develops its rockets near Munich and stands out from its competitors in particular by its high level of vertical integration: All major components are developed by Isar Aerospace itself. Isar Aerospace plans to launch the first test flight of its “Spectrum” two-stage launch vehicle from the Norwegian island of Andøya in late 2022. Later, it plans to launch small satellites into space for customers such as the UN:IO Consortium, among others, and thus help to make traveling on land a little safer and traveling more pleasant.

information

Text first published in Porsche Engineering Magazine, issue 2/2022.

Text: Ralf Kund

Copyright: All images, videos and audio files published in this article are subject to copyright. Reproduction or total or partial repetition is prohibited without the written consent of Dr. Ing. hc F. Porsche AG. Please contact [email protected] for more information.

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