Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Engineers from WorldSpace and Fraunhofer Institute Conduct Successful Tests in Satellite Time Divers

09.08.2000


WorldSpace and Fraunhofer IIS-A test Mobile Reception in Automobiles

ERLANGEN/WASHINGTON, D.C. (August 8, 2000) - A team of engineers from WorldSpace Corporation and the Fraunhofer Institut Integrierte Schaltungen have completed a successful test and demonstration of two techniques which together set the stage for WorldSpace receivers to operate in automobiles throughout the WorldSpace coverage area. These techniques are Time Diversity reception technology using current WorldSpace satellites and Multi-carrier Modulation (MCM) terrestrial rebroadcast technology for seamless reception in urban areas.

Time Diversity was achieved through the use of two broadcast channels from the AfriStar satellite, one channel delayed by 4.32 seconds with respect to the other. Time Diversity was used to eliminate blockages of the satellite transmission caused by obstacles such as bridges, trees and buildings that interrupt the line of sight to the satellite while in a moving vehicle. The method works by normally listening to the late channel and storing the early channel in a 4.32-second delayed memory. When a blockage occurs the receiver switches to the stored early channel in which the delayed early programme is precisely synchronized with the content of the blocked late channel, thus eliminating any blockage of the flow of programme content. The same process also works with data transmissions thus preventing the loss of any information content.

The MCM technology was demonstrated by conducting ground retransmissions of the same broadcast channels received from the satellite through three properly located terrestrial repeaters in Erlangen. The tests successfully demonstrated the efficacy of the MCM technique to allow seamless reception even in areas with heavy blockages of the direct signal path.

Taken together, these tests demonstrated the ability to receive the WorldSpace signal without any interruption through highway underpasses as well as in urban areas with tall buildings and structures. This is the first time that satellite Time Diversity and associated MCM retransmissions of the satellite signal have been demonstrated

"These tests represent an important step towards expanding our system capabilities to the full range of environments, whether portable, fixed or mobile throughout the WorldSpace coverage areas," said WorldSpace Chairman and CEO Noah Samara.

Additional tests and demonstrations are to be performed in Pretoria South Africa during September 2000 using a terrestrial single frequency network of MCM transmitters combined with Time Diversity satellite reception from the AfriStar satellite. Mobile receivers will compare the signal quality from the terrestrial and satellite broadcast channels and automatically select which signal best provides seamless reception between satellite reception areas and terrestrial reception areas.

About WorldSpace Corporation

Headquartered in Washington, DC, WorldSpace was founded in 1990 to provide direct satellite delivery of digital audio and multimedia services to the emerging markets of the world, including Africa, the Middle East, Asia, Latin America, and the Caribbean. The WorldSpace satellite network will consist of three geostationary satellites. The first two satellites, AfriStar and AsiaStar, were successfully launched October 28, 1998 and March 21, 2000 respectively. The third satellite, AmeriStar, will follow in 2001. Each satellite has three beams with each beam capable of delivering more than 40 channels of crystal clear audio and multimedia programming directly to portable receivers. Once completed, this unique global service will transmit quality information, education and entertainment programming to a service area that includes 4.6 billion people. For more information, visit our web site at www.worldspace.com.

About Fraunhofer IIS-A

Fraunhofer Institute for Integrated Circuits, Applied Electronics IIS-A is one of the largest R&D institutions worldwide dealing with digital broadcasting systems and audio compression technologies. About 120 scientists out of 350 employees are working in these business fields. The institute has its headquarters in Erlangen, Germany.

From the beginning, Fraunhofer IIS-A was involved in the development of the WorldSpace system including system definition and commercial uplink equipment. Fraunhofer IIS-A has also brought in its MPEG-2 Layer 3 (MP3), the audio coding standard used in the Internet. For more information, visit our web site at www.iis.fhg.de/dab

Weitere Informationen finden Sie im WWW:

Elvira Gerhäuser |

More articles from Information Technology:

nachricht UT professor develops algorithm to improve online mapping of disaster areas
29.11.2016 | University of Tennessee at Knoxville

nachricht New standard helps optical trackers follow moving objects precisely
23.11.2016 | National Institute of Standards and Technology (NIST)

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>