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(2023).
DESIGN AND TEST OF A DEPLOYABLE BROADBAND ANTENNA FOR LOW FREQUENCY SYNTHETIC APERTURE INTERFEROMETRIC RADIOMETRY FROM SMALL SATELLITES.
Proceedings of the International Astronautical Congress.
ISSN 0074-1795.
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(2018).
Channel Modelling for VHF Data Exchange System via Satellite.
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(2017).
Land-Mobile X-band Satellite Measuremensts in Norway, Experiment Description and First Results.
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Eriksen, Torkild; Bråten, Lars Erling; Haugli, Hans Christian & Storesund, Frode André
(2016).
VDE-SAT – A new maritime communications system.
Show summary
The VHF data exchange system (VDES), also referred to as the next generation of the Automatic Identification System (AIS), is under development. New frequency channels were allocated for the terrestrial component in the World Radiocommunication Conference in 2015, enabling higher data throughput and a variety of applications for the maritime community. For the satellite component (VDE-SAT), necessary to make VDES a global system, studies of the compliance with existing systems were requested by ITU.
This paper presents the first VDE-SAT downlink campaign sponsored by the European Space Agency (ESA) as well as an overview of VDES and the regulatory provisions. The objective of the ESA test campaign is to evaluate the performance of the proposed downlink waveforms and demonstrate the service concept. The campaign will be carried out by Space Norway, Kongsberg Seatex and the Norwegian Defence Research Establishment (FFI) with a VDE-SAT test transponder on-board Norsat-2. The transmissions will be received by a vessel sailing in Arctic waters and studied in terms of symbol error rates and other performance figures that will be analysed as function of waveform, communications geometry, etc.
The e-Navigation Maritime Service Portfolios of the International Maritime Organization (IMO), machine-to-machine communications, e-mail and commercial services would benefit from a VDE-SAT component. The communication needs addressed in the IMO Polar Code as well as the need for satellite communications on small vessels could be met.
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(2016).
Microdiversity on a 20 GHz slant path in Norway.
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Rytír, Martin; Grotthing, Per Arne; Tjelta, Terje; Bråten, Lars Erling & Riva, Carlo
(2015).
Three-Site Diversity on Low-Elevation 20 GHz Links in Norway.
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Bråten, Lars Erling; Sander, Jostein; Mjelde, Terje Mikal Olsen & Tjelta, Terje
(2013).
SITE DIVERSITY ON TWO SLANT PATH LINKS IN NORWAY.
Show summary
The objective of this study is to characterise the effect spatial selection diversity on two K-band space-
Earth links. An experiment designed for measuring attenuation and precipitation, and one year of
measurements are described. The 19.3 GHz beacon from the satellite Astra 4A was received
simultaneously at the sites Kjeller and Eggemoen, Norway, separated by 48 km. The measured
results at the two sites are used to characterise the achievable improvement when utilising two receive
sites and switching diversity. The measured distribution of attenuation when utilising selection diversity
is compared with single site attenuation, a significant obtainable diversity benefit is available. The one
year measured selection diversity improvement is higher than predicted by ITU-R Rec. P.618-10 for
small time percentages, corresponding to high availability requirements relevant for gateway stations.
At Eggemoen, both measured rain intensity and attenuation exceed the predicted values for small time
percentages.
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Vanhoenacker-Janvier, Danielle; Bouchard, Pierre; Bråten, Lars Erling; Fabbro, Vincent; Kourogiorgas, Charilaos & Rogers, David
(2013).
Channel Models for Aeronautical and Low Elevation Radio Links.
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(2013).
Satellite-Earth K-band Beacon Measurements at Kjeller, Norway.
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Bråten, Lars Erling & Tjelta, Terje
(2013).
Planned and early results of low elevation angle measurements at Ka-band from two projects in Norway.
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Rosello, J.; Antonio, Martellucci; Acosta, Raul; Nessel, J.; Bråten, Lars Erling & Riva, Carlo
(2012).
26-GHz data downlink for LEO satellites.
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Urke, Andreas R.; Bråten, Lars Erling & Øvsthus, Knut
(2012).
TCP challenges in hybrid military satellite networks; measurements and comparison.
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Lemorton, Joël; Fabbro, Vincent; Kourogiorgas, Charilaos; Bouchard, Pierre; Rogers, Dave & Luini, Lorenzo
[Show all 10 contributors for this article]
(2011).
Review of prediction methods for low-elevation aerospace systems and new achievements.
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(2010).
Deployable WiMAX in a Forest Area; Channel Measurements and Modelling.
Show summary
The performance of vehicle mounted WiMAX equipment has been tested in a forest environment. Path attenuation was measured at 2.3 GHz with a bandwidth of 5 MHz during the summer season. With a base station sector antenna with adjustable mast height and an omni-directional vehicle antenna at 2 m height, the received signal strength was recorded in a number of stationary positions. The excess attenuation caused by the vegetation is found to be reasonably well modelled by the current ITU-R prediction method for one terminal in woodland. The maximum attenuation was extracted from the measurements to adjust the ITU-R model to the local environment and the four base station antenna heights employed. Only moderate variation in vegetation attenuation was observed between the base station antenna heights of 3.5, 5.5, and 10.5 m, while at 14 m height the attenuation was about 5 dB lower. Shadow attenuation in dB follows a Gaussian distribution reasonably well. The highest standard deviation was observed for transmit antenna height of 14 m, where it reached 8 dB. Thus, moderate improvement in signal strength was achieved by elevating the transmit antenna, with somewhat lower average path loss at the highest antenna position. When utilising 2nd order base station antenna diversity the lowest base station antenna height benefitted most from diversity. The downlink diversity gain observed is significantly less than in the uplink. The measurements indicate that a range of about 700 m can be achieved for this setup in this environment.
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Cheffena, Michael & Bråten, Lars Erling
(2009).
Low-cost digital beacon receiver base on software defined radio.
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Carrie, Guillaume; Lacoste, Frederic; Castanet, L.; Cheffena, Michael & Bråten, Lars Erling
(2008).
A robust estimator of the dynamic characteristics of rain attenuation - Application to time series synthesis for Ka-band and Q/V-band communication systems.
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(2000).
PREDICTION OF TIME DYNAMIC RAIN ATTENUATION
AT MILLIMETRE WAVELENGTHS.
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Bråten, Lars Erling; Bjugan, Vidar; Køien, Geir M.; Tardy, Isabella; Walter, Knut Erik & Worren, Tore Arthur
(2007).
UMTS capacity considerations and recommendations on capacity-increasing techniques.
Telenor R&D.