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Standardized
in ITU-R
P.681-7 (10/09) "Propagation data required for
the design of Earth-space land mobile telecommunication systems"
In autumn 2002 the German Aerospace Center (DLR) carried out a high resolution measurement campaign to investigate the land mobile satellite navigation multipath channel. High bandwidth navigation systems like GALILEO are strongly disturbed by reflections from structures close to the receiver. To model these effects a very high time resolution is required. Especially for the BOC (Binary Offset Carrier) signal structures the delays of echoes have to be known in ns accuracy. Approaches of the past to describe the multipath effects have resolutions of 50 ns, which is not satisfying for high precision positioning. For the measurements a Zeppelin simulated the satellite transmitting a signal down to a measurement van equipped with the receiver and various sensors. During the campaign more than 60 measurements, each lasting for about 15 minutes, were taken in several urban, suburban and rural scenarios for car and pedestrian applications.
The
following
publications describe the
measurement campaign, the data analysis and the modeling
of the land mobile channel:
One
critical scenario for navigation applications is the
urban environment with the often shadowed or blocked direct path
signal and many reflecting objects. Measurements took place in the
centre of Munich, Germany. From this data a novel model was derived
taking deterministic effects and statistical distrubtions from the
measurement into account. Using the same model structure, suburban
environments can be simulated by using appropriate scenery parameters
and the statistics gained from the measurements in
Fürstenfeldbruck, a small town near Munich. A Matlab
implementation of this model for non-commercial
research and scientific purposes is available
here: Aeronautical Channel Model: Standardized in ITU-R P.682-2 (02/07) "Propagation data required for the design of Earth-space aeronautical mobile telecommunication systems" Along with the development of GALILEO it became necessary to improve the knowledge about the aeronautical channel. Power, delay and bandwidth of reflections at aircraft structures are not modelled accurate enough for the new GNSS signal structures. For that reason the European Space Agency ESA commissioned a contract about a measurement campaign in 2002 to a research consortium: JOANNEUM RESEARCH - Austria, UNIVERSITY OF VIGO - Spain and the German Aerospace Center DLR. Only reflections which arrive shorter than the chip duration mainly contribute to the positioning error of a navigation receiver. This nature of the system made it necessary to measure the channel with an extremely high bandwidth of 100 MHz, which results in a time resolution of 20 ns, enhanced down to 1 ns by using a super-resolution algorithm.
The
following
publication describes the
measurement campaign, the data analysis and the modeling
of the aeronautical channel:
The most
critical scenario for
aeronautical applications is the "final approach", the last 3 minutes
prior to landing. From the measurements we derived a
model for this situation. Reflections at the aircraft
structure and ground reflections are modelled for two
different jet planes, a VFW 614 and an Airbus A-340. Measurements
took place at Thalerhof airport in Graz, Austria. A Matlab
implementation of this model is available here: In
case of any questions
please contact:
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