| KEYWORD |
Bayesian Multisensor Navigation Incorporating Pseudoranges and Multipath Model
Thesis in external company 
Thesis abroad
keywords SATELLITE NAVIGATION
Reference persons FABIO DOVIS
Research Groups Navigation Signal Analysis and Simulation group (NavSAS)
Description
The thesis will be developed at The German Aerospace Center (DLR) in Oberpfaffenhofen (Munich area)
---------------------------------------------
In order to calculate one's exact position using a Global Navigation Satellite System (GNSS) all that needs to be measured is the signal transmit time between the point of observation and four or more satellites whose position are known. Three satellites are needed to find a position in the X/Y/Z domain by intersecting three circles. A fourth satellite is needed to correct for the time synchronization between the satellite and the user. The distance to each satellite can be calculated as the signals' travel times multiplied by the speed of light.
The measurement of the signal travel time is affected by several sources of errors, and in difficult environments such as indoors and urban canyons multipath effects are major error sources. The resulting erroneous distance measurements are called pseudoranges. In order for GNSS to contribute in the location estimation in these environments, errors must be eliminated as far as possible.
- Tasks
The objective of this thesis is to improve an already available Bayesian multisensor positioning system that is incorporating pseudoranges, multipath model and other sensors. Currently, standard correction models (e.g. for ionospheric, tropospheric, satellite clock drift errors) and a model for the spatial and temporal correlations of the multipath error are incorporated in a sequential positioning estimator. Preliminary models for the residual error are also implemented. A Rao-Blacwellised particle filter is used to combine the different sensors measurements.
The goal will be to improve the used transition, measurement and correction models to achieve a better performance using pseudoranges compared to when using GPS position output in both indoors and outdoors scenarios. Measurements should be collected for analysis, evaluations and testing.
See also multipath_mitigation_new_polito.doc
Required skills Knowledge of signal processing and Java is required.
Notes The German Aerospace Center (DLR) is Germany´s national research center for aeronautics and space and Germany´s space agency. Its extensive research and development work in Aeronautics, Space, Transportation and Energy is integrated into national and international cooperative venture. Approximately 5,500 people are employed in DLR´s 28 institutes and facilities at eight locations in Germany.
Student developing the thesis at DLR is supported with a grant of about 700 euros/month (net)
Interested students who want to apply for the thesis must send a CV to prof. Fabio Dovis (fabio.dovis@polito.it)
CV must include:
- List of passed exam (with grades)
- Number of exams still to be passed
- Specify if there are constraints on the expected graduation date
In case of large number of applications, students pre-selected by Politecnico teachers will have a phone interview with the researchers of DLR before the final selection
Deadline 01/01/2011
PROPONI LA TUA CANDIDATURA