GalileoNAV

GalileoNAV

Galileo is the main driver for the Europe’s technological and economical role in satellite navigation. New applications of satellite navigation which will be made possible by Galileo will have a high impact on the daily life of everybody. The DLR internal project GalileoNAV delivered scientific and technological results which significantly enhance the infrastructure and scientific knowledge base of the Institute of Communications and Navigation for participation in the Galileo development. The results of GalileoNAV have been used in external projects for ESA and GJU, e.g. the GSTB-V1 Standalone Test Case APAF (Atmospheric Performance Assessment Facility) and the GJU project GIRASOLE, and are an excellent basis for future projects, e. g. within ESA’s GNSS Evolution Program.

Highlights of the project are:

• The set up of a full operational time and clock laboratory, which enables automated clock measurements, provides reference clocks (e.g. for UTC contribution and for the GATE [Link?] system time) and enables time transfer with GPS and in future with Galileo. The clock laboratory is, with exception of PTB, unique in Germany and makes the institute one of the leading institutions in the GPS/Galileo time domain worldwide.
  
• The creation of the Experiment and Verification Network EVnet, which is a modular configurable network of HW and SW components for acquisition, archiving, processing and dissemination of GNSS data in real time according to specific user requirements. It is a unique infrastructure which will be used as a platform for the development and verification of algorithms and serve as a basic platform for the development of local elements in the new internal project GalileoADAP and external projects.
  
• The execution of the multipath channel measurement campaign in the year 2002 where a test signal was transmitted from a zeppelin flying over the Munich area, received high recognition in the public and in the scientific community. The presentation about the analyis of the measurement campaign received a best presentation award at the ION conference 2003 in Portland, US. A new model for the land mobile multipath channel was developed as result of the measurements. This model is meanwhile used as standard by ESA. The model is available for free [Link?] and was downloaded many times by scientists and engineers from universities, research institutes and industry.
  
• The Multi-Output Advanced Signal Test Environment for Receivers MASTER, which consists of two Spirent GNSS simulators for generation of GPS/Galileo navigation signals in baseband and at RF and a digital channel matrix developed by DLR. The output of the digital baseband signal and their processing in the channel matrix are unique in the world. The new innovative concept of the channel matrix was developed by DLR KN, realized together with DLR-OS and submitted for patent. Signal simulator and channel matrix are key components of an interference measurement laboratory which is currently set up. The system simulates the influence of multipath and interference signals on GNSS receivers taking into account their directional properties in a new way and enables the testing of spatial mitigation methods with help of adaptive array antennas and advanced signal processing methods.
  
• The design of a wideband Galileo antenna, which enables the reception of the whole Galileo and GPS frequency spectrum with a single antenna with good performance. This wideband element serves also as the basic element for the development of an array antenna for Galileo.
  
• New methods for multipath and interference mitigation have been developed and tested by software simulation. Spatial methods using digital beamforming techniques together with interference direction of arrival estimation show a high potential for the nearly complete elimination of disturbing signals. Additionally, estimation methods have been developed and tested by simulation, which are able to recover the line of sight signal in a multipath environment. These methods are applicable as well for single antenna as for multi-antenna configurations.
  
• Modelling of Ionospheric scintillations based on measurements with a 50 Hz GPS receiver. Ionospheric scintillations occur irregularly but can significantly disturb navigation measurements and even lead to a complete loss of signals. Amplitude and phase processors have been developed to detect and repair cycle slips due to scintillations, so that measurements can still be used, which otherwise would be lost. Thus the signal availability is increased significantly for carrier phase measurements. The modelling of scintillations in GalileoNAV is a step forward to the prediction of ionospheric scintillations. Short term prediction of ionospheric scintillations is an important issue with respect to signal integrity and continuity.

Supported by
internal

Project duration
2001-2005