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GNSS Systems

Time laboratory

The working group is engaged in two main topics:

• The investigation for generation and dissemination of high precise time references for the satellite navigation application.
• Verification of signals from navigation satellite systems.

Since mid-1980s the working group examines the behavior during the generation and dissemination of high precise time references and time scales in the frame of satellite navigation. Another aspect is the development and operations of methods and facilities to validate performance parameters of satellite navigation systems but also of individual applications. For all those timing aspects, a laboratory with precise atomic clocks and dedicated measurement equipment has been provided. In-house simulators based on software and on hardware as well, are being used for time-related investigations.
Additionally, the central timing facility is being operated to synchronize all time-sensitive elements in the ground-based Galileo test environment in Berchtesgaden (GATE).

30m Dish of DLR at Weilheim

The second focal point of the working group the core element is the 30m high gain antenna (HGA) which is located in the DLR ground station in Weilheim. This antenna is being operated by the GSOC and used by the group for the verification of signals from navigation satellite systems. In 2005 the Institute of Communications and Navigation equipped the HGA with an ultramodern measurement system. Since the modernization the working group permanently analyzes satellite from global navigation systems like GPS, GLONASS und COMPASS. The institute supports the development and installation of the European satellite navigation system Galileo.

The working areas:

• Composite Clock: Development of algorithms to generate precise system time scales
• Development of algorithms to transfer timing information
• Simulation of clock errors and of synchronization errors
• Assembly and operations of ground system elements for satellite navigation
• Validation of system elements and of terminal equipment
• Investigation of interoperability issues between different GNSS (global navigation satellite systems)
• Architectural design of future satellite navigation systems
• Investigation of security aspects by using GNSS
• Supporting and advising during the definition and assembly of the ground mission segement of the Galileo satellite navigation system with respect to timing aspects
• Operations of measuring facilities to test atomic clocks (DLR time laboratory)
• Operations of a central timing facility to be used for the ground-based Galileo test environment "GATE"
• Verification of signals from navigation satellite systems
• Investigations on interference in the area of satellite navigation

Current Projects:

• Dependable Navigation (internal project)
• EGNOS (European Geostationary Navigation Overlay Service) V3 Definition Phase (ESA project)
• Galileo SMF: Galileo Signal Monitoring Facility for Galileo FOC Phase Galileo
• SEIOT: Galileo IOV Signal characterisation and Extended In-Orbit Tests
• GATE-GTF: operations of the time facility for the German Galileo Test Environment in Berchtesgaden

Finished Projects:

• ANASTASIA: combined communication and navigation equipment for civil aviation
• FSNSA: Investigation of architectures of future satellite navigation systems
• GalileoNAV: Galileo - Use, Application and verification (internal project)
• GEM: Certification of combined Galileo services
• LINA: Use of satellite navigation for precise landing approach
• MITRA: Use of Galileo for monitoring hazmat transportation
• Optical Clock: Application of noval clock technologies in the frame of satellite navigation
• PATIN: Security technologies in airport area