How To Understand Gate

Transcription

1 Time Facility for German Galileo Test Environment GATE J. Furthner, German Aerospace Center () Folie 1, GTFS 2005 > JF

2 Content Overview of GATE Major Objectives of GATE GATE Field Service Area Functions Elements of GATE Control Segment Functional Architecture of GATE Time Facility Requirements for GATE Time Facility Physical Architecture of GATE Time Facility Controlling of GATE Time Facility Man Machine Interface Location of GATE Time Facility Folie 2 > GTFS 2005, , Dokumentname Herrsching, > Germany <2>

3 Overview of German Galileo Test Environment GATE What is GATE? Ranging system using Galileo signals Based an stationary terrestrial signal transmitters Open to any user Where is the GATE service area? Near to Munich (Berchtesgaden) Who is the customer? German Aerospace Center Status of GATE? Starting for operation in 3 rd quarter 2006 Who develops GATE? A consortium of 9 companies/universities IfEN GmbH (Poing) being the prime contractor Folie 3 > GTFS 2005, , Dokumentname Herrsching, > Germany <3>

4 GATE Consortium Folie 4 > GTFS 2005, , Dokumentname Herrsching, > Germany <4>

5 Major Objectives of GATE Signal Experiment Gain experience in building a Galileo ranging system Gain experience with new Galileo signal structure: flexible (BOC(1,1); extendible (GPS-L2C, L5); adaptable (Interference, Jamming) Receiver Testing Test facility for Galileo receivers Testing of new BOC receiver algorithms with realistic signal behaviour strength, atmospheric effects User Application Provide an environment for test of user applications Especially for hybrid GPS/Galileo applications Extendible for local applications (CAT I-III) beyond FOC Folie 5 > GTFS 2005, , Dokumentname Herrsching, > Germany <5>

6 GATE Limitations & Capabilities GATE vs. the Real Thing Constraints in geometry (DOP / Visibility) Careful choice of service area Constraints in local signal propagation effects Multipath: GTS-GMS geometry corresponds to SV-GMS worst case, but multipath due to user motion dominating effect! Geometry induced effects can be emulated Ionosphere Troposhere GATE vs. Laboratory / Simulator End to end test of receiver, including antenna Real time dynamics, instead of predefined trajectories User selectable hosting vehicle applicable for application Folie 6 > GTFS 2005, , Dokumentname Herrsching, > Germany <6>

7 GATE Field Segment in Berchtesgaden Location of Transmitter Stations: Grünstein Toter Mann Störhaus Kneifelspitze Kehlsteinhaus Jenner Location of Monitor Stations: Sulzberg Folie 7 > GTFS 2005, , Dokumentname Herrsching, > Germany <7>

8 GATE Service Area in Berchtesgaden Size: > 25 km² Performance Criteria: Min. 4 visible GTS HDOP < 2 VDOP 6-20 Infrastructure Criteria: Availability of GMS platforms Mountain area for GMS elevation Typical User Environment Available: Streets Railways Visibility Folie 8 > GTFS 2005, , Dokumentname Herrsching, > Germany <8>

9 Functions of the GATE Control Segment Hosting providing the GATE system time Monitoring controlling of the entire GATE system Archiving off all necessary data (housekeeping as well as user relevant data) Hosting operating a control centre which serves as operational node of GATE including e.g. mission planning Provide an appropriate interface to the GATE user community The main elements of the GCS are the GATE Time Facility (GTF) GATE Monitoring & Control Facility (GMCF) GATE Archiving Data Server (GADS) GATE Data Transfer Network (GDTN) GATE Mission Support Facility for Stard user (GMSF-S) Folie 9 > GTFS 2005, , Dokumentname Herrsching, > Germany <9>

10 The Elements of the GATE Control Segment GCS Mission Segment GPS / Galileo Galileo IOV satellites GPS satellites GMS Transmit Segment GTS GPF GUT Expert team Monitoring system GNSS sensor GMCF GADS GMSF-S Control Segment Master clock with hot-spare UTC() Lab NTP server GTF Operators GCC Folie 10 > GTFS 2005, , Herrsching, Dokumentname Germany > <10>

11 The Elements of the GATE Control Segment GCS GPS / Galileo Galileo IOV satellites GPS satellites Mission Segment GPF GMS GTS Transmit Segment GURx GUT User Segment Expert team Monitoring system GNSS sensor GMCF GADS GMSF-S Control Segment Master clock with hot-spare UTC Lab NTP server GTF Operators GCC Folie 11 > GTFS 2005, , Herrsching, Dokumentname Germany > <11>

12 The Elements of the GATE Control Segment GCS GATE Control Segment GMSF-S GMCF GADS GTF GATE Mission Support Facility Stard GATE Monitoring & Control Facility GATE Archiving & Data Server GATE Time Facility Located at GSOC Control Centre Located at TL Folie 12 > GTFS 2005, , Herrsching, Dokumentname Germany > <12>

13 Functional Architecture of GATE Time Facility GTF The functions of GTF are generation of reference time scale of GATE: GATE System Time GAST provision of access to GAST for other GATE elements provision of access to UTC provision of access to GPS Time GTF takes the time keeping function similar to the Precise Time Facility in Galileo. Decreasing the project costs, the GTF is hosted by the Time Laboratory (-TL) The GTF has access to clocks products (time scales) which are provided by the -TL Folie 13 > GTFS 2005, , Herrsching, Dokumentname Germany > <13>

14 GTF Functional Architecture The receivers are configured to send the following messages to the GPF: GPS observations GPS navigation messages referenced to GAST Additional Parameters through an internal OS service to GPF GAST-UTC offset rate UTC-TAI offset GATE MC-UTC() offset rate Copies of all to GPF transmitted data to GMCF Receiving transmitting configuration data for the GTF from to GMCF Synchronisation of all GATE elements via NTP protocol Folie 14 > GTFS 2005, , Herrsching, Dokumentname Germany > <14>

15 GTF Functional Architecture BIPM GPS SIS Steering to UTC UTC-UTC() UTC() correction Interface to BIPM UTC() Generation of UTC() Interface to GPS Time GAST provision UTC correction M&C data/ GPS obs Element control & interfacing GPF/GMCF GAST GAST-UTC comparison GAST correction Network synchronzation M&C data NTP synch GATE-specific operations Generation of GAST GAST Responsibility of GTF Responsibility of Time Lab Time Lab Folie 15 > GTFS 2005, , Herrsching, Dokumentname Germany > <15>

16 GTF Requirements GAST shall be produced at the GTF from a high-performance clock being the GATE master clock. The GTF shall have access to UTC. The offset between GAST UTC < 100 ns modulo 1s over any 1-year time interval within a 95% confidence level. The offset between TAI GAST < 50 ns (96%), assuming the estimation of TAI six weeks in advance. The frequency instability of GAST expressed in terms of Allan-Deviation relative to TAI shall be better than 1e-13 over s. The frequency instability of GAST expressed in terms of Allan Deviation relative to TAI shall be better than 2e-14 over 1 month. The life time of the GATE master clock shall be at least 3 years. The MTBF of the GATE master clock shall be no more than 1 failure per hours. The availability of the GTF has to be at least 98.1 percent in order to meet the overall GCS availability requirement. Folie 16 > GTFS 2005, , Herrsching, Dokumentname Germany > <16>

17 GTF Physical Architecture Detailed Availability of GTF its elements without redundancy Availability of GTF reaches not the requirement (98.1% ) without redundancy Folie 17 > GTFS 2005, , Herrsching, Dokumentname Germany > <17>

18 GTF Physical Architecture Total GAST availability without redundancy Total GAST availability with redundancy Folie 18 > GTFS 2005, , Herrsching, Dokumentname Germany > <18>

19 GTF Physical Architecture High availability of GTF needs a redundancy of single GTF elements The physical architecture of the GTF is based on COTS hardware. It consists of 2 Dell Windows Server 2003 (XEON 3 GHz, 1 GB RAM, RAID1 36 GB SCSI, 10/100/1000 Mbit Ethernet) 2 GPS time receiver Septentrio PolaRx2. Meinberg NTP/LAN Server with GPS 1PPS signal input GTF will have access to campus LAN to enable data exchange with other GATE elements. The CPU clocks of the servers will be synchronized to GAST through the NTP protocol using the campus LAN. Folie 19 > GTFS 2005, , Herrsching, Dokumentname Germany > <19>

20 GTF Physical Architecture GPS reception sub-system UTC()/GAST generationsub-system GPS RX 1 PC1 WAN I/F 1 GPF/ GMCF BIPM/IERS Interface sub-system GPS RX 2 PC2 WAN I/F 2 GPF/ GMCF UPS Equipment of Time Lab Time Lab NTP server GTF Power supply 1 PPS 10 MHz Data GPS signals Networkinterface Folie 20 > GTFS 2005, , Herrsching, Dokumentname Germany > <20>

21 GTF Physical Architecture To GATE Control Center To GATE Control Center Control Center Interface Control PC GPS Rx GPS Rx Control PC UTC() Control PC Phase microstepper Switch Phase microstepper GAST realisation subsystem GAST processing GPS Rx Clock subsystem Measuring subsystem Folie 21 > GTFS 2005, , Herrsching, Dokumentname Germany > <21>

22 PTF Physical Architecture Galileo constellation GPS constellation Galileo sensor station GST GPS SIS IF GST realization subsystem GPS/Galileo time offset processing GST processing Clock subsystem Measurement subsystem Precise Timing Facility GST-to-TAI correction Time Service Provider Folie 22 > GTFS 2005, , Herrsching, Dokumentname Germany > <22>

23 Controlling of GTF via GMCF Folie 23 > GTFS 2005, , Herrsching, Dokumentname Germany > <23>

24 Controlling of GTF via GMCF Folie 24 > GTFS 2005, , Herrsching, Dokumentname Germany > <24>

25 Controlling of GTF via GMCF Folie 25 > GTFS 2005, , Herrsching, Dokumentname Germany > <25>

26 GTF Man Machine Interface at the GMCF Folie 26 > GTFS 2005, , Herrsching, Dokumentname Germany > <26>

27 The GTF at Time Laboratory GTF UTC() Time Laboratory Folie 27 > GTFS 2005, , Herrsching, Dokumentname Germany > <27>

28 Thank you for your attention Folie 28 > GTFS 2005, , Herrsching, Dokumentname Germany > <28>