Core Stations Jrgen Nitschke Bundesnetzagentur Germany CEPT Copenhagen

Core Stations Jürgen Nitschke, Bundesnetzagentur, Germany CEPT Copenhagen, 23 rd April 2018 www. bundesnetzagentur. de

Core Stations Why Core Stations? Core Stations play an essential role in the determination of the: • ICRF International Celestial Reference Frame • ITRF International Terrestrial Reference Frame • EOP Earth Orientation Parameters © Bundesnetzagentur 2

Core Stations Why is this data so important to Administrations and the general public? • Official Spatial Data: generated and used by administrations at state, regional and community level, • Topographic maps: contain important name and location information for environmental orientation, settlement areas, transportation systems and hydrographical networks, • Uniform Reference systems: constitute the coordinate, height and gravity basis for surveying and navigation, monitoring and exploration of global changes related to our Earth, • Coordinate Reference systems: essential for administrations, science and business, i. e. vehicle navigation, landing robots on planets is only possible with accurate navigation and measurement. © Bundesnetzagentur 3

Core Stations Geoinformation From Space to the Mobile Phone Road construction, flood protection and event planning are examples of many activities in both the public and private sectors which are based on spatial data helping to better describe the environment, climate, transportation information and economic structure. © Bundesnetzagentur 4

Core Stations Geodesy The Measurement of the Earth is a dynamic system in constant movement and subject to continuous changes such as: • Continent drifts, • Sea level changes • Speed of Earth’s rotation • Gravity (Water flow, drifting ice masses, changes in ground water) Only fixed reference systems enable administrations to measure and evaluate these changes. Governments have to take actions based on this data in order to avert damage to their country and people. © Bundesnetzagentur 5

Core Stations Geodesy The Measurement of the Earth Core Stations (VLBI and SLR) also play a vital role in providing reference data for GNSS satellites systems like Galileo, Glonass, GPS, etc. and Space missions, i. e. the determination of UT 1 (see Recommendation ITU-R TF. 460) which can be determined only on the basis of VLBI measurements. Only fixed reference systems enable administrations to measure and evaluate these changes. Governments have to take actions based on this data in order to avert damage to their country and people. © Bundesnetzagentur 6

Core Stations Regulatory Provisions (1) Although the construction of, and techniques used by, core stations are similar to those known from radio astronomy stations their scope of work differs from what is understood as radio astronomy service. However, radio astronomy stations may complement the core station network. Astronomical geodesy is not defined as a radio service in the Radio Regulations of the International Telecommunication Union. © Bundesnetzagentur 7

Core Stations Regulatory Provisions (2) The necessity for the collection of data with regard to the ICRF, ITRF and EOP and hence the importance of core stations is provided in: • Resolution A/Res/69/266 of the GA of the UN (adopted on 26. 02. 2015) • DIRECTIVE 2007/2/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 14 March 2007 establishing an Infrastructure for Spatial Information in the European Community (INSPIRE) © Bundesnetzagentur 8

Core Stations Geodetic Observatory Wettzell, Germany Water Vapor Radiometer VLBI Operations GNSSV G O S Telescope Center V G O S Telescope Hydrological Gravity TTW 1 13. 2 m Sensor Field Laboratory Array TTW 2 13. 2 m Air Space Time/Frequency Surveillance Radar Laboratory © Bundesamt für Kartographie und Geodäsie Meteorological. SLR/LLR System W L R S Sensors 2 -Color SLR System VLBI Telescope SOS–W RTW 20 m Ring Laser Gyroscope 9

Core Stations Germany Geodetic Network © Bundesamt für Kartographie und Geodäsie 10

Core Stations International Geodetic Observatory Network (2008) © Bundesamt für Kartografie und Geodäsie 11

Core Stations • Measurement of electromagnetic radiation from deep space objects (Quasars) in the frequency range 2 -14 GHz • VLBI: at least two telescopes are required for the measurement; highest requirements regarding time and frequency (df/f ~ 10 -15) • Determination of the baseline between the VLBI-stations with the recorded data after VLBI measurement at the correlater site © Bundesamt für Kartographie und Geodäsie 12

Core Stations Frequency Bands used for VLBI/VGOS Observations © Bundesnetzagentur 13

Core Stations Future IVS Network: VGOS Stations (est. 2020) © IVS 14

Core Stations Threshold interference levels for VLBI Observations (Recommendation ITU-R RA. 769) © Bundesnetzagentur Centre frequency (MHz) Threshold level (d. B(W/m 2 Hz)) 325. 3 – 217 611 – 212 1 413. 5 – 211 2 695 – 205 4 995 – 200 10 650 – 193 15 375 – 189 23 800 – 183 43 000 – 175 86 000 – 172 15

Thank you for your attention. Jürgen Nitschke Bundesnetzagentur +49 6131 18 -3040 juergen. nitschke@bnetza. de © Bundesnetzagentur 16