Leeheim Space Radio Monitoring Station
- Functions of the Leeheim Space Radio Monitoring Station
- Antennas 1 and 4
- Detection of up-link Interferers
- Services to customers external to Federal Network Agency
The Leeheim space radio monitoring station is located at the river Rhine approximately 35 kilometres south-west of Frankfurt/Main. Its fully steerable parabolic reflector antennas of up to 12 metres in diameter are pointed towards satellites in space. These antennas do not serve commercial transmission purposes, but form the heart of an installation used to observe the frequency spectrum allocated to space radio services and to detect interference on satellite frequencies.
The number of satellites in orbit is rising and consequently the demand for satellite radio frequencies for telecommunications is increasing. Forward-looking planning of frequency utilization is therefore assuming more and more importance. The danger of radio interference is increasing too. The possibility to rapidly localise sources of interference by technical means is of great significance in economic terms to both operators and users.
In the Federal Republic of Germany the Federal Network Agency for Electricity, Gas, Telecommunications, Post and Railway is the competent body for radio monitoring. The Federal Network Agency space radio monitoring station at Leeheim is charged through national legislation and by international agreements with monitoring the space radio services. This comprises a variety of tasks such as the localization and elimination of radio interference in satellite communications.
Functions of the Leeheim Space Radio Monitoring Station
- As an aid for planning and coordination,
General orbit observations reveal the actual use of the frequency spectrum for space services, including transponder occupancy of satellites and the population in the geostationary orbit.
Specific frequency occupancy observations, for example in conjunction with radio frequency coordination procedures, enable potential interference to be detected early during the planning stage of satellite systems.
Field experiments can support the optimization of theoretical models that facilitate the shared use of frequencies by space and terrestrial services.
- As a tool for satellite positioning and operation
Pre-launch observations on telemetry and tracking frequencies guarantee the successful positioning of geostationary satellites.
Satellite transponder occupancy monitoring assures, from an authority point of view, that the satellite operation happens as advance published, coordinated and notified internationally.
Interference handling detects sources of harmful interference which otherwise would continue to hinder proper operation of satellite or terrestrial radio services.
Antennas 1 and 4
Antenna 1, a 12 m parabolic reflector antenna, is, in principle, a broadband antenna designed to cover the 1 - 13 GHz frequency range. Rather narrow frequency band units with optimized characteristics at 1.5 - 1.8 and 2.1 - 2.3 GHz as well as at 10.7 - 12.75 GHz, together with a high accuracy for angle measurements, are a pre-requisite for the so-called monopulse tracking for high precision antenna pointing. An adjustable deflecting mirror as well as a slide mechanism facilitate switching between the bands.
The rather wide 4.3 - 8.5 GHz frequency slot of Antenna 1 does not allow for monopulse tracking. However, in addition the Antennas 1, 3 and 4 dispose of accurate computer controlled position and polarization tracking capabilities in all their frequency bands.
Antenna 2 is purposely pointed manually only.
Due to the capability of sufficient angular velocities in azimuth and elevation, all the antennas can cope with the tracking of any non-geostationary satellite.
The station can measure the emission characteristics such as:
- Doppler frequency shift,
- class of emission and type of modulation,
- total power flux density,
- power flux density in the reference bandwidth,
The station can also determine the orbital elements of space craft in order to identify unknown satellites e.g. in cases of interference.
Detection of up-link Interferers
Cases of up-link interference, i.e. not a satellite is the source of interference, but a satellite is the victim, appear more and more. Since users have obtained direct access to satellite capacities the number of earth stations has risen rapidly. Earth stations are the major source of up-link interference. It can be caused by both technical and operational faults. Illicit use of satellite transponders and cases of intentional interference to transponders have also been observed. Authorities, operators and users have to cope with this situation.
With the procurement of Antenna 4 Federal Network Agency is planning to introduce a new and advanced monitoring procedure for the detection of up-link interference. For the detection of uplink interference the detailed knowledge of the interfering signal is not necessary. The system locates interferers by processing the measured data of the time difference of arrival (TDOA) and of the frequency difference of arrival (FDOA) of the interfering signal at Leeheim via the interfered and via a neighbouring satellite. As soon as the location of the interferer is known, the interference can normally be swiftly eliminated.
The system covers the 1.5 - 1.8 GHz, 2.1 - 2.3 GHz, 3.2 - 4.2 GHz, 4.3 - 8.5 GHz and 10.7 - 12.75 GHz frequency bands. The 20 GHz range is currently under construction.
The space radio monitoring station´s central location within the European continent puts Leeheim in the proper position to offer its services also to other European countries.
Services to customers external to Federal Network Agency
The monitoring services as described can be provided to interested parties external to Federal Network Agency, subject to available capacity. Initial enquiries on more technical detail, availability and charges can be addressed directly to the space radio monitoring station at Leeheim under the following numbers: phone: +49 6158 940-0, fax: +49 6158 940-180 or Öffnet E-Mail-Feld
Correspondence can be forwarded by mail or by fax to the:
Federal Network Agency
for Electricity, Gas, Telecommunications,
Post and Railway
P.O. Box 80 01
Germany Telephone: +49 6131 18-0
Fax: +49 6131 18-5600