BODENSTATIONEN

FRAGEN & ANTWORTEN (Englisch)

• EUTELSAT GROUND SEGMENT
  • What are the compulsory steps to perform in order for an earth station to access the Eutelsat space segment?

    • Once the space capacity has been reserved, the technical data of the earth station must be submitted for approval to access the Eutelsat space segment. The application is processed on-line, and once the technical data has been verified and the earth station approved, an official approval letter will be sent by e-mail confirming the assigned earth station code and the access conditions. In some cases the earth station may be subject to tests to confirm the performance of the antenna and associated ground equipment.

      Before accessing the Eutelsat space segment, it is imperative that the Eutelsat CSC is called in order to carry out a verification test before the transmission takes place.

      The above steps are necessary for all types of antennas, including the Eutelsat type approved.

      For SNG access, see also the document SNG carriers Universal Access Procedures (PDF, 114 KB)

  • What type of technical data must be submitted to approve an earth station to access the Eutelsat space segment?

    • The following data is required to submit an earth station for approval:

      General: Earth station name, type of station, planned type of service

      Fixed earth station location: Nearest town, country, latitude, longitude, address, telephone, facsimile, e-mail

      Service: Type of service, planned start date

      Antenna: the information required depends on the type of antenna chosen:

      • Type approved or individually approved antenna: Only tracking information and G/T are required
      • Antenna (Other): Manufacturer of main reflector, model, type of antenna, manufacturer of feed, number of feed ports, type of receiver, polarisation, tracking, Tx and Rx gains, G/T
      • Transmit equipment: Type, rating, maximum EIRP capability, overall RMS EIRP stability, Tx frequency stability, Number of Up converters, Number of Down converters
  • Why do earth stations need to be attributed a Eutelsat earth station code prior to accessing the Eutelsat space segment?

    • The Eutelsat earth station code identifies univocally the earth station and in particular, allows the control and monitoring of its access to the Eutelsat space segment.

      The code is composed of two or three fields separated by a hyphen:
      Country code (maximum three letters, e.g. F for France, ITA for Italy, etc.)
      Town or site code (maximum three letters e.g. PAR for Paris)
      Progressive three digit code.
      For example: F-PAR-001

      For transportable earth stations, only the first and third field are normally present: for example: F-99

      For VSATs, the second field is replaced by a three-letter code with the abbreviation of the VSAT network name; the third field contains four digits and is followed by the letter V. For example: F-ABC-0001V

  • Why and how should VSAT operators provide Eutelsat with regular updates of the locations of their terminals?

    • See Infonote 5: VSAT terminal registration (PDF - 30 KB)

  • What is a UPPC?

    • See Infonote 9: Use of UPPC (Up-Link Power Control Units) (PDF, 72 KB)

• EUTELSAT SPACE SEGMENT
  • How do you calculate polarisation azimuth and elevation of the Eutelsat satellites?

    • The linear polarisation planes (defined as X and Y and orthogonal to each other) of most of the Eutelsat satellites are not parallel/orthogonal to the equatorial plane. For historical reasons, the polarisation planes are inclined by an angle with respect to the equatorial plane. This angle is referenced as the polarisation skew.

      This value is of fundamental importance for the following types of antenna, whenever the polarisation alignment is performed in open loop:

      • Earth Stations on Vessels (ESVs)

      • Satcom-On-The-Move (SOTM)

      • Auto-pointing antenna

      If the pointing and polarisation alignment software of these types of antenna did not take into account the skew value, the polarisation discrimination achieved at the end of the alignment would suffer a major degradation with respect to the value which the antenna optics could theoretically yield. As a consequence, there would be a high risk of interference to other services on the opposite polarisation and the achievable performance would not be met.

      The reference X-polarisation is defined as the polarisation where the plane makes an angle of 93.535° in an anti-clockwise direction, looking towards the earth, about a reference vector with respect to a plane containing this vector and the pitch axis. The reference vector is defined as the vector from the satellite in the direction 0.21° towards west and 6.07° towards north in satellite coordinates.

      The reference Y-polarisation is defined as the polarisation where the plane is orthogonal to the X-polarisation plane and the reference vector defined above.

      In other words, the Eutelsat satellite skew is +3.535°, clockwise when looking at the satellite from the earth, from anywhere on the meridian (in the northern hemisphere) corresponding to the orbital location of the satellite.

      In the southern hemisphere the skew is +183.535°, clockwise, from anywhere on the meridian corresponding to the orbital location of the satellite.

      There are several satellites in the Eutelsat fleet using linear polarisation which are an exception.

      See the attached document on Calculation of azimuth, elevation and Polarization for non-horizontal aligned Antennas (PDF, 14 MB)

• ESVAs
  • What is an ESVA?

    • An ESVA is necessary in order to verify the antenna performance, i.e. the off-axis radiation, the cross-polar discrimination Transmit and Receive gain, G/T, maximum EIRP capability.
      
      It is mandatory for antennae with a large dish size.
      
      Minimum requirements for the correct performance of the ESVA are that the antenna should be motorised in Azimuth and Elevation. Nevertheless, ESVA tests can be performed on any type of earth station. In the case of non-motorised antennae, necessary arrangements can be made to enable the angular read-out of the antenna.
      
      Once the performance has been verified and considered acceptable, a certificate of earth station performance granting indefinite and unconditioned access will be delivered to the earth station owner.
      
      If the performance is not acceptable, either the test must be repeated after the necessary adjustments have been made to the antenna, or some limitations will be enforced (typically on the maximum allowed transmit EIRP and also on the duration of the approval).
      
      To find out more, or to arrange for an ESVA test, please contact the Earth Station Approval Office:
      +33 1 53 98 38 63 / 46 13 or esapproval@eutelsat.com.

  • Why are ESVA tests necessary?

    • ESVA tests are a very cost-efficient means to test an earth station and ensure that the antenna manufacturer specifications are being met.

      By checking the off-axis radiation, Eutelsat ensures that the earth station antenna, when transmitting, will not interfere with other carriers transmitted on satellites adjacent to the satellite being accessed.

      By checking the cross-polar performance, Eutelsat ensures that the earth station antenna will not interfere with other services carried on a transponder cross-polar to the one being accessed by the earth station.

      Moreover, the transmit antenna gain and G/T can be precisely measured. The ESVA test enables the earth station operator to calibrate the transmit and receive chains and to determine the exact earth station transmit EIRP as well as the maximum earth station EIRP capability. With the assistance of the Eutelsat Reference Station, the Station Under Test can be properly aligned and therefore prepared for the operational traffic.

  • What's the cost of an ESVA test?

    • For information on the cost of an ESVA, please contact the Earth Station Approval Office: +33 1 53 98 38 63 / 46 13 or Esapproval@eutelsat.com

  • What are the Universal Access Procedures?

    • Please see the Universal Access Procedures ITU-R SNG.1710.

  • What is the background of Azimuth Correction in conjunction with antenna pattern measurements?

    • Please download the documentation: "Azimuth Correction for Elevation-over-Azimuth Positioners"

• MAXIMUM ALLOWED EIRP
  • How do I calculate the maximum allowed EIRP0 density for Ku-band Transmissions?

    • See the document Maximum Allowed EIRP Density for Ku-Band Transmissions (PDF, 71 KB)

  • How do I calculate the maximum allowed EIRP0 density for C-band Transmissions?

    • See the document Maximum Allowed EIRP Density for C-band Transmissions (PDF, 68 KB)

  • What’s the EIRP0 density?

    • Approval to access the Eutelsat space segment stipulates the maximum allowable EIRP density at beam edge (i.e. at the satellite receive contour of 0 dB/K). This specific EIRP density is also known as EIRP0 density. The EIRP0 density can be either referred to 4 KHz or 40 KHz band, its measurement unit is expressed in dBW/4 KHz or in dBW/40 KHz.

  • How is the maximum allowable transmit EIRP density calculated, knowing the maximum allowable EIRP0 density at beam edge and the site location?

    • To find out the maximum allowable EIRP from the site where the earth station is located, the calculation is as follows:

      Max EIRP density=EIRP0 density - Satellite G/T towards the TX earth station.

      The EIRP density can be either referred to 4 KHz or 40 KHz band, its measurement unit is expressed in dBW/4 KHz or in dBW/40 KHz.

  • How is the maximum allowed EIRP calculated, given the maximum allowed EIRP density?

    • Given a Transmit Symbol Rate(TSR) of X (expressed in KBaud) and a Maximum allowed EIRP density (expressed in either dBW/4 KHz or dBW/40 KHz):

      Max allowed EIRP for a signal transmitted with a TSR of X Kbaud = Maximum allowed EIRP density (referred to 4 KHz band)+10*log (X/4)
      
      Or,
      
      Max allowed EIRP for a signal transmitted with a TSR of X Kbaud = Maximum allowed EIRP density (referred to 40 KHz band)+10*log (X/40)
      
      In both cases above the measurement unit of the EIRP is expressed in dBW.

• TYPE APPROVAL & CHARACTERIZATION
  • What is the difference between type approval and characterization?

    • Type Approval is a process of quality monitoring for large production series of antennas and VSATs. The tests are performed initially on 3 samples randomly selected from the production series and are submitted to the tests described in ESOG 120. Periodically, in time, the quality is checked by repeating a subset of the tests on other production samples.

      Characterization is an antenna validation process applied to small production series up to a few dozen units. The tests performed are the same as for Type Approval but they are done on a single sample.

      ESVA is a validation process for a single antenna. It follows the ESOG 130 procedures and is reserved for antennas that can't be tested in ranges (generally due to their size).

  • What are the typical requirements for type approving a VSAT radio unit?

    • Please refer to ESOG 160 (PDF, 278 KB).

  • Can "Non-Type approved antennas" access the Eutelsat space segment?

    • Yes, access to the Eutelsat space segment is not restricted to type approved antennas only.

      There are three types of antenna:

      • Type Approved/ Characterized, which have undergone a long process of verification and testing, often witnessed by Eutelsat and/or other satcom operators. Individual verification is not required for this type of antennae.
      • Individually Approved, which are not type approved but whose performance is known to Eutelsat and for which individual verification is not strictly mandatory. Eutelsat, however, reserves the right to instigate the performance of verification tests at any time should problems occur.
      • Other antennas not falling into any of the categories above and for which individual verification of the performance is required.
  • Can “Non-Type-Approved VSATs” access the Eutelsat space segment?

    • Yes. However, as VSAT networks often comprise hundreds or even thousands of VSATs, when rolling out a large VSAT network on Eutelsat space segment, VSAT type approval is strongly recommended, in order to pro-actively avoid interference to other services.

  • What's the difference between a type approved/characterized antenna and type approved/characterized VSAT?

    • Type approval for an antenna (coded EA-Axxx) concerns the antenna inclusive of all the passive radio components and its radio-electric performance.

      Type approval/Characterization for a VSAT (coded EA-Vxxx) concerns the antenna (and its associated radio-electric performance) equipped with the active radio components, i.e. the transmit (HPA) and receive (LNA/LNB) used with that antenna. Typically the VSAT is approved for a specific network or base-band technology.

  • What's the cost of a type approval?

    • Eutelsat does not charge any fees for this kind of activities. The applicant shall take charge of the cost of the third parties laboratory chosen for the tests and associated logistics.

      Also, tests performed in Eutelsat premises at the Rambouillet Teleport are not charged. Nevertheless, if the tests impose the Eutelsat staff to travel, the associated expenses are billed to the applicant.

• CARRIER ID
  • How can I provide Carrier ID to identify sources of satellite RF interference?

    • See the attached document (PDF 40KB).