More about SADIS

SADIS is a dedicated ICAO system, regulated and controlled under ICAO Standards and Recommended Practices and promulgated in ICAO Annex 3 - Meteorological Services for International Air Navigation and Annex 10 - Aeronautical Telecommunications.

It only carries ICAO-defined aviation products with the appropriate priority. SADIS 2G also forms part of the ICAO Aeronautical Fixed Service (AFS) to ensure that aviation data are distributed without conflict and in a timely way.

World Area Forecast System (WAFS) data

WAFS data, provided by WAFC London via terrestrial 64 kilo bit per second (kbps) lines, are uplinked from the hub at Whitehill to the INTELSAT 904 satellite located over the Indian Ocean at 60° E. Data are downlinked via a global beam to users in the AFI, EUR, MID and the western part of the ASIA region. The footprint stretches from eastern Atlantic, Cape Verde (20° W) to central Australia (140° E).

WAFS Internet File Service Data

Following the withdrawal of the USA Administered ISCS G2 service in July 2012, WAFS data is provided by WAFC Washington via their WAFS Internet File Service (WIFS) system. Access to SADIS or WIFS is determined by the appropriate Regional Air Navigation Plan. Further information regarding the use of WIFS as a backup to SADIS is available here: Obtaining a WIFS account as a backup arrangement for users of SADIS

Major systems and components

Hub

VSAT (Very Small Aperture Terminal) is the hardware component of the system, supplied by either iSat or Paradigm. This consists of: a 2.4-metre parabolic antenna ('dish') and mount; and a low-noise amplifier/down converter, usually called a 'low-noise block' (LNB).

Receiver (one-way)

A receiver/demultiplexer that must be sited indoors with connecting cables.

  • SADIS outputs use standard CCITT interfaces and protocols, and data are structured in accordance with WMO codes and formats
  • Separate permanent virtual circuits (PVCs) are allocated for the different types of data
  • Data will be output from a data port that complies with CCITT recommendations X.21 and V11
  • Data throughput speed of 64 kbps. Output data streams for SADIS 2G can be TCP, UDP or X.25.

PC/workstation

This hardware decodes, archives and displays data received from the SADIS VSAT (a list of known workstation manufacturers is held at WAFC London and can be supplied on request).

  • Designed to deliver the data to the end user in the 'open' industry standard X25 format TCP or UDP
  • Allows freedom to process these data in whatever manner is convenient to meet the user's requirement and/or communication system
  • May be linked into the output port of the VSAT

Site survey questionnaire

The SADIS site survey questionnaire asks the questions needed to help users install a SADIS receive-only terminal, choose a suitable location for the antenna and receiver unit, select the correct type of antenna mounting and consider how the terminal should be installed.

Site surveys are available from the two suppliers of SADIS 2G VSAT equipment - namely iSat (formerly L-Teq) and Paradigm Communications.

It is essential that a site survey is carried out prior to any other preparatory work, to ensure that the installation proceeds in a smooth and safe manner.

For further information, please contact SADIS 2G VSAT suppliers directly.

SADIS satellite finder

The SADIS satellite finder provides instructions to help users find the azimuth and elevation of INTELSAT 904, the satellite used for the transmission of SADIS data.

SADIS Satellite Finder View the satellite finder (PDF, 164 kB)

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Last updated: 3 December 2013