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 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 the central Australia (140° E).

International Satellite Communication System (ISCS)

This complimentary service, provided by WAFC Washington, uses satellites that cover the remainder of the globe to complete the ICAO AFS satellite broadcast global coverage. There are two ISCS satellite broadcasts, one covering the Atlantic, and one covering the Pacific. These overlap with SADIS to ensure worldwide availability of WAFS information and OPMET messages.

More about ISCS

Major systems and components

Hub - VSAT (Very Small Aperture Terminal) is the hardware component of the system, supplied by either L-Teq 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. Note that the X.25 stream is backward compatible with SADIS 1G.

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 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 the SADIS 2G VSAT suppliers directly.

Download the L-Teq site survey questionnaire (coming soon)

Download the Paradigm site survey questionnaire
(PDF, 434 kb)

Requires Adobe Reader 7.0 or later

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.

View the satellite finder
(PDF, 1.0 Mb)

Requires Adobe Reader 7.0 or later