|Satellite Coordination Calculation & Software (http://www.satcom.co.uk/article.asp?article=19)|
|The pages which follow are the slides of a lecture presented
by Mark C J Posen of RPC Telecommunications Ltd.
The slides were created using Microsoft PowerPoint and converted to HTML. During conversion the slides were combined into 7 sections.
You can navigate between these sections at will from the left hand side. However, bear in mind that for the slides to make the most sense, it is suggested that you read through them in order.
Please note that this presentation contains the lecturers notes, and so in some places
are not complete. If you have any questions regarding these lectures please contact the
|What do we need to be able to do for successful
Link and interference analysis:
Data gathering and processing:
|Software tools can assist with all these tasks:
Software is available from a number of sources, but the main "software" needed to do successful coordination is in your own brain!
So we will look at some manual analysis before we review software tools.
|Link & Interference Analysis|
|Link budget refresher:
Carrier to Interference refresher:
Normally simplify by assuming that Lp = Lp.
Define receive antenna discrimination, Dr = Gr (φ) - Gr (φ), typically 3 or 4 dB for a satellite receive antenna, generally much higher, say +20 to +40 dB for an earth station receive antenna.
So simplify terms:
This is a very simple equation; satellite to satellite coordination is not technically difficult to analyse!
Some additional complications to bear in mind:
|Protection Ratio Analysis|
|Protection ratio is the minimum acceptable single entry C/I
for a wanted carrier.
This is defined by ITU-R Recommendations. Recommendation ITU-R S.741 summarises the protection ratios for different wanted carrier types. Protection ratios are generally defined in terms of an "allowable" interference level as a proportion of the thermal noise in a link.
Examples for different wanted carrier types:
FDM/FM (multiplexed telephony) carrier
|Databases, Data Gathering & Processing|
|Coordination analysis needs information on
"wanted" and "interfering" satellite networks.
Some regulatory information:
Detailed technical information:
The ITU maintains a comprehensive database of all networks (satellite and terrestrial) undergoing coordination and those that have completed coordination and are recorded as in use (Master International Frequency Register - MIFR).
This database should be the source of all regulatory and technical data used for coordination. Most software tools use this database.
|ITU Software Tools|
|The ITU is responsible for the publication and registration
of satellite networks filed by administrations.
To support this work the ITU produces a number of software tools available for download and/or purchase via the ITUs web site (see here).
Some of these are available to public users, others need ITU "TIES" password (limited).
|ITU Space Radiocommunications Stations Database (SRS)|
|This database is a subset of the MIFR dealing with all space
It is available online via the SNS online system, updated daily. It is also available on CD-ROM - SRS CD-ROM, published every six months. Also a weekly CD-ROM of new networks added to the database, called the International Frequency Information Circular (IFIC) is available.
|ITU SNS Online|
|Access to the online data can be found here.
It gives access to:
|SpaceQuery software offers similar functionality to the SNS Online system. It is a CD-ROM based database tool. It allows a user to query and extract information from the SRS database.|
|GIMS - "Graphical Information Management System".
This software allows access to and viewing of (as well as creation of new) satellite beam footprint diagrams. It can be used linked with SpaceQuery or in a stand-alone mode.
The API is published so can be integrated with your own software.
|Other ITU Tools|
|ITU has a number of other tools:
Data management tools:
Data analysis tools:
|Proprietary Software Tools|
|A number of commercially available software tools are available to undertake various tasks:|
|RPC Software Tools|
C/I Analysis Tool
|Calculating C/N and C/I quickly and accurately is a key
requirement of successful coordination.
There are several software tools exist to assist in this but the ability to make quick manual calculations is a useful skill.
Also accurate data gathering and processing, using ITU software and other tools can ensure a successful coordination result.
Copyright 2002 Satcom Online (http://www.satcom.co.uk)