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Last Update: 05 Apr 2007
User terminals

Easy Line-Up (ELU)


   

Objectives

Currently the process of setting-up and configuring a satellite terminal is very time consuming and requires the remote support of operators from the central station. Recently, Siemens Austria developed a concept called "Easy Line-Up" to support earth station antenna alignment for two-way satellite communication systems in an automatic way.

Features

Easy Line-Up is a method and system for supporting earth station antenna alignment for low-cost two-way satellite communication terminals. It guides the operator through the initial line-up and configuration procedure and subsequently provides continuous monitoring of the antenna alignment.

It covers the following relevant tasks:
  • Terminal Identification and configuration,
  • Antenna Alignment / cross polar check,
  • EIRP Adjustment (closed loop),
  • Configuration of GPS Coordinates,
  • Central web based system management.

Project Plan

For each phase of the development process a review is defined in order to verify the results of the phase concerning technical aspects, quality assurance aspects and project control aspects. The following shows an overview of the review meetings and review dates as actually planned for this project:

Review Description Due Date Location
KO Kick-off ESA 13 Jun 05 Siemens
BDR Baseline Design Review 15 Sept 05 Siemens
MTR Mid Term Review 15 Sept 05 Siemens
FR Final Review Jan 07 Siemens

Challenges

The system is developed in a way that it can be used in any bi-directional satellite communication environment.

SIECAMS Easy Line-Up is a method, which simplifies the initial line-up process in order to support clients and local distributors during the antenna alignment and configuration phase of earth station terminals, which provide two-way communication via satellite.

In order to establish and maintain reliable and high quality two-way communication services via satellite and in order to avoid interference to an existing service caused by unauthorized and/or out-of-tolerance transmission, operators are requested to perform a pre-transmission line-up when accessing a satellite for the first time.

For this purpose, the initial line-up phase focuses on EIRP, frequency and antenna alignment (azimuth, elevation, polarization), in order to ensure correct and interference free access to the satellite.

Thus an antenna must both be pointed correctly at the source of reception/transmission and, in the case of linear polarization; it must also be oriented about its axis to maximize reception of the linearly polarized signal. For this purpose, an antenna for linear polarized signals must be set up with particular care. In particular, if the setup is defective, the antenna transmits both with the required polarization and with the perpendicular polarization, which causes interference to other services. Consequently, standards generally require an earth station transmitting with linear polarization to satisfy a minimum polarization discrimination requirement.

The intention is to simplify the line-up process in order to enable local distributors or even clients to get the satellite terminal operational by themselves (self install).

In the following description, the expression 'return-link' refers to the signal transmitted from the earth station terminal via the satellite to the central site, such as the hub; and the expression 'forward-link' is used for the signals transmitted by the hub via the satellite to the earth station terminals.

The main goal of the SIECAMS Easy Line-Up is to support the client during the installation phase without the need to modify the earth station terminal in terms of installing additional measurement equipment and/or alignment mechanism.

For realizing this, a central site, such as the hub site monitoring station, needs to be installed in order to detect and identify line-up requests and to monitor the co-polar and cross-polar components (isolation measurement) of the signal transmitted from the earth station. The picture below shows this central site called antenna misalignment monitoring station.

In addition, the customer needs to run the dedicated SW application 'ELU-Client' on a PC / Notebook, which communicates with the In-Door-Unit (IDU) and guides the client through the installation, configuration and line-up process. The relevant communication link for terminal authentication from the terminal to the Antenna Misalignment Monitoring Station via the return link is performed via CW on-off keying initiated by the SW application. This capability will offer to transmit relevant information (terminal ID, MAC address, terminal capability, relevant subscriber data, etc.) as required during the individual tasks.

The communication in the other direction (from the antenna misalignment monitoring station to the terminal) is performed via the forward link, as soon as the FW link is successfully received by the earth station. The picture below shows a functional block diagram of the satellite interactive network including the antenna misalignment monitoring station, which communicates with the Line-Up SW application via the forward link. The dedicated SW application running on hub site ELU monitoring station is called 'ELU-Server'.


 click for larger image

Benefits

Web based system management
The ELU web-based system management tool, called ELU Earth, provides to the operator extended report functionalities including geographical map display, detailed reports from line-up measurement results, status overview of line-up stations, etc. ELU Earth is accessible via standard web browser and provides information of all line-up data, like GPS coordinates, line-up status, measurement results, time stamps, configuration files, log files, etc in a user friendly GUI.

Furthermore it provides centralized configuration of the ELU system as well as the satellite terminals. This can be seen as a first step towards an overall network management system for satellite networks.

The following shows a screenshot of the ELU Earth main window:


 click for larger image

The main benefits are as follows:
  • Simplified line-up during installation, e.g. automatic terminal registration in a DVB-RCS or VSAT network,
  • No separate communication path required,
  • Reduced personal resources in the network control centre as well as on-site,
  • Supports several simultaneous line-ups 24/7,
  • Closed loop power control through continuous monitoring of RF transmitted power during line-up process,
  • Continuous monitoring of cross-polar Isolation and EIRP during operation.

Current Status (dated: 31 Jan 2007)

The Easy Line-Up product is ready for sale and the project is now finished. Further enhancements to build onto the development to support several satellites and Hubs are scheduled for the future.


Last Update: 05 Apr 2007
 
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