European Space Agency

ViaLite Air

Objectives

The project has three main objectives. These are research, development and integration/test of the novel fibre optic links.

  • Research – this objective is to breakdown user level requirements into lower level system level requirements followed by evaluating potential system architectures prior to the main body of the product development commencing. This objective will be dominated by optical and microwave research.
  • Development - using the knowledge gained from the research phase with the objective of realising a marketable product. Development of microwave circuit PCBs, the mechanical housings and system software will be developed into a complete product solution to meet the market need. This objective will be dominated by optical, microwave, mechanical and software engineering.
  • System integration and test – this objective is to bring the electro-optic, mechanical, and software elements of the project together and test the system for inter-working issues. Hardware and software bugs will be identified and rectified ahead of final production standard articles being submitted for regulatory approval.

Challenges

Many challenges need to be overcome to develop truly novel fibre optic links for high frequency RF signals. The optical components will be the largest individual components in the system, and are a relatively fragile sub-system. Either developing new optical components or engineering novel solutions based on exiting components will be the main challenge. Achieving an acceptable product size and cost will also be challenging.

Benefits

By converting the high frequency RF signal to analogue optical signal at the power amplifier / low noise amplifier interface close to the antenna feed, losses are minimised and the signals from multiple antennas can be brought via fibre to a central site with a central set of frequency converters. These can service multiple heads on a 1-for-n redundant basis.

The specific product benefits are reduced equipment size; capital cost savings and bringing a large element of the RF chain into a benign environment, increasing equipment longevity, performance, and providing ease of access for maintenance. For diverse sites which are quite often not managed by the customer there are further benefits because fewer assets are located at remote sites as all conversion can be done pre fibre leaving the main site under their control.

Features

To keep signal losses to an absolute minimum, the system chassis needs to be a relatively small form-factor. A 1U chassis form will be used to house the links, minimising the distance between frequency converter outputs and the electro-optic converters. 

In addition to the chassis, mechanical housings will be developed to mount the electro-optic converters to the feed horn equipment. The waveguide connections of the LNA and HPA at the dish end of the link will be connected to directly, again minimising the distance the signal travels in an electrical format. A key benefit for this new product is reducing the need for large equipment racks at the dish end, so these outdoor housing will be compact, light, and rated to operate in harsh environments.

The new product will contain advanced user interface features in software and firmware and support new configuration settings when required, for example if updates are required to the GUI, and SNMP) interface.

System Architecture

The system will consist of outdoor equipment mounted at the antenna site, and indoor equipment fitted in an equipment room; the intra-facility link will be made by a run of fibre.

The antenna end equipment will consist of an optical LNB for attachment to a feed horn for the downlink signal; the uplink signal will be packaged to interface to an HPA. Power will be fed to the outdoor elements from a localised DC source.

The connection between outdoor and indoor equipment will be made by a run of dark fibre optic cable. This element of the system is typically installation specific, so the system allows for the connection to be made over individual dedicated fibre strands, or for it to be multiplexed onto a single fibre, depending on the operator’s requirement regarding cost and redundancy.

The indoor equipment will be modular by design to allow the conversion back to an electrical signal to occur as close to the down-convertor as possible, minimising extraneous loss and signal distortion. This will initially be a 1U 19” rack configuration, but will be expandable to a larger configuration as required.

Plan

The project has been broken down in to multiple work packages. The top level work packages are project management, research, hardware development, business case development, software development, integration and test.

Current status

The initiation phase of the project has been completed and the microwave and optical investigation phase is now coming to a close. The next stage of the project is the design phase where the selected architecture will be designed into a prototype product to enable system test.

Status date

Wednesday, March 27, 2019 - 11:26