LOCOMO - LOw COst and compact Ka-band MObile satcom terminal

Objectives

The main objective of the project was to design, develop and test a low profile satcom-on-the-move (SOTM) ground terminal operating in Ka-band to enable broadband communications. Current main satellite operators have selected Ka-band for providing high capacities and broadband connectivity to users. The new service requirements and high capacity Ka-band satellites introduce new challenges to the VSAT ground segment equipment.

The need of communication on-the-move has being indentified for strategic applications; such as, emergency, governmental and security networks. Consequently, wide coverage and high availability are extremely important for these missions.

For this reason, the LOCOMO terminal was envisaged to cover the market opportunities of high priority networks with a low cost, low profile and compact terminal where on-the-move capability provides broadband communications anywhere and anytime, even in transit, and facilitates the missions of these forces.

Challenges

The principal challenge of the project was to design, develop and test a LOCOMO terminal able to provide the advantages of using Ka-band technology by maintaining a low cost and low profile (compact size) satcom-on-the-move.

The proposed antenna solution based on slotted waveguide technology made possible to deal with compact size and dual switchable polarization requirement. However, antenna design complexity was increased.

The necessity of using new GaN-based amplifiers for Ka-band to improve efficiency and reduce losses made the design of SSPA a challenge.

On the other hand, the usage of cost effective sensors to provide a high feature become an important demand to be considered during the design stages.

Benefits

The LOCOMO terminal offers a solution to provide broadband satellite communication on-the-move to strategic services, like emergency, governmental and security applications.

The proposed solution features low profile characteristic, since planar technology antennas enable compact integration with the RF frontend.

The traditional solutions based on parabolic antennas may found out a competitor in LOCOMO terminal, whose performance is leading high performance and, additionally, cost is lower existing solutions.

Features

The LOCOMO terminal was intended to provide broadband communication for emergency, governmental and security networks. It is characterised by the following system and terminal features:

  • High availability and wide coverage of satellite
  • High reliability connections, > 99.5%
  • Fast deployment
  • Network based on more than 100 remote terminals, considering man-portable and on mobile ground vehicles
  • Broadband communications, > 3Mbps
  • On-the-move operation
  • Dual switchable polarized antenna: LHCP, RHCP
  • Ka-band: TX 29.5-31.0 GHz; RX 19.7-21.2 GHz
  • Ka-band regulatory, ETSI EN 303 978
  • Low profile and compact size
  • Low cost

The next demonstrator has been completed in the project.

System Architecture

The general architecture contemplates a solution that evolves the traditional on-the-move terminals (parabolic antenna based) with the usage of planar antenna technology to reduce profile.

The following characteristics are key for the proposed approach:

  • Planar antenna based on slotted waveguide technology
  • Isolated TX and RX apertures, in front and rear side of the antenna panel
  • Circular polarization (RHCP in TX and LHCP in RX at front panel and vice versa at rear panel)
  • Dedicated SSPA per each TX polarization, increasing EIRP and reducing consumption
  • Dedicated LNA per each RX polarization, improving G/T
  • Mechanically steered in two axes, azimuth and elevation
  • Embedded PAT subsystem
  • GaN-based amplifier in SSPA

The LOCOMO terminal is consisting in two main blocks: the outdoor unit (ODU) that is implementing the Antenna, RF transceiver and PAT&Mechanics subsystems; And, the indoor unit (IDU) that is comprised by an RF module, the modem and power supply unit.

Plan

LOCOMO project has been divided in several activities, called work packages:

  • WP0000 – Project Management
  • WP1000 – System Definition. Focused on the system analysis, the definition of global terminal specifications and overall architecture. Subsystem level definition and test plan are also approached.
  • WP2000 – System Development. Design manufacturing and test at subsystem level are carried out. Global terminal integration and subsystem interfaces are also completed.
  • WP3000 – System Integration, Test and Validation at global terminal.

Current status

The project has covered the design, develop and test phases of a satcom-on-the-move terminal operating at Ka-band. A complete prototype was developed to assess the proposed solutions and the performance at subsystems and global terminal levels. Within the antenna subsystem, based on slotted waveguide technology, it has been validated not only the design tools but also the manufacturing processes. Some points of improvements have been identified, however an important progress towards a product was achieved. The project has been completed.

Contacts

ESA Contacts

Status date

Tuesday, October 9, 2018 - 07:53