PAGE CONTENTS
Objectives
The purpose of this activity is to design, develop and test a new right-handed circularly polarized (RHCP) VHF antenna to be used on vessels supporting the satellite VHF Data Exchange System.
The objectives are:
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Improve the link quality and throughput of the VDES system and demonstrate this in a real operating environment. Part of this is to reduce multipath fading and to look for a design where the gain is high at low elevations.
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The antenna should benefit satellite VDES users globally. It should be suitable for vessels operating in the Artic regions, particularly beyond the geostationary satellite coverage area.
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The chosen antenna to be industrialised and ready for mass production.
Challenges
Some key challenges:
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Finding the right antenna candidate that fulfills all specs
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Around 100 antennas were considered and simulated
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Prototypes were made for the most promising ones
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Size and maximum dimensions
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Narrow band, challenging to match.
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Design accommodating pitch and roll.
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Fulfilling Iso Level Mask.
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Polarization performance:
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Cross polar discrimination.
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Specular multipath suppression.
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Low elevation performance and overall gain.
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Nordic climate, ice
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During the measurement campaign it was challenging to get representable data for the standard dipole antenna because of noisy environments, making comparisons with the QFH challenging.
System Architecture
The new antenna is one component of the VDES architecture. The VDES satellite transmits with RHCP. A standard dipole antenna with vertical polarization is used as the reference, and both antennas are extensively tested in a maritime environment.
VDES satellite-based network proposed used in this activity
Plan
The project has the following milestones:
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Milestone 1 (MS1): System Requirements Review (SRR). Review of technology survey and patent search/study. Review of consolidated requirements and review of simulations and chosen antenna candidates. Date for review 14.09.2022
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Milestone 2: Review of technology baseline and verification of detailed design. Planned for January 2023
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Milestone 3: Test Readiness review and verified deliverable items. Planned for August 2023
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Milestone 4: Final review. Planned for November 2023.
Current Status
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The activity kicked-off in May 2022 and achieved MS1 System requirements review (SRR) on 14.09.2022.
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Comrod created a prototype of the final antenna candidate in January 2023 and started preliminary testing at Tau.
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Antenna design finalized June 2023.
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Comrod Manufactured and tested five 0-series antennas for test campaign in August 2023.
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Test campaign started August 2023, with multiple test locations. Tau, Trondheim, Svalbard.
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Measurements for over 300 passes collected at the test locations from August 2023 – May 2024.
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Final review and final presentation completed in May 2024.
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Project closed September 2024.
