General document | Maritime Laser Technology Communications Trial 98152-19703

ABSTRACT

This General Document describes the objectives, methodology, and results of Maritime Laser Communications Trial 98152-19703 held at Port Wakefield Proof & Experimental Establishment in September 2011. A novel analogue FM ship-to-shore communications system was used to demonstrate video and bidirectional audio transmission up to 3km.

EXECUTIVE SUMMARY

There is increasing interest in free space optical communications (FSOC) as an alternative to fibre optics and radio frequency communications, particularly for 'last mile' applications and applications with size, weight and power restrictions. The potential advantages of free space optical communications include high bandwidth, no spectrum licensing issues, smaller lighter payloads, low probability of intercept and immunity from interference / jamming.

Laser Technology

As part of Task 07/009 Communications Support to Capability Development, C3I Division is researching concepts and technologies that can be applied to laser communications in the maritime environment. Compared to operating over land, the maritime environment offers significant advantages in that it usually provides line-of-sight conditions, which is required for FSOC, and its atmospheric scintillation noise is typically one to two orders of magnitude lower.

This General Document describes the objectives, methodology, and results of Maritime Laser Communications Trial 98152-19703 held at Port Wakefield Proof & Experimental Establishment in September 2011. The primary objective of the trial was to demonstrate ship-to-shore optical communications, as an intermediate step to ship-to-ship communications. This work is underpinned by the modulating retroreflector (MRR), which allows high bandwidth optical communication using a laser technology system at only one end of the link. DSTO has a close collaboration with the US Naval Research Laboratories (NRL) in FSOC, and the optical link demonstrated in the trial used an MRR on loan from NRL, under the auspices of a TTCP (The Technical Cooperation Program) equipment and material transfer.

During this trial an eye-safe, free space optical ship-to-shore communications link was successfully demonstrated. In particular, a novel FM audio/video communication system successfully operated at a transmission distance of 3 km. This is, to our knowledge, the first demonstration of a bidirectional audio/video link using modulating retro-reflectors.

These measurements indicate that this FSOC system is a feasible technology for the Royal Australian Navy. It has the potential to provide additional capabilities, such as: communication during EMCON conditions; provision of a redundant communications channel; and bandwidth intensive network centric operations. Further, the laser technology demonstrated in this trial can be readily extended to ship-to-ship communications.