January 17/18, 2001

Presentation Summaries

A LEOS-based Data Delivery and Platform Positioning System

Bob Heinmiller - Omnet, Inc.
Ngoc Hoang - NAL Research, Inc.

A variety of commercial low-Earth orbit (LEO) satellite communications systems are now, or soon will be, in operation. These system have characteristics -- two-way communications, real-time data transmissions, global coverage, reduced costs, low-power lightweight transmitters and receivers, and small omni-directional antennas -- that make them very attractive for transmitting data from oceanographic data platforms.

The authors plan to develop and deploy a system for the delivery of data and grographical position from remote ocean platforms. The system will work with several existing and planned Low Earth Orbiting Satellite (LEOS) systems. However, the initial focus will be on Iridium which is now expected to continue in operation. NAL Research Corporation will outline the on-going development of a data communications package for remote science platforms utilizing commercial LEO satellite transceivers. The package will include an RF module, a modem, a GPS, and a data interface. Omnet will describe their plans -- in collaboration with NAL Research -- to develop and deploy a complete data delivery system, including a data-ready remote communications package, Iridium air-time, a data download server, and an Internet portal. The NAL/Omnet package will also provide for multi-channel connections to multiply the effective bandwidth. It is expected that a single multiplexor will be able to set up four connections on one antenna, and multiplexors can be ganged.

Bob Heinmiller Omnet, Inc. R.Heinmiller@omnet.com 21 North Central 540-885-5800 Staunton, VA 24401

Potential Submarine Launcher Systems for ACOMMS Buoys

Nicholas Venier

Existing submarine launcher systems, especially the 3 inch internal countermeasure launcher (ICL) and the Trash Disposal Unit (TDU), have provided an effective means to launch various development/test vehicles from submarines. These launcher systems are potential candidates for launching future ACOMMS buoys or other devices as required by technology demonstration programs. This presentation will provide an overview of the operational and physical characteristics of various submarine launcher systems and will highlight some of the physical characteristics of Fleet vehicles that are typically launched from these systems and also several demonstration vehicles that have been recently successfully launched. Included will be the issues that need to be addressed and the modeling and simulation tools used to assess the launchability of new vehicles from existing laucnhers and design modifications to launcher systems. The steps required to obtain initial Navy system Temporary Alteration (TEMALT) approval for launching demonstation vehicles and devices from submarines will be briefly discussed along with a ROM cost and schedule estimate based on a recent demonstration program.

A GENERAL VIEW OF GATEWAY PLATFORMS

Daniel E. Frye

Gateway platforms provide connectivity between submerged sensors, vehicles, and perhaps divers to distant platforms (typically ships, submarines, laboratories or other Gateways). The goal of the Gateways is to provide seamless networking between underwater sensors and mobile data gatherers and remote operators. Gateways also provide navigation fixes and in some instances may provide power to AUVs via docking stations. Existing Gateway concepts include surface moorings, pop-up moorings, AUVs, gliders, and drifters and have been developed for several general applications including, but not limited to:

a) Sensor to home connectivity, where home means the location of the people using the sensor information.
b) AUV and glider to home connectivity and navigation.
c) AUV recharging via a docking station.
d) Submarine to home connectivity.

These Gateway concepts all contain common elements that provide the communication and navigation functions as well as the physical systems that allow the Gateway to operate in the ocean environment. The common Gateway elements are:

a) Acoustic communications and navigation
b) RF communications and navigation (GPS)
c) System control and data storage
d) Sensors
e) Power and power distribution
f) Mooring system or vehicular system
g) Deployment system
h) Docking system (if necessary)

The standards, requirements and specifications of each of these common elements need to be defined in order to develop Gateway concepts that allow optimal interoperability in a variety of applications. This presentation will introduce a preliminary set of standards and requirements for Gateway platforms that may stimulate discussion at the workshop.

NSW Embedded Littoral Sensor Network Michael Wood, WARCOM CDR

NSW niche is clandestinely embedding various maritime sensor arrays in the littoral environment for various National or Theater customers. Currently, potential sensors include: Advanced Deployable System (ADS): An acoustic array clandestinely embedded by clandestine means in the littoral, coast, harbor or choke point. This is not a NSW or MFP-11 program but a MFP-2 ONI program. Semi-Autonomous Hydro Reconnaissance Vehicle (SAHRV): A small preprogrammed UUV for conducting hydrographic reconnaissance, water sampling and other missions. This is a NSW program for VSW/MCM IOC is FEB 01 There is a SAHRV docking station developed by Woods Hole. Seal Weapons and Surveillance Platform (SEA WASP): A fiber optic linked, reconfigurable, sensor & explosive UUV controlled by an NSW operator. Currently, all these systems need to be either recovered or linked to land via fiber-optic cable in order to collect the desired information. The NSW data-buoy collector/transmitter would be linked to all these systems, were feasible, and collect the data via fiber-optic link and transmitted through a pop-up buoy to satellite, UHF or HF.

Overview of Acoustic Communications Lee E. Freitag

This presentation will consist of two parts, one, an introduction to acoustic communications; and two, a summary of issues associated with installation of acoustic communications systems in different Navy platforms. (1) Challenges in acoustic communication arise from ocean propagation, natural and man-made noise, source-receiver motion and system size, weight and cost constraints. Reducing the probability of detection creates additional problems which may impact system design. However, a number of different solutions do exist. These solutions include multi-rate phase-coherent modems as well as frequency-hopped FSK and multi-tone FSK. The selected solution depends upon link requirements and the conditions under which it will be used. (2) The acoustic communication module of the Universal Navigation and Communication Gateway provides the subsea interface to fixed instruments, UUVs and manned submarines. The design of the acomms module must therefore provide frequency, modulation and protocol compatibility with the modems installed in those devices. Unfortunately, the platforms have different capabilities and may operate in a number of frequency regimes. The modem module in the gateway must support the intended user(s) while minimizing the total number of designs and thus the overall cost.

Overview of RF Communications

Ken Gamache

This presentation will provide an overview of RF communications for oceanographic applications. It will discuss the type of telemetry options available to the user given the specific application, i.e., near shore, coastal, deep ocean, polar. It will describe the differences between Line-Of-Sight (LOS) and Beyond Line Of Sight (BLOS) telemetry and the limited number of BLOS options available. The focus of the presentation will shift to a discussion of these BLOS options. Existing and planned systems will be described. Advantages and disadvantages will be discussed. Finally, the presentation will conclude with a realistic and practical assessment of these BLOS systems for oceanographic applications.