Iridium WOCE/SVP/BP

Buoy

METOCEAN WOCE/SVP/BP/Iridium

ByBernie Petolas, P. Eng.

Product ManagerMETOCEAN Data Systems Ltd.

Dartmouth NS B3B 1R9Canada

October 14, 2002 DBCP Technical Workshop 2002 Page 2

Introduction

• Product and Iridium Overview

• Block Diagram of Iridium Buoy

• Pros and cons of Iridium

• METOCEAN’s Iridium Communication

Infrastructure

• Deployment in Bering Sea

• Conclusions

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Product Overview

• Hourly data acquisition

• Barometer, SST and Submergence Sensors

• GPS positioning

• Bi-directional communications using the Iridium Satellite Network

• Customer Command/Data Interface (WWW) • Enhanced METOCEAN Digital Controller • Modular TMOS Software Architecture

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Overview of Iridium System

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Pros and Cons of Iridium

• Pros:• Bi-directional communications• Large data bandwidth• True Global Coverage (both time and space)• Potential data transmission costs saving• All digital connection

• Cons:• Size and weight of unit• Power budget versus telemetry costs• Data dissemination infrastructure• Unknown RF issues in high seas

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Block Diagram of WOCE/BP/Iridium Buoy

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System Components: Data MODEM

• Iridium 9500 Data Modem data rate is 2400 bits per second.

• Direct digital connection between buoy and METOCEAN via satellite network

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Digital Communications

• Direct connection via Internet to METOCEAN• An Web interface is always available to receive

messages and send commands• Buoy calls the Iridium ground station, negotiates

a PPP and connects to METOCEAN server • Programmable communication duration and

frequency

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METOCEAN’s Iridium Communication Infrastructure

• Based on METOCEAN iLink™ Server • Server monitors a port for incoming packets

from Iridium buoys• Accepts simultaneous connections from

multiple platforms• In effect, each buoy has a direct connection to

the database via the Internet

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Message Processing

• Each buoy maintains a queue of hourly reports, transmitted upon connection to the server

• An acknowledgement is sent back only if the data is successfully stored in the database

• Upon acknowledgement, the buoy deletes the message from its transmission queue

• If the message queue is full, the oldest message is deleted

• Programmable parameters allow flexibility in message throughput, data loss prevention and delivery costs

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Command Processing

• Provided by an outgoing message queue in the database

• User submits commands via web page• When connected, the buoy sends periodic command

request packets and an acknowledgement after a command is received and executed

• Commands are stored in the database• All buoy commands can be executed via the Iridium

interface• Very powerful but dangerous tool!

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Deployment in Bering Sea

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Conclusions

• Two-way communications and large bandwidth produce power savings

• Iridium message throughput is about 80%• Our database management system is

100%• Allows reconfiguration after deployment• Potential cost savings of 33% over other

satellite systems • METOCEAN can offer data services