Iridium WOCE/SVP/BP Buoy METOCEAN WOCE/SVP/BP/Iridium By Bernie Petolas, P. Eng. Product Manager METOCEAN Data Systems Ltd. Dartmouth NS B3B 1R9 Canada

October 14, 2002DBCP Technical Workshop 2002Page 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

October 14, 2002DBCP Technical Workshop 2002Page 3 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

October 14, 2002DBCP Technical Workshop 2002Page 4 Overview of Iridium System

October 14, 2002DBCP Technical Workshop 2002Page 5 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

October 14, 2002DBCP Technical Workshop 2002Page 6 Block Diagram of WOCE/BP/Iridium Buoy

October 14, 2002DBCP Technical Workshop 2002Page 7 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

October 14, 2002DBCP Technical Workshop 2002Page 8 Analogue Communications Buoy must have scheduled turn-on time User must have a synchronized clock User dials buoy’s number (high cost and communication problems). Limited chances per day. May lose connection, get data corruption If buoy dials out, then need a bank of MODEMs and large infrastructure (like an ISP)

October 14, 2002DBCP Technical Workshop 2002Page 9 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

October 14, 2002DBCP Technical Workshop 2002Page 10 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

October 14, 2002DBCP Technical Workshop 2002Page 11 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

October 14, 2002DBCP Technical Workshop 2002Page 12 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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October 14, 2002DBCP Technical Workshop 2002Page 19 Deployment in Bering Sea

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October 14, 2002DBCP Technical Workshop 2002Page 21 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