May 2004Iridium Users Workshop, Seattle National Data Buoy Center’s Experiences with Real-Time Data Retrieval from Remote Stations using Iridium; and Data Distribution: GTS and IOOS Presented by: Steve Collins

May 2004

GOES Alternative Development May ’02, Tasking for non-GOES communications system Iridium selected for best coverage September ’03, 2 week test on 3 meter discus buoy in Gulf of Mexico –98% throughput, compared to 81% for GOES December ’03, certified for operational use –ARES payloads only

Concept of Operations (CONOPS) One “passive” remote modem per station (buoy or C-MAN) One to several “active” base station modems PC software-controlled base stations (W2K, Visual C++) –Automated data retrieval calls managed by ‘Station Caller’ software –Manual diagnostics/data retrieval calls managed by ‘Station Keeper’ software Base stations interface remote stations to NDBC real-time system

CONOPS (continued) All calls originated by NDBC base stations Remote stations ‘listen’ for incoming calls on programmed schedule for power management Remote station modems controlled by ARES payload –Call answering service –Interface to payload data archive –Interface to payload test/diagnostics –Interface to payload configuration (enable/disable sensors; manage payload timing)

Remote Station Operation

Base Station Operation

Real-time System Interface

Base Station Issues Antenna cable length limited to less than 3 dB loss Satellite visibility Will require additional base stations or equipment for entire network (only 3 stations per channel with current design for 15 minute reports) Software allows default PIN only Clock must be in synch with remote stations (GPS)

Remote Station Issues Security –No security “firewall” on remote stations –Security limited to general public not knowing station phone number for incoming calls. –Cannot make outgoing calls

Data Issues A number of time of observation issues had to be overcome for 15 minute observations Corruption of some temperature data during GOES transmission overlap time (similar to what occurs now when directional waves data acquisition overlaps GOES transmission) Web modifications to display multiple observations per hour, need public comment period to make public Will require tight configuration control and communications to avoid duplicate reports

Anticipated Improvement Multi-channel IRIDIUM modems for base station –reduce equipment costs –fewer PCs and modems –will require modifications to Station Caller and Station Keeper software

Benefits - IRIDIUM vs GOES Increase in data availability over GOES (so far) Lower power requirement –Power available for more frequent observations –Potential reduction in power systems failures Potential for more data –Time slots limited by NDBC controlled constraints –Message length not a factor –Retrieve missed reports Remote two-way communications –Remote reconfiguration –More data in changing environment conditions –Remote diagnostics Potential cost savings in field service using remote ‘repair’ and diagnostics Shore-side event driven reporting possible

Remote Diagnostics Allows remote access to all payload test functions Remote soft reset of payload Remote access to system error info Parameter table downloads –Correct parameter errors remotely –Reconfigure payload

CONCERNS Telecommunications costs (compared to no usage costs for GOES) Unknown future pricing Base station requirements for comms with 150 remote stations Performance in severe environments and weather events Contingency Plan for Base Stations

PLANS Install on two new buoys, this summer –funded by USCG –Seaward end of Juan de Fuca Strait and north end of Puget Sound –Top of hour GOES transmissions, bottom of hour Iridium transmissions Install on DART buoys (PMEL development) Install on prototype USCG Automated Identification System (AIS) equipped buoy, late this year or early next year

Potential Plans Install on all moored buoys and most C- MAN platforms for USCG AIS comms Use for NDBC data comms?

Data Distribution: GTS and IOOS Dissemination of non-GOES data Regional Observatory (University) data Iridium data

NDBC is a data assembly center in the IOOS architecture, receiving data from regional observatories, performing automated quality control, and distributing the data via the GTS and the NDBC web site.

Regional Observatories Public ftp* * Via MODEM Kit - request from NDBC DODS NDBC DODS NDBC MODEM Kit (Meteorological and Oceanographic Data Exchange Module)

University Data Solution

Iridium data received at NDBC is packaged like GOES messages and ftp’d to the same system that puts University system observations on the GTS

IOOS Data Distribution Later this year, NDBC will implement an OPeNDAP server. Iridium collected data will be displayed, as well as university data

CONTACT Steve Collins