telemetry for a coastal ocean observing system preliminary results using the iridium system chris...
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Telemetry for a Coastal Ocean Observing System
Preliminary Results using the Iridium System
Chris Calloway, Sara Haines, Collin McKinney, Luke Stearns, Harvey Seim
SEACOOS / NCCOOS / UNC-CH Dept. of Marine Science
http://www.seacoos.org
Southeast Atlantic Coastal Ocean Observing System (SEACOOS)
A System of Subregional Systems
Five Iridium efforts:
UNC: NCCOOS towers
UNC: Slocum Glider
USC: Caro-COOPS buoys
GA Tech: TriAXYS buoys
Univ. Miami: SWAMP profiler
Towers Buoys
Remote(Shore Radar& Estuaries)
Iridium-enabled Near Real Time Observations
SlocumGliders
NCCOOSInitial Deployment(in SABSOON waters)
Navy TACTS towers
(Tactical AircrewCombat TrainingSystem Range)
Move to Oceana Range
Tower Instrumentation
AtmosphericTemperature, Pressure,Humidity, Rainfall, Infrared,Visible spectrum, Wind speed,Wind direction, other….
In-water/Near-surfaceWave pressure, Tidal height,Wave height, Wave period,Conductivity, Temperature,Pressure, Salinity, Density, other…
In-water/Near-bottomCurrent Profile, Current Speed,Current Direction, Conductivity,Temperature, Pressure, Salinity,Density, other…
Current technology (Caro-COOPS buoys)
ISU to ISUDedicated data logger (ZModem)Offshore in periodic autoanswerShore dials in to observing platform
Low throughput (100 bytes/sec)Instrument limitations (serial/analog IO)Limited development environment68332 CPU256K RAM / 256K Flash
Low power (150 mA)-40°C to +85°C
95% relative humidity
Developing technology (NCCOOS towers)
ISU to ISPSBC with instrumentation bussISU “calls home”Connect to generic repository
High throughputFlexible instrumentationVisual development environmenti486 CPU16MB RAM / 12MB Flash / 512MB PCMCIA
Low power (330ma)-10°C to +55°C
NCCOOS component of SEACOOS
Volumetrics: 2MB/day
Link: PPP
Transport: FTP
Iridium Pioneers
Iridium 9500
Rated 2.4 kbits/sec
-30°C to 60°C
85% relative humidity
~1A @ 4.4VDC average
Start
Data Acquisition Data Transfer
CommLib
Win CE RAS
CommLib
Microsoft Embedded VC++
Callable from Visual Basic
Chunked FTP transfer(InternetWriteFile)
Logs errors and statistics
APIDllMainSendFilepollFinishedpollSuccessful
Error recovery strategy
1) Dial error: hang up and retry if off hook and not connected; else disconnect and retry.
2) Dial timeout: hang up and retry if off hook and not connected; else disconnect and retry.
3) Dial retry limit reached: Reboot modem.
4) Disconnect error/timeout: Reboot modem.
5) Hangup error/timeout: Reboot modem.
6) No IP: disconnect and redial.
7) No IP retry limit reached: Reboot modem.
8) No TCP connectivity: disconnect and redial.
9) No TCP connectivity retry limit reached: Reboot modem.
10) FTP error: retry FTP if nonfatal, else disconnect and redial.
11) FTP timeout/retry limit reached: disconnect and redial.
12) Modem reboot limit reached: turn off modem and wait awhile.
Metrics
Median burst rate: 7503 bytes/sec
Average power consumption: 1 watt
median
75 quartile
25 quartile
Transfer Rates
Transfer Rate Statistics (bytes per second)
Points: 460Average: 6563Median: 750325 Percentile: 441775 Percentile: 8334Std Dev: 3047Minimum: 200Maximum: 13582
To Do:
GPLMore statistics (Connect rate, connect time)New APIProtocol logging9505 modemIridium Data GatewayISAPILinux
COMMLIB_API BOOL sendFile(TCHAR* localFilePath, TCHAR* localFileName, TCHAR* remoteFileName);
COMMLIB_API BOOL pollFinished(TCHAR* localFilePath, TCHAR* localFileName);
COMMLIB_API BOOL pollSuccessful(TCHAR* localFilePath, TCHAR* localFileName);
COMMLIB_API BOOL retractFile(TCHAR* localFilePath, TCHAR* localFileName);
COMMLIB_API INT locateFile(TCHAR* localFilePath, TCHAR* localFileName);
COMMLIB_API INT queueDepth();
COMMLIB_API BOOL relocateFile(TCHAR* localFilePath, TCHAR* localFileName, int newOrdinal);
COMMLIB_API TCHAR* queryFile(int ordinal);
COMMLIB_API BOOL clearQueue();
COMMLIB_API BOOL shutDownComm();
COMMLIB_API BOOL restartComm();
COMMLIB_API BOOL isCommActive();
