telemetry for a coastal ocean observing system preliminary results using the iridium system

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();

cbc@unc.edu

http://www.unc.edu/~cbcoasis

http://www.seacoos.org