Portable Broadband Seismology

1
Portable Broadband Seismology
Part 5 Communication Options

• Jakarta, Indonesia
• May 11-13, 2006
• Bruce Beaudoin
• Marcos Alvarez

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Communication Options
3
VSAT

• Private vs Internet Accessibility
• Link Tuning
• Caveat
• Packet eating
• UDP checksum
• rain fade
• Modem hangs
• High power (gt20W)
• Data rates 256Kbps

4
VSAT Telemetry Deployment
VSAT Terminal
5
DC Powered VSAT Site
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Station Communications Layout

• Seismic site and VSAT Communications separate
  wherever possible - data linked by radio
• Reduces power needs for remote site
• Decreased induced cultural noise from electronics
  and wind
• AC power for satellite system in most cases

Seismic vault layout
Comm system layout

• lt3 Watts DC power
• 75 W solar array
• 2 m vault depth

• 25 Watts DC power
• AC preferred or 500 W solar array
• Up to 50 km radio range

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VSAT Regional Site
VSAT install near barn with AC power
Remote site uses RF radio to telemeter date to
VSAT
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Cell Modem

• Availability of service
• Service providers prefer bursting
• Low power (lt1W)
• Data rate 170Kbps

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Iridium Modem

• Availability of service
• Data rates too low for continuous data
• Caveat
• Link dropouts
• Modem hangs
• Intermediate power (4W)
• Data rate 2.4Kbps

10
Ethernet

• Requires infrastructure
• Low power
• Caveat
• Network security issues
• Data rate 1Mbps (Q330 throttle)

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900 MHz Ethernet Radio

• Line of site only (100 km)
• Point to point
• More tolerant to humidity/rain
• Caveat
• Can be affected by weather
• Low power (1.4W)
• Data rate 115Kbps

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2.4 GHz Ethernet Bridge Radio

• Line of site only (60 km)
• Point to multi-point
• Caveat
• Can be affected by weather
• Other radio interference
• Intermediate power (4W)
• Data rate 10Mbps

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USArray TA Standard Site
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Realtime Date Rates
Rate
40 sps 180 byte/s
40 sps w/OH 360 byte/s
100 sps 450 byte/s
Iridium 300 byte/s
Freewave 15 KB/s
Cell Modem 21 KB/s
VSAT 32KB/s
Wilan 1 MB/s
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Data Volumes
3 channels _at_ 1 sps 11 MB/month
3 channels _at_ 40 sps 475 MB/month
3 channels _at_ 100 sps 1.2 GB/month
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Offload Time for 6 Months of 40 sps Data (3GB)
Rate Time
DAS 10 Mbps 40 mins
Wilan 11 Mbps 37 mins
Baler 0.4 MBps 125 mins
Cell 21 KBps 44 hrs
Iridium 300 Bps 2777 hrs
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Typical Portable DeploymentAnd 1W Power
Consumption (not including sensors)
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Application Serial Telemetry
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Application Ethernet Telemetry
Data Port 1 Net Center 1
Data Port 2 Net Center 2
Data Port 3 status
Data Port 4
Burst or Continuous TX
to status
to Net Center 1
intranet
to Net Center 2
Ethernet
TE
FRAD, DSL,
ISDN, Radio,
VSAT, Dial
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Serial Telemetry with Local Recording
Data Port 1 Net Center 1
Data Port 4 Baler Storage
Data Port 2 Net Center 2
Burst or Continuous TX
Data Port 3 status
Burst or Continuous TX
to status
to Net Center 1
Serial port
TE
to Net Center 2
FRAD, DSL,
ISDN, Radio,
VSAT, Dial
21
LAN-based Telemetry with Local Recording
Data Port 1 Net Center 1
Data Port 2 Net Center 2
Data Port 3 status
Data Port 4 Baler Storage
to status
Burst or Continuous TX
to Net Center 1
to Net Center 2
Ethernet
TE
FRAD, DSL,
ISDN, Radio,
VSAT, Dial
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Remote Digitization with Telemetry to Recording
and WAN Access Site
Data Port 1 Net Center 1
Data Port 2 Net Center 2
Data Port 3 status
Net Center 1
Net Center 2
Burst or Continuous TX
Internet
Status Application
Data Port 1 Net Center 1
Data Port 2 Net Center 2
Data Port 3 status
Data Port 4 Baler Storage
Burst or Continuous TX
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USArray Communications
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GSN II Proposed Configuration