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  • Micromodem Overview
  • Installation, Testing, Troubleshooting
  • Usage Scenarios
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Usage Scenarios

Micromodems in the Field - Multi-System Use

Micromodems in the Field – Multi-System Use

Micromodems in the Field – Multi-System Use

The Micromodem has been used in several situations where there have been multiple vehicles, multiple bottom mounted sensors, multiple ships and buoys all working cooperatively together in one or more frequency bands. The Acoustic Communications Group has hardware solutions for most applications. Please see the simplified scenarios that follow to see if your application is similar.

Micromodems in the Field - Boat to Vehicle

Micromodems in the Field – Boat to Vehicle

Micromodems in the Field – Boat to Vehicle

In this scenario, a topside modem kit installed on a small boat or ship communicates via an over the side transducer towfish to an underwater vehicle with modem kit installed.

Typical Equipment Required (assumes 25kHz Mulit-Channel PSK operation):

Topside (i.e. on Boat)

  • 258060 Pelican Deck Box (battery powered splash proof enclosure) or 252080 RHIB Deck Box (battery powered submersible enclosure)
  • 224001 Transducer Towfish
  • 234052-50ft Cable: Transducer and Array Load Bearing – 50ft Length
  • 211002 Transducer: WH-BT-2
  • 214008 Array: HTI-96-MIN (CM) 4 Element Inline Array
  • 205032-0222 Multi-RX PSK Micromodem 2 RFF Stack with Wide Input for 211002 Transducer

Vehicle (Assumes modem is installed in vehicle electronics bay or similar, we have several stand alone housings available):

  • 205032-0222 Multi-RX PSK Micromodem 2 RFF Stack with Wide Input for 211002 Transducer
  • 211002 Transducer: WH-BT-2
  • 214008 Array: HTI-96-MIN (CM) 4 Element Inline Array
Micromodems in the Field - Boat to Buoy

Micromodems in the Field – Boat to Buoy

Micromodems in the Field – Boat to Buoy

In this scenario, a topside modem kit installed on a small boat or ship communicates via an over the side transducer towfish to a VSW Modem Buoy with modem kit installed. This application is typically used by the Acoustic Communications Group to measure the performance of the acoustic channel prior to vehicles or sensors getting in the water.

Typical Equipment Required (assumes 25kHz Mulit-Channel PSK operation):

Topside (i.e. on Boat)

  • 258060 Pelican Deck Box (battery powered splash proof enclosure) or 252080 RHIB Deck Box (battery powered submersible enclosure)
  • 224001 Transducer Towfish
  • 234052-50ft Cable: Transducer and Array Load Bearing – 50ft Length
  • 211002 Transducer: WH-BT-2
  • 214008 Array: HTI-96-MIN (CM) 4 Element Inline Array
  • 205032-0222 Multi-RX PSK Micromodem 2 RFF Stack with Wide Input for 211002 Transducer

Buoy (Maximum Operating Depth 100ft unless in drifter application):

  • 255011-3RB VSW Modem Buoy with (3) Rechargeable Li-Ion Batteries, GPS and 900MHz Freewave
  • 234052-50ft Cable: Transducer and Array Load Bearing – 50ft Length
  • 211002 Transducer: WH-BT-2
  • 214008 Array: HTI-96-MIN (CM) 4 Element Inline Array
  • 205032-0222 Multi-RX PSK Micromodem 2 RFF Stack with Wide Input for 211002 Transducer
Micromodems in the Field - Buoy to Vehicle

Micromodems in the Field – Buoy to Vehicle

Micromodems in the Field – Buoy to Vehicle

In this scenario, a VSW Modem Buoy with modem kit installed communicates to an underwater vehicle with modem kit installed. The user communicates to the buoy via and RF link. The buoy communicates to the vehicle via an acoustic link.

Typical Equipment Required (assumes 25kHz Mulit-Channel PSK operation):

Buoy (Maximum Operating Depth 100ft unless in drifter application):

  • 255011-3RB VSW Modem Buoy with (3) Rechargeable Li-Ion Batteries, GPS and 900MHz Freewave
  • 234052-50ft Cable: Transducer and Array Load Bearing – 50ft Length
  • 211002 Transducer: WH-BT-2
  • 214008 Array: HTI-96-MIN (CM) 4 Element Inline Array
  • 205032-0222 Multi-RX PSK Micromodem 2 RFF Stack with Wide Input for 211002 Transducer

Vehicle (Assumes modem is installed in vehicle electronics bay or similar, we have several stand alone housings available):

  • 205032-0222 Multi-RX PSK Micromodem 2 RFF Stack with Wide Input for 211002 Transducer
  • 211002 Transducer: WH-BT-2
  • 214008 Array: HTI-96-MIN (CM) 4 Element Inline Array
Micromodems in the Field - Buoy to Node to Vehicle

Micromodems in the Field – Buoy to Node to Vehicle

Micromodems in the Field – Buoy to Node to Vehicle

In this scenario, a ship communicates via and RF link to a buoy which communicates acoustically (25kHz) to a bottom mounted node acting as a repeater. The node then communicates acoustically (10kHz) to another bottom mounted node acting as a repeater. The second node then relays the message acoustically (25kHz) to the vehicle. All systems could operate in the same frequency band depending on the relative spacing of the various systems. The dual band concept has worked well in short range cells with long range hops between cells.

Typical Equipment Required (assumes 25kHz (short range) and 10kHz (long range) Mulit-Channel PSK operation):

Buoy (Maximum Operating Depth 100ft unless in drifter application):

  • 255011-3RB VSW Modem Buoy with (3) Rechargeable Li-Ion Batteries, GPS and 900MHz Freewave
  • 234052-50ft Cable: Transducer and Array Load Bearing – 50ft Length
  • 211002 Transducer: WH-BT-2
  • 214008 Array: HTI-96-MIN (CM) 4 Element Inline Array
  • 205032-0222 Multi-RX PSK Micromodem 2 RFF Stack with Wide Input for 211002 Transducer

Bottom Node (Assumes 25kHz is used for short range communication and 10kHz is used for long range communications)

  • 252060 Node, Dual Band, (5x Li-Ion Batteries ~1kWhr)
  • 223508 Cage for Dual Band Node
  • 223100 Transducer: ITC-3013 with Backing Block
  • 211002 Transducer: WH-BT-2
  • 214008 Array: HTI-96-MIN (CM) 4 Element Inline Array
  • 205032-0222 Multi-RX PSK Micromodem 2 RFF Stack with Wide Input for 211002 Transducer
  • 205032-0815 Multi-RX PSK Micromodem 2 RFF Stack with Wide Input for 211002 Transducer
  • 205049 Gumstix Interface Board with Gumstix Computer

Vehicle (Assumes modem is installed in vehicle electronics bay or similar, we have several stand alone housings available):

  • 205032-0222 Multi-RX PSK Micromodem 2 RFF Stack with Wide Input for 211002 Transducer
  • 211002 Transducer: WH-BT-2
  • 214008 Array: HTI-96-MIN (CM) 4 Element Inline Array
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Documentation & Support

  • Micromodem DSP Mainboard
  • Micromodem Software Interface and Firmware
  • Micromodem Power Amplifier
  • Micromodem Coprocessor
  • Micromodem Multi-Channel Analog Interface
  • Bare Board Systems
  • Software Development Boxes
  • Deck Boxes
  • Pressure Vessels, Buoys
  • Transducers, Arrays and Towfish
  • Iridium Interface Board
  • Precision Timing Board
  • Gumstix Computer Interface
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