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DVL-75
DVL-75
  • DVL-75
  • Overview
    • General Specifications
    • General Use Cases
    • The Basic System
    • System Components
    • Comparison of Tracker 650 and DVL-75
  • Usage Considerations and Scenarios
    • General Usage
    • Scenario: GPS Emulation
    • Scenario: Holding Position
    • Scenario: Autonomous Waypoint Navigation
    • Scenario: Returning to a Series of Known Positions
    • Scenario: Returning to Home
    • Scenario: Using GPS Assist
    • Scenario: Doing Your Own Dead Reckoning
    • Additional Connection Possibilities
    • General Hints and Tips
    • Operation in a Pool
  • Using MAVLink and BlueOS for Position Hold on a BlueROV2
    • ArduPilot Parameters
    • DVL Setup for MAVlink Support
  • Using Other Than the Bottom for the DVL (Side-Tracking Capability)
    • Side-Tracking Capability Design Use-Cases
    • Side-Tracking Capability Considerations
  • Mounting the DVL Components
    • Sensor Head Typical Mounting
    • Sensor Head Side-Tracking Mounting Alignment
    • All-in-One and Most-in-One Mounting Considerations
    • Mounting the Electronics Stack
    • Mounting an Auxiliary GPS
  • Assembling the Electronics Stack
    • Cerulean 300m Electronics Enclosure Assembly
  • Inertial Measurement Unit (IMU)
    • Baseline IMU Calibrations
    • Baseline IMU Background
    • Baseline IMU Blind Initial Calibration Procedure
    • Baseline IMU Status-Assisted Initial Calibration Procedure
    • Baseline IMU Calibration for Each Mission or Each Time Power is Applied
    • Upgraded IMU Calibration for Each Mission or Each Time Power is Applied
  • Communicating with the DVL
    • Factory Defaults and Default Messages
    • The Ethernet Interface
    • Tips on How to Find the IP Address Assigned to Your Ethernet Adapter
    • The Serial Interface
    • Resetting the Communications Parameters to Factory Default
    • What Do the LEDs Mean?
    • Outgoing Message Formats, DVL to Host
      • $GPRMC: NMEA standard Recommended Minimum GPS/Transit Data
      • $DVEXT: DVL Extended Data
      • $DVPDL: DVL Position and Angle Deltas Message
      • Freeform Error and Informational messages ($DVTXT)
      • Re-Tweeted GPS Messages
      • Re-Tweeted IMU Messages (IMU Raw Data)
      • $DVKFA, $DVKFB Kalman Filter Support Messages
        • Driving your own Kalman Filter
    • Commands Accepted by the DVL
      • $GPRMC
      • SET-POSITION
      • CONFIGURATION
      • SUPPRESS-GPS
      • DECLINATION
      • SET-SPEED-OF-SOUND
      • SET-VELOCITY-ADJUSTMENT
      • SEND-GPRMC
      • SEND-DVEXT
      • SEND-DVKFA
      • SEND-DVKFB
      • SEND-FREEFORM
      • SEND-DVPDL
      • RETWEET-GPS
      • RETWEET-IMU
      • SET-SENSOR-ORIENTATION
      • GRAB-IMU-CAL
      • VOID-IMU-CAL
      • BAUD-RATE
      • IP-ADDRESS
      • HOST-ADDRESS
      • MAVLINK-ADDRESS
      • FALLBACK-ADDRESS
      • UNICAST-TO-ME
      • PAUSE
      • RESUME
      • REBOOT
    • Blue Robotics Ping360 Discovery Protocol (Ethernet Only)
    • ARP (Address Resolution Protocol)
    • DHCP (Dynamic Host Configuration Protocol)
    • Ping (Internet Control Message Protocol Ping)
    • Mechanical Drawings
      • Mounting Dimensions, Sensor Head
      • Mounting Dimensions, Electronics Stack
      • RAM Mount Adapter Plate
      • Electronics Stack Assembly Drawing
      • Mounting Bracket for 300m Electronics Enclosure
      • Mounting Bracket for Sensor Head or Electronics Enclosure, fits BlueROV2 Heavy Thruster Guard
      • Mounting Bracket for All-in-One Enclosure, fits BlueROV2 Heavy Thruster Guard
      • Mounting Dimensions, Cerulean 300m Enclosure
      • Mounting Dimensions for the Cerulean All-in-One Enclosure
      • Mounting Dimensions, Cerulean GPS
  • Electrical Drawings
    • Serial Cable Supplied with Baseline Electronics Stack
    • DVL Serial Connection Example
    • Power over Ethernet (POE) Cabling
    • Standard Ethernet Pinouts
    • Optional GPS Wiring
    • Sensor Head Wiring
    • Using External Power with Serial Cable
    • Serial to USB Interface Using Blue Robotics BLUART Board
  • CAD Models
  • Appendix – Coordinate Systems
  • Copyright
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  1. Usage Considerations and Scenarios

Scenario: GPS Emulation

PreviousGeneral UsageNextScenario: Holding Position

Last updated 3 years ago

The focus of many ROV users is on underwater exploration, not on the nuts and bolts of integrating new electronics with an already-complex set of hardware and software. The Cerulean DVL can emulate a standard GPS (it comes from the factory already set to do so). This is accomplished by setting the DVL to send only the NMEA-format $GPRMC message. All other data output, information messages, and warning messages are suppressed. The emulation works on both serial and Ethernet interfaces.

Note that the DVL can’t magically geo-locate all by itself. At power-up, it therefore begins life thinking it is at latitude/longitude (0N,0E), which is somewhere off the coast of Gabon, Africa. You can continue to operate using relative changes from (0,0), or you can operate in true latitude/longitude by setting a new initial position using a known starting location [the optional GPS can automatically provide an initial position].

What this requires in addition to the DVL: For operation relative to (0,0), connect the serial output of the DVL to a serial port where your ROV software is expecting to find a GPS. To operate in true latitude/longitude, you can then send a starting position from your own GPS to the DVL, you can add an optional GPS directly to the DVL and let the DVL manage it (the GPS should be located on the ROV so it loses fix when the ROV submerges), or you can send a position fix directly to the DVL when the ROV is at a known location like a waypoint.

Also, see the introductory discussion of the IMU for additional considerations for this scenario.

GPS Emulation. The “Serial-RX” line connects to the ROV port that expects a GPS to be connected. In this scenario, the Serial-TX line (sending from the ROV Systems to the DVL) need not be connected. This is probably the simplest DVL interconnection schema.
GPS Emulation, Take 2. The “Serial-TX” line can be added (the other half of the serial interface), probably connected to a different serial port on the ROV Systems than the Serial-RX of the GPS emulation. Now, you can continue to use the GPS emulation, but you can use the TX port to send data to the DVL, such as position updates.