goby-zeromq: Goby Visualization Interfaces

A key part of operating autonomous marine vehicles is the ability to visualize their locations. Goby provides interfaces to existing visualization tools for displaying marine vehicles.

goby_geov_interface

The GEOV project: https://github.com/GobySoft/geov lets you run a local server that provides data to Google Earth Pro.

The goby_geov_interface provides a client to the GEOV server to input vehicle position data from Goby3.

The key subscription for goby_geov_interface is:

- group: goby::middleware::frontseat::node_status
  scheme: PROTOBUF
  type: goby::middleware::frontseat::protobuf::NodeStatus

Using the data from node_status, the correct MySQL insert is performed for GEOV.

Configuration variables are:

• simulation: If true, writes to GEOV as a simulation data source (default: false)
• mysql_host: IP Address or domain name for GEOV MYSQL server
• mysql_user: User name for GEOV input
• mysql_password: Password for GEOV input
• mysql_port: Port for GEOV MYSQL server
• position_report_interval: Seconds between position reports to enter into GEOV for a given vehicle (default: 1)

Publish/Subscribe API Diagram

goby_opencpn_interface

OpenCPN is an open source Chart Plotter Navigation software. This allows you to easily display other vessels, support vessel GPS position, ENC and RNC nautical charts, etc.

The goby_opencpn_interface allows you to input autonomous vehicle positions into OpenCPN as if they are AIS positions, without having to modify OpenCPN to do so.

OpenCPN setup

Install OpenCPN:

sudo add-apt-repository ppa:opencpn/opencpn
sudo apt-get update
sudo apt-get install opencpn

Add charts (for example all of Massachusetts):

Options: Charts
    Chart Downloader
        Add Catalog
        USA - NOAA & Inland Charts
            ENC -> by States -> MA
            Update
            Download Charts…
                Download selected charts
        Apply
    Chart Files
        Prepare All ENC Charts

Add connection:

Options: Connections
    Add connection : Network
    TCP: 127.0.0.1 Port 54000

Show AIS target tracks and names:

Options: Ships: AIS Targets
    Check: Show target tracks, length (min): 20
    Check: Show names with AIS Targets at scale greater than 1: 250000

goby_opencpn_interface Configuration

The only significant configuration setting required is

ais_server {
    bind_port: 54000
    set_reuseaddr: true
}

Where the bind_port needs to match the port configured in the Connections tab of OpenCPN (previous section).

Publish/subscribe

The key subscription is the same as goby_geov_interface:

- group: goby::middleware::frontseat::node_status
  scheme: PROTOBUF
  type: goby::middleware::frontseat::protobuf::NodeStatus

From the node_status, goby_opencpn_interface creates spoof AIS messages for this vehicle and sends them to all connected clients (OpenCPN in this case).

goby_geov_interface can also publish two variables:

- group: goby::middleware::opencpn::route
  scheme: PROTOBUF
  type: goby::middleware::protobuf::Route
- group: goby::middleware::opencpn::waypoint
  scheme: PROTOBUF
  type: goby::middleware::protobuf::Waypoint

These are published if you create a Route or Waypoint, respectively, in OpenCPN and then right click on it, choose "Send to GPS" and send it to the same port as goby_opencpn_interface (in the example above that would be "TCP:127.0.0.1:54000").

These publications can be mapped onto data fields in goby_liaison using the "External Data" functionality. This allows you to send positions and routes using the OpenCPN mapping software rather than manually entering latitude/longitude values into goby_liaison Commander.

Publish/Subscribe API Diagram