The Instrument Manager and GPS Support
The Instrument Manager allows you to access streams of data being fed into your computer from NMEA-compatible instruments. NMEA is an acronym for the National Marine Electronics Association, which determines communication protocols for marine devices. The oldest but still most commonly used protocol is NMEA 0183, which is a serial protocol transmitted over (something very close to but not exactly) RS232 connections.
BLUEWATER will read and process NMEA 0183 data from up to five serial input streams. Each stream comes into a separate serial communications (comm) port on the computer. Modern computers normally do not have DB9/RS232 serial ports, but serial streams are sent over USB or Bluetooth connections. RS232 to USB adapters that create "virtual" serial ports on your computer are available from large electronics distributors
To enable reading this serial data, enter the comm port identifiers into the NMEA Serial entries and click the corresponding “Enable” boxes. Under Windows, comm ports are typically identified as COMn: for some integer n. For example, COM1:, COM8:, etc. To find the list of available comm port names, you should consult the Windows Device Manager. Note that two-digit comm ports (e.g. COM12:) may not work. The actions that the program is taking to connect will appear in the “Actions” window.
Under Unix and Mac OSX, serial ports appear in the /dev directory, and have names such as "/dev/ttyp0" or "/dev/cu.Bluetooth-Incoming-Port". When a serial adapter creates a virtual serial port, if may create both a /dev/tty* and a /dev/cu* type port. You should use the /dev/cu* ports.
If one of the streams comes from a GPS that is set to communicate in NMEA 0183 mode, then GPS position and course information will be displayed on the upper toolbar. In addition, the GPS_pos waypoint will be created and updated, and positions will be added to GPS_track. The frequency with which positions are added to the track is determined by the “Track Update Freq”, which is the number of seconds to wait before a new position is added.
You can view the data that is being received from the instruments by clicking on “View Raw NMEA”. You can also log the actual NMEA messages to a file by enabling the “Raw Log File”. This file will get big quite fast.
Many GPS units connect to computers via a USB cord to allow you to copy route files to and from the unit. Often GPX is supported by these units. Otherwise, you can export to many formats using GPSBabel.
BLUEWATER can also connect to certain Garmin GPS using the Garmin proprietary two-way protocol. This can occur over a RS232 or usb connection. If Garmin protocol is available, you may right-click on a route (either in the Route Manager window, or on the chart in edit mode) and upload it to the GPS. In addition, under Tools→GPS you can download all routes and waypoints from the GPS into BLUEWATER or you may upload all routes and waypoints in the current race to the GPS. In addition, position and course data will be downloaded continuously.
To set up a Garmin protocol connection, specify and enable a port in the “Garmin port” entry on the Instrument Manager. For Windows, it will be a serial port such as “com1:”, or a usb port such as “usb:”, depending on how your GPS unit connects to the computer. Don’t forget to set your GPS to communicate in Garmin protocol. BLUEWATER provides Garmin proprietary support through a helper program, gpsbabel. Please visit www.gpsbabel.org for more information about this program. Their online manual may be helpful in resolving any Garmin communication issues.