Being a catamaran owner, I naturally like to have two of everything. So ever since I started playing around with OpenCPN, I've been meaning to hook up an external GPS to provide me with a backup to my Raymarine e7D chart plotter (a.k.a. "multi-function display" or "MFD"). I was rudely reminded of this last week when my e7D's built-in GPS gave up the ghost on the eve of a 4-day cruise.
Fortunately, I had a GlobalSat MR-350 GPS receiver ready to go which I just had to hook up. (Amazon sells them for ~US$60 which is about as cheap as you can get for a waterproof, serial GPS).
|GlobalSat MR-350 GPS receiver mounted in front of helm.
|Simple GPS power/interface circuit.
Next, I connected the RS232 output to my boat computer, except, like most laptops, mine lacks a serial port thereby necessitating the use of a USB port with a serial-to-USB converter. On Windows, once the drivers are installed you'll see a new COM port under Ports in Device Manager. (The MR-350 uses the Prolific PL2303 chip and the standard PL2303 USB to serial drivers).
The final step is configuring OpenCPN to use the new COM port, which is under Settings/Connections. OpenCPN is then ready to be used as a chart plotter.
OpenCPN's "Navigate to this" feature works like a charm, providing the familiar XTE (Cross Track Error), BRG (Bearing), VMG (Velocity Made Good), RNG (Range), TTG (Time to go), etc.
|OpenCPN in navigation mode.
While OpenCPN doesn't have all the features of my e7D, it's very reassuring having a completely redundant chart plotter.