GPS to n2k

[newbie-]

Is it possible to relay a usb GPS used for OpenCPN to a NMEA 2000 network? Obviously I'll need a bidirectional gateway.

But how could I push the sentences to the n2k network?

[nohal]

That is what the bidirectional gateway, like https://www.quark-elec.com/product/q...ional-gateway/ does.
The setup you want is somewhat unusual though, a standalone NMEA2k complatible GPS connected to your N2k backbone is usually considered a better, more power effective and sure more reliable solution.

[newbie-]

I'm thinking it's more of a backup solution. I have 3 USB GPS units on board. They're inexpensive and available everywhere. But they can only interface with a pc.

It would be handy (and probably simple) to have the option to relay that to the nmea backbone if ever necessary.

I have that same QE gateway here with me

[nohal]

For this type of cheap DIY backup you probably want to replace the GPS with USB output and the PC with a GPS with UART output and a UART-to-RS422 converter (Both available for a few bucks on ebay, aliexpress etc.).

[fgd3]

Isn't it true that the USB GPS receivers draw power from the USB port and dump a stream of NMEA 0183 sentences back along the USB cable? What would it take to feed that signal to an NMEA 0813/NMEA 2000 bidirectional gateway? It may be possible to interface the GPS directly to the gateway without requiring a PC.

[nohal]

That migh or not work, depending on the parameters of the USB port on the gateway. In USB communication one end of the connection must act as a host, the other as a device. The USB ports of a PC are host all the time. Some eg. phones do some magic when the OTG cable is connected and switch between device and host mode as a pin is pulled to ground. What the gateway does we don't know.

[stevead]

The beta release of the next version of the TwoCan plugin supports this scenario.

It converts NMEA 0183 sentences received by OpenCPN into the equivalent NMEA 2000 PGN's and transmits them onto the NMEA 2000 network.

You will require a supported CAN bus adapter for the PC/Operating System that you are using, as well as, obviously, a USB GPS device that works with OpenCPN.

But if you already own the Quark gateway, why not use that ? Configure OpenCPN to output NMEA 183 data to the port that the gateway is configured to use.

[newbie-]

Originally Posted by stevead

But if you already own the Quark gateway, why not use that ? Configure OpenCPN to output NMEA 183 data to the port that the gateway is configured to use.

Hmm. That sounds perfect! It looks like the the OpenCPN output is meant for autopilots but it does seem to contain the GPS position too. The QE gateway should then send it to the N2K backbone.

Haven't tested this yet.