RTK Input to GPS2, Format Question

I’ve got RTKLIB running on a Beaglebone Black (BBB) linux board, and am ready to send the solution to my PixHawk2 GPS2 connector via a USB port on the BBB. Do I send the output in NMEA format? Do I need to make a special cable, like USB-to-FTDI-to-GPS2?


It’s been a long while since I’ve done anything on my bbb but from memory there are 5 available uarts you could use to output your solution to one of the Pixhawk serial ports. I’m sure you could output over the usb but you would then need a USB/serial adapter (such as ftdi). Using a standard uart on one of the gpio pins would be a direct connection. It has also been a while since I have used RTKLib so not too sure what output formats it now supports. NMEA will work

unfortunately I’m using a cellular cape (for the base station link) which takes up the BBB UARTs. The rover GPS plus into the regular BBB USB. So my plan is to use the BBB micro-USB output, maybe through FTDI (like you mentioned) and then into a JST-GH connector for the PixHawk2 GPS2 plug. That’s my thinking, but requires I make a microUSB-to-FTDI-to-GPS2 cable.

RTKLIB has a couple of format outputs, primarily one called Solution (LLA or XYZ) and NMEA. So hoping the NMEA format works.

Don, what cape are you using? Does it not pass through any pins? That would be a pretty limiting factor for any cape… You could solder from the underside - only one connection required if your devices share a ground. I use an rtk gps outputting NMEA into a serial port just fine. Just remember to set the gps type in your Ardupilot software.

Have this cape ordered:


Should arrive in a day or so. Doesn’t pass through pins so could solder lines from below or above I suppose.

Looks like all you have are the J9. J10 ‘Grove’ connectors giving access to GPIO03, GPIO05 and GPIO06. You could try bit banging serial out one of these pins or maybe look at a pin change interrupt on an unused uart tx pin (P9_24 - uart 1) and echo the output to one of the GPIO pins… I would just solder directly to a TX pin :slight_smile:

Update… The cellular cape (and cell module) for the Beaglebone Black (BBB) from Digikey is on indefinite backorder, so I’m switching temporarily to a Beaglebone Black Wireless for my RTK rover. This BBB Wireless has on-board wifi, so will stream the RTK base station data to the rover via wifi for now. Will switch to cellular when the modules become avail.