The setup is a Pi, a Navio2 and an Auterion GPS with F9P controlled by a herelink.
As the herelink uses the UART for telemetric stuff, the GPS needs to go into the I2c. According to the F9P datasheet, the ublox by default sends gps data by i2c too. I2C connections seem to be OK as the RGB LED mimicks the Navio2 LED when ardurover is started. I2c check reports address 38 when the GPS is plugged in. This corresponds to e.g. BMA150, which would make sense. The F9P datasheet has a chapter about i2c, but I cannot find an address. On the other hand, there is a note that says: “When the I2C slave is stretching the clock …”. Is the ublox i2c master? At least it is not recognised by ardurover. I tested the Auterion GPS via UART and it works. So, electrically it should all be fine. Do I need to configure the GPS in /etc/default/ardurover.conf in a special way to have it try the GPS at i2c as well?
I don’t think AP supports any I2C GPS, nor am I aware of an existing I2C driver to transmit RTCM3 over I2C. You’ll have to make significant modifications to make that happen. The Navio2 is likely not a good choice for your application, given its lack of peripheral ports.
Thanks for the info. The navio is a must for me as it -according to my knowledge- is unrivalled in the number of Servo outputs. I need these. As I work with a Pi it is no problem to add a USB to uart. Problem solved, works like a charm.
Glad you found a solution.
But…12 servo outputs is pretty much standard on modern AP-compatible autopilots, and there are plenty from which to choose.
Considering that we need a Pi (it has to run other nondemanding stuff as well), the only valid alternative I see in a quick search is the Navigator by BlueRobotics. But never mind, this might divert the discussion into an unwanted direction. The problem is solved, I get a GPS with just some centimeters positional error, so I’m happy with it.
I understand but didn’t want to propagate misinformation to others that the Navio2 somehow exceeds the average STM32-based autopilot’s available outputs (at least the larger form factor variants).