Emulated GPS data stream broken after PX4 V1.4 update

Hi,

I have been working on Indoor drone application which uses the MarvelMind beacons to feed position data as a replacement for conventional GPS module (such as M8N GPS module). I have been using a Pixhawk 4 and 6C for most of our airframes.

The beacons continously stream emulated GPS data (Ublox protocol) using UART (Tx and Gnd pin) and is connected to the GPS1 port. This works well and I am able to read and use the emulated GPS data for indoor flights and I am able to swap to M8N GPS module for outdoor flights.

However, After the PX4 version 1.14 update, the indoor emulated GPS data has stopped working while the outdoor M8N gps continues to work. In attempt to resolve the issue, I have cross checked all parameters related to GPS config and baudrate checked.
The emulated GPS stream works fine when I roll back to v1.13 and v1.12, but does not work with V1.14. I have replicating the issue on both hardware(Pixhawk 4 and 6C) and they only stop working in v1.14.

@JulianOes , could you please help me with this issue. Happy to provide any additional information.

Thanks in advance.

If MarvelMind decides to use someone else’s protocol, in this case uBlox’s, then they will have to keep up with later versions or changes on the client (PX4) side using it. Given it broke that tells me trying to fake being a GPS was a suboptimal choice.

I would first of all ask MarvelMind to fix the issue.

If they don’t want to help, you will have to look into the GPS, specifically ublox changes, that happened between v1.13 and v1.14 and figure out what broke it.

If you need someone to do the work for you, consider using a PX4 consultant.

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@JulianOes,

Thank you for the speedy response and input😊. I will reach out to Marvel minds regarding this.

I did have a quick look into the changes and could not find much except for support for unicore GPS. I will continue to look deeper into the source code. Any pointers on this will be very valuable.

Many thanks.