# Adding GNSS libmodal pipe interface

Source: https://forum.modalai.com/topic/4987/adding-gnss-libmodal-pipe-interface
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2026-01-15 18:29:30 UTC by jon
Replies: 1 · Views: 301

## jon · 2026-01-15 18:29:30 UTC

I'm in the process of building an apps proc mpa server sensor package for the vectornav vn300 external INS, and looking through the currently supported interfaces in libmodal pipe there appears to be no GNSS interface. It seems pretty simple to add a header, but taking the imu_data_t interface as an [example](https://gitlab.com/voxl-public/voxl-sdk/core-libs/libmodal-pipe/-/blob/master/library/include/pipe_interfaces/imu_data_t.h) I can't find where the pipe_validate_imu_data_t() function is defined, so it's unclear to me how it actually validates a pipe read, and how I would do it for a gnss data stream with different fields. 

Maybe I'm just not looking in the right place? Please let me know where I can find an example of pipe data validation, and also of any other requirements when adding an interface to libmodal pipe.

Thanks!

## Reply by Eric Katzfey (ModalAI staff) · 2026-01-15 23:11:50 UTC

@jonathankampia https://gitlab.com/voxl-public/voxl-sdk/core-libs/libmodal-pipe/-/blob/master/library/src/interfaces.c?ref_type=heads#L72