# Installing RTK GPS On Sentinel

Source: https://forum.modalai.com/topic/3164/installing-rtk-gps-on-sentinel
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2024-03-03 04:27:26 UTC by SMRazaRizvi
Replies: 9 · Views: 1796

## SMRazaRizvi · 2024-03-03 04:27:26 UTC

Hello All,

I am planning to remove the default M8N GPS onboard my Sentinel drone and replace it with the HolyBro [H-RTK F9P GNSS Series (Helical)](https://holybro.com/products/h-rtk-f9p-gnss-series?variant=41466787168445).

What should my steps be?
Should I unplug the M8N and plug in the H-RTK F9P, or will I have to tweak some params/settings to make it work?

Please help.

Thanks

## Reply by Moderator (ModalAI staff) · 2024-03-03 05:27:26 UTC

@SMRazaRizvi That is not something we have tried so we do not have any way to support you. You might have better luck asking on a PX4 forum

## Reply by SMRazaRizvi · 2024-03-03 20:26:48 UTC (in reply to Moderator)

@Moderator 

Have you tried integrating any other RTK GPS?

## Reply by Eric Katzfey (ModalAI staff) · 2024-03-04 17:17:19 UTC (in reply to SMRazaRizvi)

@SMRazaRizvi We have not.

## Reply by SMRazaRizvi · 2024-03-05 14:58:23 UTC (in reply to Eric Katzfey)

@Eric-Katzfey Can you guide me on how to integrate any other GPS module with the Sentinel drone?
I can get some insights from that process.

## Reply by Eric Katzfey (ModalAI staff) · 2024-03-05 16:22:48 UTC (in reply to SMRazaRizvi)

@SMRazaRizvi Which one? Are you not satisfied on the one supplied with Sentinel? Sentinel is a reference design that shows how to use a GPS module. Take a look at the px4 start file for voxl2 in `/usr/bin/voxl-px4-start`

## Reply by SMRazaRizvi · 2024-03-06 17:17:13 UTC (in reply to Eric Katzfey)

@Eric-Katzfey I want to integrate this RTK-GPS: https://holybro.com/collections/standard-h-rtk-series/products/h-rtk-unicore-um982 with Dual Antenna setup to get more accurate positioning.

## Reply by Alex Kushleyev (ModalAI staff) · 2024-03-07 14:51:34 UTC (in reply to SMRazaRizvi)

@SMRazaRizvi , is this GPS module already supported by PX4 (is there a software driver for it in standard PX4 build)? we have not used this one before).

## Reply by SMRazaRizvi · 2024-03-07 19:34:58 UTC (in reply to Alex Kushleyev)

@Alex-Kushleyev Yes it's supported by PX4.

## Reply by SMRazaRizvi · 2024-03-07 19:47:20 UTC (in reply to SMRazaRizvi)

@SMRazaRizvi Actually connecting my RTK-GPS to the configuration described here: https://docs.modalai.com/voxl2-guides-onboard-offboard-sensors/#external-gps-mag--gnss was not giving me RTK corrections so I am now using the J9 connector on the 5G modem, and that works fine in giving me GPS Coordinates and receiving RTK Connections.

But another problem that I am facing is `Compass Sensor 0 missing`.
Do you think there's some setting of the default compass that PX4 was picking up with the M8N GPS that came with the drone? Where can I configure the compass?