Control M100 only without GPS

I am trying to code a C++ program that will move the drone (DJI Matrice 100) from point A to Point B without using GPS coordinates because I'm testing it inside where GPS signal is non-existent.

I use a DJI Matrice 100 drone equipped with a Guidance and a Manifold.

I analysed the DJI_SDK_DEMO but it's all using GPS coordinates.

Thanks!

I managed to find an answer to my question.

The Matrice 100 doesn't want to fly if the GPS is not activated, so even with no GPS signal, it still needs to be connected. In such environments, the only way to control the drone is with the virtual RC. Documentation can be found here: https://developer.dji.com/onboard-sdk/documentation/Protocol-Documents/virtual-rc-protocol.html

And some example here: https://github.com/dji-sdk/Onboard-SDK-ROS/blob/3.2/dji_sdk_demo/src/client.cpp#L505