Adding GPS data automatically to DVL data in QGC

Hello everyone,

I have bought DVL A50 and NEO-M8U gps module and my task is to use the data of gps when the vehicle is at the surface of water and again use that data to improve the accuracy of DVL A50 data when the vehicle is submerged under the water. I am using BlueOS Software and QGround Control to monitor the vehicle.
How can I achieve it? Suggestions and solutions are welcomed

Thanks