after performing a flight I tryed to create the pix4d file from the Pix4D App. However, it always reports an error. So, I decided to take some GCP that covered the internal part of the flight area. After running the first step (following the indications provided by the video-tutorial of the website), I did not manage to use them. I can import the GCP, but I can not relate them to the pictures nor any coordinate. RMS erros are about X=5 Y=10 and Z=0.22.