This project presents the proof-of-concept of the new cost-effective Earth remote sensing GNSS-DIRECT payload, suitable for small satellites such as CubeSats. This new instrument has been designed at ESEIAAT-UPC (http://eseiaat.upc.edu/ca) during a Final Degree Project, and it will be tested for first time during a stratospheric sounding balloon experiment. The processing technique implemented in the GNSS-DIRECT payload can provide accurate GNSS Radio- Occultation (GNSS-RO) observations of the atmosphere. Simultaneously, GNSS Reflectometry (GNSS-R) measurements of the Earth surface can be collected for grazing angles, when coherent scattering effects provide strong forward scattered GPS signals. Results from this experiment will be investigated to determine the degree of signal coherence over land surfaces from a high altitude, and low speed platform. This scenario will provide a unique opportunity for research, and conclusions could be useful to improve our understanding on the use of GNSS for remote sensing.