Ultra-high energy cosmic rays are messengers of the most powerful events in the Universe. In the last years there has been a remarkable progress in this field. However the astrophysical sites and the mechanism to accelerate cosmic rays at macroscopic energies and the nature of these particles are still unknown. To advance in the knowledge of the origin of cosmic rays, larger statistics and a better determination of the mass composition are required.The goal of this project is to investigate possible detector improvements for the observation of the signals left by the secondary particles produced in the interactions of cosmic rays with air nuclei in the atmosphere. In the short term the project explores ways to enhance the leading experiment Pierre Auger Observatory. In the long term those improvements can be used as the base for the development of the next generation ground-based detectors. The investigations are focused on water-Cherenkov detectors. The proposed improvements aim at obtaining a better resolution in the determination of the muon content reaching ground. This will provide a better mass composition sensitivity. The use of new photosensors, the silicon photomultipliers, in cosmic rays experiments is also addressed. A novel technique to measure cosmic ray signals from the molecular bremsstrahlung in the GHz frequency range could prove to be a viable solution for the next generation detectors. The project includes the participation in the determination of the feasibility and overall performance of this technique.