The main scope of the GeoSpectrum project is to develop a system that allows dynamic access of secondary (unlicensed) radio equipment to radio frequency spectrum, based on accessing spectrum geolocation databases that contain information regarding the availability of different frequency bands depending on the geographic location. The designed and implemented system will be flexible and scalable, allowing the addition of new services/information and the extension of the covered geographical area. Three pilot areas (an urban, a suburban and a rural one) will be chosen as target for the envisioned system, to illustrate its feasibility in different environments. The radio coverage for different primary (licensed) radio networks (DVB-T2, 2G/3G/4G/5G) will be estimated using the HTZ Communications software and several propagation models. For validating and optimizing the estimations, measurement campaigns will be conducted in all the pilot areas. Afterwards, the spectrum geolocation databases will be designed and implemented, using spectrum availability data extracted from the coverage maps. Blockchain-based mechanisms for accessing the databases will also be developed. Moreover, hybrid spectrum sensing methods will be developed, which combine local sensing with data read from the spectrum geolocation databases. The GeoSpectrum system will be tested in several different use cases and scenarios, for all the pilot areas, to validate its performance and robustness.