## 1 Introduction
However, all these case studies are based on the use of field data to train implemented algorithms, but these data are not always available, and the dependence on this information does not allow the development of an operational crop mapping service. Crop mapping remains a complex task for operational activities, is still highly dependent on field data, and relies on local knowledge of management practices [21]. It is of paramount importance to develop a methodology for crop mapping that is mostly based on the intrinsic properties of the crops and their phenology rather than on field data. In addition, the most used SAR data are in the C band, with a lower spatial resolution than the X band's data resolution. Some improvement can be provided by the recent development of a new constellation of X-band sensors, significantly contributing to crop mapping thanks to higher spatial and temporal resolutions [6]. From this perspective, the development of an automated processing chain is necessary, especially to fulfill users' need for targeted agricultural EO products with recurrent and frequent data to produce seasonal and annual information. This evaluation has provided important insights for the development of new sensors, also considering the investments planned by the European Union for further satellite missions [22]. Contextually, the Copernicus program delivers environmental information largely based on EO satellite data in the form of Copernicus Services, addressing six thematic areas. Copernicus operational services are not static but need to evolve with emerging user requirements and state-of-the-art methodologies for developing and testing algorithms for pre-operational and operational product prototypes and improving and developing future-specific Copernicus services with the potential for global applications [23]. It is paramount to bridge the gap between the user requirements and the technical limitations of existing sensors by developing applications for the new generation of satellites. The NOCTUA project was a pilot project for the development of a commercial service for collecting, processing, and distributing radar data designed for the Lombardy region (Northern Italy). This project foresaw the development of a new Low Earth Orbit (LEO) SAR satellite in the X band, with a revisit time of 11 days and a ground resolution of less than 1 m (in Spotlight mode). NOCTUA has been considered a Proof of Concept (POC) of the IRIDE NEXTGENERATION EU investment, which will develop an Italian LEO satellite constellation called IRIDE. This constellation will provide a downstream service at the national level to supply data from different types of sensors (multi-, hyperspectral, infrared, SAR), also considering existing missions, and to develop a series of operational services in several application domains: coastal, air quality, water resource, land cover, etc. Several methodologies for crop mapping and monitoring have been developed in recent years. However, the shortcomings for operational use have not been broadly explored. A valuable use of crop mapping and monitoring algorithms exploiting EO data from the perspective of consistent operational product development and demonstrating a clear configuration of technical and operational users' requirements of the relevant aspects of an operational service provision is still lacking. Thus, the main objective of this study is to develop a Proof of Concept (POC) of a pre-automatized processing chain based on a multi-sensor approach for crop mapping with the purpose of being potentially integrated into an operational service architecture, boosting the possibility of addressing users' needs, with respect to their urgency, the closeness to the operational delivery process, and the availability of capacities. The integration of high-resolution SAR in X-band imagery and multispectral optical data has been explored to analyze the phenological stages of the crops, using an agricultural area located in the Lombardy region as a test site.