## 4 Conclusions  
This work arises from the continuing need to reduce operational costs and, at the same time, increase floating offshore efficiency. The smart sensor forms part of the MooringSense project that aims to achieve these goals, developing an efficient risk-based integrity management strategy for mooring systems based on affordable and reliable online monitoring technology. Several tests at different scales were carried out to verify the good performance and suitability of the smart sensor and the algorithms developed. These tests verify its viability for use in real-time monitoring of offshore platforms. All the measurements carried out, starting from the static mode to the validation in the real environment, have shown that the developed system successfully complies with the specifications imposed by the application: positioning precision < 20 cm, velocity accuracy < 3 mm/s, attitude accuracy < 0.2 deg, data output rate of at least 1 Hz, a delay in the real-time output of 0.5 s, and a maximum bandwidth of 50 Kbps. In this sense, the preliminary tests in static mode have provided the possibility to choose the appropriate corrections for future use in real time in real scenarios. Following the strategy of using low-cost components, the tests with the GNSS simulator have allowed the selection and validation of the lowest-cost receiver suitable for the application. Increasing the difficulty and complexity, tests have been carried out in the motion simulator with real wave movements to validate the developed system at the laboratory level. Finally, once the correct functioning of the smart sensor has been verified, tests have been carried out in a real environment. First, in a controlled environment (the port) to verify, on the one hand, the correct integration and operation of the different parts of the smart sensor and, on the other, between the different nodes (two in this case) and the concentrator. Later, its correct behavior in the open deep sea has been verified by installing it on a buoy. In all of them, satisfactory results have been obtained, determining the position (both in real time and in post-processing) with precisions below 20 cm, the principal objective of this development, which will help the other tools (mainly the digital twin) to optimize the performance of these platforms and substantially reduce their costs of production and maintenance. Analyzing several parameters that affect directly or indirectly the behavior of the sensor, such as all HW components used (separately and as a whole system), the algorithms, the environment (multipath and interference), the corrections, and all those that can interfere with the accuracy of the measurement, it was possible to design a GNSS system monitoring with very low cost and high performance. Finally, it should be noted that although the designed prototype corresponds to low technology readiness levels, it has  
Figure 18: Error in east, north, and up components. shown great robustness and reliability. By improving some features such as convergence time and point solution losses, it can be taken to higher levels and provide a very safe and low-cost commercial alternative. Conceptualization, N.R.C., I.L. and A.A.G. ; methodology, N.R.C., I.L. and A.A.G. ; software, N.R.C., I.L. and A.A.G. ; validation, N.R.C., I.L., A.A.G. and A.P.N. ; formal analysis, A.P.N. ; investigation, N.R.C., I.L. and A.A.G. ; resources, A.P.N., L.G.P. and A.C.G.-M.; data curation, N.R.C., I.L. and A.A.G. ; writing--original draft preparation, N.R.C., I.L. and A.A.G. ; writing--review and editing, A.P.N., L.G.P. and A.C.G.-M.; supervision, A.P.N., L.G.P. and A.C.G.-M.; project administration, A.P.N. ; funding acquisition, A.P.N., L.G.P. and A.C.G.-M. All authors have read and agreed to the published version of the manuscript. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 851703.