## 3 Results
### Tests in Static Mode  
For the static test, the smart sensor was placed on several occasions (to cover different configurations and sky conditions) inside the radome and arranged to use multi-constellation and multi-frequency configurations to compute the real-time PPP solution. First, once the smart sensor was mounted, measurements with post-processing techniques (using the PPP technique and MGEX and IGU precise products), keeping the antenna static, with different precise products (International GNSS Service ultra-rapid products, IGU and multi-GNSS-exchange (MGEX) format) were carried out to determine which one provides the better solution with the selected hardware (HW) components. These tests were useful also to characterize the customized algorithm in terms of convergence time and accuracy. Figure 9 presents a fragment of the obtained results in kinematic (receiver and antenna in fixed position but processing the results in movement) and static (keeping the antenna in a fixed position) modes with both precise products in east, north, and up (ENU) components. In the X axis, the time is presented in epochs and each square (3600 epochs) corresponds to 1 h.  
Figure 8: Smart sensor installation on the marking buoy.  
It can be noted that the convergence time with the MGEX precise products is around 30 min and 1 h in static and kinematic modes, respectively, and that the accuracy was kept below \(\pm\)20 cm in both cases. With IGU's precise products by their side, the achieved convergence time in static mode has risen to almost 1 h, whilst in kinematic mode this time has exceeded 4 h. On the other hand, the acquired accuracy in static mode was similar to the previous one. However, in kinematic mode, in the east and north component, the requirement to keep the error below \(\pm\)20 cm was fulfilled; nevertheless, in the up component and after the convergence period, the error exceeds the allowed. Therefore, it can be concluded that the quality and the type of products for clocks and orbits influence the results.  
As a second set of tests in this case, PPP real-time solutions were computed with different real-time corrections to analyze their impact on the quality of the results. These real-time corrections are provided by several NTRIP broadcaster providers, and the precise orbits and clocks needed by the algorithm can be derived from them with periodicity of 60 s and 10 s, respectively. Figure 10 shows in ENU components, a capture comparing  
Figure 9: Post-processing results using (**a**) MGEX and (**b**) IGU precise products.  
four different real-time corrections (SSRA00 WHU0, SSRA00 CAS0, SSRA00 CNE0, and SSRA00 BKG0).  
As can be clearly seen, the quality and continuous availability of these corrections impact directly on the final solution. For instance, the corrections SSRA00 CNE0 and SSRA00 BKG0 present the worst results, with high discontinuity jumps around the 4 th and 5 th hour, while the other two show more stability, keeping throughout the measurement time the error below the specified. These worst results could be due to the type of receiver and antenna used or the quality of the signal and, also, due to multipath or problems when receiving the signal.