## 4 Precise Point Positioning Results
### CNES Evaluation
The real-time and post-processed products have been used to correct the satellite broadcast ephemeris and clocks, as well as to add code and phase biases to the undifferenced and uncombined measurement model given in Equation (1). The comparison in terms of mean, standard deviation, and 95 percentile of the horizontal errors between the estimated trajectory and the reference is presented in Table 9. When comparing the errors using only the code and phase measurements on one hand and the three types of measurements on the other hand, the accuracy of the position is better when the measures are sampled at 10 Hz rather than at 1 Hz. With the POST products, the mean horizontal position accuracy is improved by 28% and the RMS by 43% or 56% in the Snapshot and full AR modes, respectively, with the 10 Hz Doppler measurement. Conversely, the use of the 1 Hz measurements does not improve the position accuracy in a significative way. It may even worsen the precision. The results obtained with the RT products follow the same pattern. The positioning error standard deviation lies around 2 m because the analysis has been performed over the whole trajectory. However, in a dense urban environment, the accuracy of the solution is very poor, mainly because of the bad geometry of the satellites and the multipath effects in the narrow streets (red part of the trajectory depicted in Figure 13(b)). Keeping only the \"sub-urban\" part of the trajectory (in blue in Figure 13(b)), the mean position accuracy is 0.38 m with code and phase measurements and 0.34 m with code, phase, and Doppler measurements in full AR mode. In the Snapshot mode, the code/carrier phase solution leads to an accuracy of 0.48 m and the full code/carrier phase/Doppler solution enables a positioning accuracy of 0.41 m. In both the AR and Snapshot modes, adding the Doppler measurement increases the horizontal accuracy by around 10%. This means that using the Doppler measurement has a greater impact when the environment is harsh. This result follows the theoretical analysis performed by [32]. Regarding the velocity errors, the same conclusions can be drawn. Taking into account the high-rate Doppler measurement leads to an augmentation of the velocity accuracy, especially in the  
Figure 14: Experimental setting and path traveled during the car campain. (a) Experimental setting. (b) Reference trajectory. In blue the “sub-urban” part, in red the “urban” part. PPP-Snapshot mode, for which a horizontal standard deviation of 13 cm/s can be obtained with 10 Hz code, phase, and Doppler measurements. Table 10 displays the ambiguity fixing rates in the several cases, according to the use of Doppler measurements or not and the measurement rate. Not surprisingly, processing the Doppler measurements does not improve the ambiguity fixing rates in the PPP-Snapshot mode, since the ambiguities are reset at every epoch and thus do not benefit from the Kalman filter convergence effect. However, when it comes to the PPP-AR mode, the extra-widelane and the widelane fixing rates are increased when using the Doppler measurements, but the narrowlane becomes harder to fix with both the POST and RT products.