Evaluation of decimeter positioning post-processing algorithms using GNSS raw measurements

This paper evaluates the post-processing stages of a global navigation satellite system (GNSS) receiver using the Android datasets. GNSS receivers that are integrated in smartphones are constrained by low size, weight, power consumption, and cost (SWAPC) requirements. These conditions usually difficult the possibility to obtain an accurate position, velocity, and time (PVT) solution. This study evaluates the raw GNSS data of Android smartphones using decimeter positioning algorithms. A python localization toolkit (PLT) is created for these purposes. The toolkit contains four main parts: The reading and synchronization of the raw measurements, the pseudorange corrections module, the positioning algorithms, and the evaluation of the results. In order to achieve decimeter positioning, the pseudorange corrections module performs the transition from the code pseudorange to carrier phase pseudorange using the accumulated delta range in hatch filter. Also, loose coupling (LC) between GNSS and inertial navigation system (INS) can benefit the positioning in case there is no line-of-sight (LOS). The results show that meter instead of decimeter accuracy is achieved in good condition scenarios, even using the accumulated delta range (ADR). Another finding is that the LC outperforms the GNSS positioning algorithms if the GNSS solution has a low horizontal root mean square error.