Global Instantaneous Centimeter-Level Multi-constellation and Multi-frequency Precise Point Positioning with Cascading Ambiguity Resolution

With the progresses of Global Navigation Satellite System (GNSS), a number of satellites transmitting multi-frequency signals contribute precise point positioning (PPP). Global instantaneous or single-epoch centimeter-level PPP may be reached because global single-epoch narrow-lane (NL) ambiguity resolution (AR) may be possible with many wide-lane (WL) ambiguities being fixed instantaneously, which can improve the accuracy of the instant NL ambiguities. In this article, the cascading AR (CAR) method was extended to the GPS, Galileo, and BDS-3 all-frequency signals. The performance of instantaneous PPP was investigated with global public stations. The results showed that attributed to the additional frequency observations, the instant positioning accuracy improved substantially. On a global scale, the instant horizontal and up positioning accuracy improved from about 20 and 60 cm, respectively, for the dual-frequency PPP-CAR to about 6 and 20 cm, respectively, for the multi-frequency PPP-CARs. These results are quite encouraging for global autonomous driving cars because better positioning accuracy is expected once the multi-constellation and multi-frequency signals are integrated with inertial sensors.