PPP-RTK with augmentation from a single reference station

Precise point positioning (PPP) with augmentation by a network of continuously operating reference stations (CORS), known as PPP-RTK, enables fast ambiguity resolution with PPP. However, it suffers from the dependency of a CORS network for augmentation corrections generation. This paper proposes a new real-time PPP-RTK method that generates the augmentation corrections using undifferenced and uncombined PPP at a single reference station. This method enables high accuracy and fast convergence real-time PPP-RTK for both multi-frequency and single-frequency receivers without the need of PPP estimate convergence at the reference station. It provides potential flexibility to include any number of more local reference stations for augmentation correction generation. The method can be regarded as a state-space-representation based RTK approach that offers equivalent performance but can overcome the limitations associated with the observation-space-representation based positioning techniques, such as the high transmission rate and rigorous baseline length requirements. It can also be considered as a special case of the network-based PPP-RTK but it offers increased flexibility in system implementation and opens doors to develop new correction services for PPP-RTK applications. Field tests results validate the positioning performance of the proposed method. The static positioning test indicates that the method could instantly output cm-level positioning solutions even before the corrections estimate convergence at the reference station. And the kinematic vehicle-based test reveals that, the method can provide the rover station receiver cm-level positioning solutions with instant initialization and ambiguity resolution either using a dual-frequency Global Navigation Satellite System (GNSS) receiver or a low-cost single-frequency GNSS receiver with 100% ambiguity fix rate. Also, the test results with different baseline lengths prove that the proposed method will be gradually degraded into standard AR-enabled PPP when the baseline length grows longer, and the ambiguity can be effectively fixed even at the 1258 km baseline length.