What is PPP-RTK?

PPP-RTK is a hybrid GNSS correction technique that combines the global coverage and flexibility of Precise Point Positioning (PPP) with the rapid convergence and centimeter-level accuracy of Real-Time Kinematic (RTK) methods. Standard PPP uses precise satellite orbit and clock corrections, typically derived from a global network, to enable a single GNSS receiver to achieve decimeter to centimeter-level accuracy anywhere in the world. However, PPP alone often suffers from long convergence times, sometimes 30 minutes or more, before high accuracy is achieved.

PPP-RTK addresses this limitation by supplementing PPP corrections with additional real-time information from a regional network of reference stations, such as atmospheric (ionospheric and tropospheric) corrections and satellite phase biases. This enables rapid ambiguity resolution, allowing the receiver to fix carrier phase ambiguities as integers, which is key to achieving fast, reliable centimeter-level positioning. 

Unlike traditional RTK, which requires a dense local network and is limited by baseline distance, PPP-RTK can deliver high accuracy over much larger areas, even hundreds or thousands of kilometers from the nearest reference station, making it ideal for applications like autonomous vehicles, precision agriculture, and surveying in remote regions. The technique is also known as “network PPP with integer ambiguity resolution” and is supported by modern GNSS augmentation services and standards such as RTCM State Space Representation (SSR) messages.