PPP: Perhaps the natural processing mode for precise GNSS PNT

Until recently, GNSS PNT accuracy had a bimodal existence: meter-level positioning performance for almost all users, and decimeter- to centimeter-level positioning performance for a small class of high-performance (or professional) users. The recent introduction of mass-market, dual-frequency, multi-constellation GNSS chips and antennas has blurred this distinction. The PPP GNSS measurement processing mode promises to further reduce the gap between high-performance and mass-market GNSS solutions for emerging applications in automotive, cellular, drone, IoT, etc. applications. This work summarizes the current usage of PPP augmentation and its limitations. The latest in GNSS PPP geodetic-quality performance is presented and contrasted with mass-market hardware performance. The benefit of atmospheric constraining is explored. PPP multi-sensor integration, including with network RTK is assessed. All of these developments are leading to the reduction of current PPP limitations, the introduction of new constellation-based services, and, potentially, the near-term use of PPP augmentation at the core of precise GNSS PNT for a wide breath of applications.