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Precise point positioning is a global navigation satellite system positioning technique that determines the absolute coordinates of a single receiver using precise satellite orbit and clock products, rather than differencing measurements between a rover receiver and a nearby base station. The method processes pseudorange and carrier-phase observations from a single receiver with externally provided precise satellite ephemerides and satellite clock corrections, eliminating the need for simultaneous reference-station data and enabling standalone decimeter-to-centimeter level positioning ^[1]. The model corrects for or estimates a comprehensive set of error sources: satellite antenna phase center offsets, tropospheric delay, ionospheric delay either through dual-frequency ionosphere-free combination or by estimation, carrier-phase integer ambiguity resolution through uncalibrated phase delays, and receiver clock offset estimated as a free parameter. The solution typically converges over 20 to 30 minutes to centimeter-level accuracy when using undifferenced carrier-phase data, and rapid-convergence techniques accelerate this by estimating wide-lane and narrow-lane ambiguities separately or by applying ambiguity resolution processing strategies. The method is distinct from differential GNSS in that it provides absolute rather than relative positioning and does not require a local reference station, though it depends on high-rate precise satellite clock products ^[2]. The mathematical formulation uses the ionosphere-free combination of dual-frequency carrier phases and pseudoranges, and the position, receiver clock, and zenith tropospheric delay are estimated as unknown parameters in a least-squares or Kalman filter framework ^[3].