A Novel Clock Parameterization and Its Implications for Precise Point Positioning and Ionosphere Estimation

Area of Science:

• * Geodesy and Satellite Navigation
• * Signal Processing and Data Analysis

Background:

• * International GNSS Service (IGS) precise clock products conventionally use ionosphere-free linear combinations.
• * This convention complicates precise point positioning-real-time kinematic (PPP-RTK) models that do not use this combination, particularly in separating code hardware biases from integer ambiguities.
• * Existing methods face challenges in efficiently resolving these biases within different carrier phase combinations.

Purpose of the Study:

• * To introduce a novel clock parameterization to simplify the separation of hardware biases and integer ambiguities in PPP-RTK.
• * To develop and assess a dual-frequency PPP-RTK model based on this new parameterization for static positioning.
• * To evaluate the model's performance in terms of positioning accuracy, convergence speed, and ambiguity resolution.

Main Methods:

• * Development of a novel clock parameterization for undifferenced measurements in dual-frequency PPP-RTK.
• * Implementation and testing of the derived PPP-RTK model for static positioning scenarios.
• * Application of the parameterization to slant ionosphere estimation using derived equations.

Main Results:

• * The proposed parameterization facilitates the separation of code hardware biases and integer ambiguities.
• * The dual-frequency PPP-RTK model achieved centimeter-level positioning accuracy with nearly instant convergence and over 99% ambiguity resolution success.
• * Slant ionosphere estimation demonstrated agreement within 1-2 TECU with a standard deviation of 3-4 TECU compared to Global Ionospheric Maps (GIM).

Conclusions:

• * The novel clock parameterization significantly enhances PPP-RTK performance, enabling rapid and reliable high-accuracy positioning.
• * The derived model offers a robust solution for static positioning applications requiring precise real-time coordinate determination.
• * The parameterization shows promise for accurate slant ionosphere monitoring and modeling.