Ionosphere-Constrained Triple-Frequency Cycle Slip Fixing Method for the Rapid Re-Initialization of PPP

Area of Science:

• Geodesy and Satellite Navigation
• Signal Processing

Background:

• Precise Point Positioning (PPP) requires continuous carrier phase observations, making it vulnerable to cycle slips.
• Ionospheric delay significantly impacts cycle slip detection and correction, especially during data gaps.

Purpose of the Study:

• To develop a robust method for cycle slip detection and correction in PPP, avoiding re-initialization.
• To leverage GNSS modernization frequency diversity to mitigate ionospheric delay effects.

Main Methods:

• Constructing extra-wide lane (EWL), wide lane (WL), and narrow lane (NL) epoch-differenced linear combinations.
• Utilizing an ionosphere constrain criterion for determining undifferenced cycle slips via cascading ambiguity resolution.

Main Results:

• Cycle slips were correctly fixed even when occurring in all carrier phase observations.
• 3-minute data gaps were successfully merged without compromising high-precision positioning continuity.
• Kinematic experiments demonstrated instantaneous re-initialization capability.

Conclusions:

• The proposed method effectively detects and corrects cycle slips, ensuring uninterrupted PPP.
• GNSS frequency diversity is crucial for mitigating ionospheric effects in precise positioning.
• Instantaneous re-initialization is achievable, enhancing PPP robustness and reliability.