Triple-Frequency Satellite Bias Estimation for Fast PPP Convergence
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Solution Overview
Problem
Dual-frequency PPP estimation in GNSS systems requires a convergence time of about 10 minutes or longer, making it impractical for real-time applications, and the introduction of third carrier frequencies offers an opportunity for improved accuracy and speed.
Innovation Solution
A method for providing a global satellite correction signal using triple frequency satellite bias determination, involving a reference receiver to measure carrier phases of three frequencies and a precise point positioning module to estimate ambiguities and biases, enabling faster convergence and higher accuracy through the use of triple frequency measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dual-frequency PPP estimation is used to achieve centimeter-level position accuracy, then measurement precision is improved, but convergence time increases to 10 minutes or longer
Solution Approach 1:
The patent transitions from dual-frequency to triple-frequency carrier phase measurements, adding a new dimension (third frequency) to the measurement system. This enables the formation of additional wide-lane combinations (first wide-lane from L1-L2, second wide-lane from L2-L3) that accelerate ambiguity resolution and reduce convergence time while maintaining centimeter-level positioning accuracy
2Productivity
If triple frequency measurements are used to reduce convergence time, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent segments the triple-frequency measurement process into distinct components: first wide-lane ambiguity determination (L1-L2), second wide-lane ambiguity determination (L2-L3), and narrow-lane bias estimation. This segmentation allows each frequency combination to be processed independently through specific linear combinations, managing system complexity while achieving rapid convergence
3Speed
If triple frequency carrier phase measurements are processed to determine multiple wide-lane ambiguities, then convergence speed is improved, but calculation complexity increases
Solution Approach 1:
The patent transforms the triple-frequency carrier phase measurements into different parameter combinations through linear combinations: wide-lane combinations (L1-L2, L2-L3) for rapid ambiguity resolution and narrow-lane combinations for precise bias estimation. This parameter transformation enables fast convergence by processing measurements in optimized forms rather than raw carrier phases
Data Source
AI summary
The precise point positioning module or the estimator is configured to determine second wide-lane (e.g., extra-wide-lane), floating or fixed ambiguities and associated second wide-lane biases for each satellite based on the second carrier phase and third carrier phase associated with the corresponding satellite. The precise point positioning module or the estimator is configured to determine narrow-lane, floating or fixed ambiguities, a satellite slow clock solution and a time-variant narrow-lane bias for a corresponding satellite based within a narrow-lane bias/code-phase bias filter for each satellite. A correction data estimator is configured to provide a correction signal that includes the first wide-lane bias, second wide-lane (e.g., extra-wide-lane) bias, time-variant narrow lane bias, orbit correction, and clock correction for a given satellite.