GNSS Carrier Ambiguity Resolution Using Multiple Fixing Strategies
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Solution Overview
Problem
Existing GNSS positioning techniques face challenges in accurately resolving carrier-phase ambiguities, which are essential for achieving high precision, particularly in environments with multipath interference and ionospheric errors.
Innovation Solution
A method involving multiple estimators and ambiguity resolution units that apply different strategies to fix carrier range ambiguities, including individual and combined ambiguities, to enhance ambiguity resolution and improve positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If carrier-phase measurements are used to achieve high positioning accuracy, then measurement precision is improved, but the inherent ambiguity in carrier phase measurements makes it difficult to uniquely determine the ranging measurement
Solution Approach 1:
The patent divides the ambiguity resolution process into multiple independent strategies (first ambiguity resolution strategy and second ambiguity resolution strategy) that can be applied separately to different sets of carrier phase measurements. Each strategy processes ambiguities independently, allowing the system to segment the complex ambiguity resolution task into manageable parts and select the most effective approach for each specific measurement set.
Solution Approach 2:
The patent changes the parameter representation by transforming carrier phase measurements into multiple different parameter spaces through different ambiguity resolution strategies. Some strategies may fix individual ambiguities while others fix combinations of ambiguities, effectively changing how the ambiguity parameters are constrained and interpreted to achieve unique solutions.
2Reliability
If multiple ambiguity fixing strategies are applied to resolve carrier range ambiguities, then positioning reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements a dynamic selection mechanism that adapts which ambiguity resolution strategy to apply based on the specific characteristics of the carrier phase measurements and positioning context. The system dynamically switches between different resolution strategies rather than rigidly following a single approach, allowing optimal performance while managing complexity through context-aware decision making.
Solution Approach 2:
The patent applies partial ambiguity resolution by selectively fixing only the necessary ambiguities rather than attempting to resolve all ambiguities simultaneously. This partial action approach reduces processing complexity by focusing computational resources on the most critical ambiguity resolution tasks needed for the current positioning objective.
3Manufacturing precision
If individual carrier range ambiguities are fixed to achieve precise position solutions, then manufacturing precision is improved, but the complexity of processing increases
Solution Approach 1:
The patent merges multiple ambiguity fixing strategies into a unified processing framework where different resolution approaches can be combined and integrated. By merging the results from multiple strategies through a common selection and fusion mechanism, the system achieves high precision position solutions while managing processing complexity through consolidation rather than treating each strategy as a separate independent system.
Data Source
AI summary
A method and apparatus are provided for calculating a position based on Global Navigation Satellite Systems (GNSS) signals. The method includes estimating a first state vector comprising a first set of float carrier range ambiguities using a first estimator, basedon first observations of the GNSS signals; and estimating a second state vector comprising a second set of float carrier range ambiguities using a second estimator, based on second observations of the GNSS signals. It further comprises fixing one or more first carrier range ambiguities, using a first strategy, based on the first set of float carrier range ambiguities; and fixing one or more second carrier range ambiguities, using a second strategy, based on the second set of float carrier range ambiguities. The first strategy for fixing the one or more first carrier range ambiguities is different from the second strategy for fixing the one or more second carrier range ambiguities. The method further includes: selecting a set of fixed carrier range ambiguities from among a plurality of different sets of fixed carrier range ambiguities, the plurality including at least the one or more fixed first carrier range ambiguities and the one or more fixed second carrier range ambiguities; and estimating the position based on the selected set of fixed carrier range ambiguities.