Radionavigation Signal Processing Using Coherent Widelane Ambiguities
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Solution Overview
Problem
Current satellite positioning systems face challenges in achieving precise positioning due to phase measurement ambiguities, which are not fully resolved by existing differentiation techniques, leading to limitations in accuracy and sensitivity to noise and multipath effects.
Innovation Solution
A method for processing radionavigation signals that determines coherent widelane ambiguities using a GNSS receiver, combining code and phase measurements from multiple frequency bands to calculate pseudo distances, thereby overcoming ambiguity issues and reducing noise sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase measurements are used to improve positioning precision, then measurement accuracy improves to millimeter level, but integer ambiguities remain unresolved making measurements ambiguous
Solution Approach 1:
The patent segments the phase measurement problem into two parts: the fractional part (which is directly measurable with high precision) and the integer part (the ambiguity). By using widelane combinations and reference systems, the integer ambiguity is resolved separately, allowing both parts to be processed independently and then combined for complete positioning information.
Solution Approach 2:
The patent introduces widelane combinations as an intermediary mechanism. These combinations create new observables that have longer wavelengths, making the integer ambiguities easier to resolve. The widelane combinations act as a bridge between the ambiguous narrow-lane phase measurements and the unambiguous positioning solution.
2Reliability
If differentiation techniques are applied to resolve phase ambiguities, then common errors are eliminated, but the basic phase ambiguities cannot be traced
Solution Approach 1:
The patent applies preliminary action by resolving the integer ambiguities before final positioning calculation. Reference systems pre-determine the widelane ambiguity values, and these resolved ambiguities are then used in the positioning computation. This preliminary resolution of ambiguities preserves the complete information needed for accurate positioning while still eliminating common errors through the differentiation process.
3Loss of information
If code measurements are used instead of phase measurements, then ambiguity is avoided, but positioning accuracy degrades to meter level
Solution Approach 1:
The patent merges code measurements and phase measurements into a unified processing framework. Code measurements provide unambiguous range information, while phase measurements provide high-precision fractional information. By combining these measurements and resolving the phase ambiguities through widelane combinations and reference systems, the patent achieves both unambiguity and high precision simultaneously.
Data Source
AI summary
A method for processing radionavigation signals coming from satellites that broadcast the radionavigation signals on at least two distinct frequencies, comprisesreceiving the signals for each satellite,realizing, for each satellite, non-differentiated measurements of code and phase (10),determining the widelane ambiguities in a coherent manner on the group of satellites (12, 13, 14) by using the widelane biases associated with the satellites, received from a reference system, andglobal positioning of the receiver with the help of measurements of code and phase and the coherent widelane ambiguities (16, 18).The global positioning comprises, for each satellite, the determination (16) of a pseudo distance by means of an ionosphere-free combination of the measurements of code and of the difference of the phase measurements, compensated for the widelane ambiguity, this ionosphere-free combination being optimized in terms of noise. The pseudo distance is determined by receiving the satellite clock values associated with the ionosphere-free combination from the reference system.