Dual-Frequency GNSS Signal De-noising via Counter-Rotation Phasor
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Solution Overview
Problem
GNSS signal observations are plagued by noise introduced during signal transmission, affecting accuracy in navigation and other applications, as existing methods fail to effectively mitigate noise across dual-frequency signals.
Innovation Solution
A method and system that utilize a GNSS receiver to downconvert and process dual-frequency signals, cross-correlate and accumulate samples, determine phase, construct a counter-rotation phasor, and apply a low-pass filter to remove noise from one signal using the other, leveraging the differences in noise susceptibility between L1 and L2 frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dual-frequency GNSS signals are used for observation, then positioning accuracy and meteorological data quality are improved, but noise in the signals increases due to ionospheric and atmospheric effects
Solution Approach 1:
The patent extracts and removes noise components from GNSS signals by processing dual-frequency observations separately. The system identifies and eliminates noise introduced by ionospheric and atmospheric effects, retaining only the useful signal components for positioning and meteorological calculations.
Solution Approach 2:
The patent changes the frequency parameter by utilizing dual-frequency (L1 and L2) GNSS signals. By processing observations at different frequencies and applying frequency-dependent corrections, the system compensates for ionospheric delays and reduces noise, thereby improving measurement precision.
2Reliability
If signal processing complexity is increased to remove noise, then signal-to-noise ratio is improved, but device complexity increases
Solution Approach 1:
The patent segments the signal processing into distinct stages: initial noise identification, frequency-dependent correction application, and final signal reconstruction. By dividing the processing into modular steps, the system achieves effective noise reduction while maintaining manageable device complexity.
Solution Approach 2:
The patent introduces intermediary processing steps that act as mediators between the raw dual-frequency signals and the final positioned output. These intermediary corrections for ionospheric and atmospheric effects serve as intermediate transformations that reduce noise without requiring overly complex end-to-end processing.
Data Source
AI summary
Certain implementations of the disclosed technology may include systems and methods for reducing noise in dual-frequency GNSS signal observation. The method can include: receiving, at a GNSS receiver, a first signal and a second signal. At least the second signal includes noise. The first signal is characterized by a first carrier frequency, and the second signal is characterized by a second carrier frequency. The method includes: down converting, sampling, cross-correlating, accumulating, determining ambiguous instantaneous phases, determining non-ambiguous instantaneous phases, producing normalized non-ambiguous instantaneous first phase samples, constructing a normalized first counter rotation phasor, generating a counter-rotated second observable, applying a low pass filter to remove noise; and outputting the filtered second observable.