GNSS Receiver Replica Signal Detection via Delay-Doppler Mapping
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Solution Overview
Problem
Existing GNSS receivers face challenges in accurately detecting satellite signal replicas due to multipath and spoofing, especially in urban environments, where errors can result in position inaccuracies of hundreds of meters, and current detection methods are computationally demanding and inadequate for devices with reduced resources.
Innovation Solution
A method involving a GNSS receiver that performs GNSS tracking, generates in-phase and quadrature components, applies coherent accumulation, transforms the signals into the frequency domain, and analyzes bi-dimensional maps of correlation energy distribution to detect anomalies indicative of replica signals, using techniques like neural networks for pattern recognition and classification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If known detection methods (multi-correlation technique, code-loop discriminator) are used to detect multipath interferences, then detection capability is provided, but measurement precision and reliability are inadequate, especially in urban environments where position errors can exceed hundreds of meters
Solution Approach 1:
The patent transitions from one-dimensional code delay domain analysis to two-dimensional delay-Doppler map analysis. By adding the Doppler frequency dimension, the system can better distinguish between legitimate satellite signals and replica signals (multipath/spoofing), significantly improving measurement precision and reliability in challenging urban environments
Solution Approach 2:
The patent implements a nested detection architecture where multiple tracking channels with increased number of correlators are organized into monitor channels. This nested structure allows for hierarchical signal analysis, enhancing both detection capability and robustness against interferences
2Measurement precision
If super-correlation method is used to mitigate spoofing and multipath effects, then position estimation accuracy is improved, but device complexity and computational requirements increase significantly
Solution Approach 1:
The patent extracts only the essential features needed for replica detection by generating delay-Doppler maps and analyzing correlation energy distribution, rather than implementing the full super-correlation method. This selective extraction maintains position estimation accuracy while significantly reducing computational complexity for devices with limited resources
Solution Approach 2:
The patent implements a partial version of the super-correlation method by focusing specifically on the delay-Doppler map generation and analysis aspects, rather than implementing all computationally demanding steps. This partial action provides sufficient accuracy improvement without the full computational burden
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the detection capabilities of satellite signal replicas, improving the accuracy and robustness of position estimation while reducing computational requirements, enabling more reliable GNSS positioning even in challenging environments.
Implementation Method 1
performing a coherent accumulation over a given coherent accumulation period on each of such delayed signals obtaining a coherently accumulated signal
Implementation Method 2
Both multipath and spoofing may be affected by the Doppler effect if the scenario is dynamic, thus, affecting the resulting final position estimated by a GNSS receiver with an additional error component
Data Source
AI summary
A method detects replicas of satellite signals in a GNSS receiver. The satellite signals are transmitted from a plurality of satellites of a constellation of satellites. The method includes navigation processing procedure performed at the GNSS receiver. The method includes receiving at least one of the satellite signals, and for the at least one of the received satellite signals. The method includes dumping in-phase and quadrature components from a correlation procedure of a tracking process of the satellite signals, generating a plurality of delayed signals including the in-phase and quadrature components, and generating a coherently accumulated signal from the delayed signals. The method includes transforming the coherently accumulated signal to a frequency domain signal, generating a bi-dimensional map from the frequency domain signal, and determining whether or not the satellite signals are affected by replicas based on analysis of the bi-dimensional map.