GNSS Anti-Jammer Interference Cancellation
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Solution Overview
Problem
GNSS navigation systems face integrity, accuracy, and performance threats due to GNSS jamming activities, where interfering signals from non-satellite sources overpower authentic GNSS signals, causing signal saturation and data loss in receivers.
Innovation Solution
A system and method for GNSS anti-jamming using interference cancellation, which includes an antenna, a GNSS anti-jammer with an interference isolator to extract and subtract strong interference signals from received signals, and a local noise remover to digitally remove noise, ensuring the GNSS receiver receives signals without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the GNSS receiver directly processes received signals without interference cancellation, then the system structure remains simple, but the receiver experiences signal saturation and loss of navigation data due to strong interfering signals
Solution Approach 1:
The signal processing system is segmented into distinct functional modules: an interference isolator that extracts strong interfering signals from the composite received signal, and a local noise remover that processes the isolated interference to generate accurate cancellation signals. This segmentation allows each module to specialize in specific signal processing tasks, improving overall reliability while managing complexity through functional decomposition
Solution Approach 2:
The interference isolator acts as an intermediary component between the antenna and the GNSS receiver. It extracts the strong interfering signal portion from the composite signal and provides it to the local noise remover, which then generates accurate cancellation signals. This intermediary structure prevents the interfering signals from directly saturating the GNSS receiver, thereby protecting the navigation data integrity
2Measurement precision
If traditional digital signal processing is used to remove interfering signals, then the receiver structure remains relatively simple, but the processing occurs after signal saturation has already damaged the navigation data
Solution Approach 1:
The interference cancellation process is performed preliminarily in the analog domain before the signals are processed by the GNSS receiver. The interference isolator extracts the interfering signal and the local noise remover generates accurate cancellation signals before the main receiver processes the navigation data. This preliminary action prevents signal saturation from occurring in the first place, ensuring measurement precision is maintained throughout the processing chain
Solution Approach 2:
The patent replaces traditional digital signal processing methods with an analog-domain interference cancellation system. Instead of using digital algorithms to remove interfering signals after reception, the system uses analog circuitry (interference isolator and local noise remover) to cancel interfering signals before they can saturate the receiver. This substitution allows for more precise signal measurement by addressing interference at the analog level where it has not yet corrupted the navigation data
3Measurement precision
If the system uses accurate interference cancellation, then the navigation solution accuracy is maintained, but the system requires complex processing to remove noise generated by the interference isolator
Solution Approach 1:
The local noise remover uses feedback from the interference isolator to accurately characterize the interfering signal properties. By continuously monitoring the isolated interference signal and adjusting the cancellation process accordingly, the system can remove noise generated by the interference isolator itself. This feedback mechanism ensures that the cancellation process does not introduce additional errors, maintaining navigation solution accuracy while managing the complexity of noise removal
Data Source
AI summary
Systems and methods for GNSS anti-jamming using interference cancellation are described herein. In certain embodiments, a system includes an antenna that receives signals, wherein the signals comprise a weak portion associated with one or more GNSS satellites and a strong interference portion from an interfering signal source. The system also includes a GNSS anti-jammer. The GNSS anti-jammer includes an interference isolator that receives the received signals and provides an estimated strong interference portion as an output. The GNSS anti-jammer also includes a summer that subtracts the estimated strong interference portion from the received signals to create a summed signal. Further, the GNSS anti-jammer includes a local noise remover that removes noise generated by the interference isolator from the summed signal, wherein the local noise remover is a processor that digitally removes the noise. Further, the system includes a GNSS receiver coupled to receive the summed signal from the processor.