GNSS Interference Cancellation to Prevent Receiver Saturation
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Solution Overview
Problem
GNSS navigation systems are vulnerable to jamming interference, which can saturate amplifiers and ADCs, leading to data loss and compromised navigation accuracy.
Innovation Solution
Implementing a system that cancels interfering signals in the analog domain by isolating and subtracting them from received signals using a GNSS anti-jammer and interference isolator, followed by noise removal in the digital domain to provide clean GNSS signals to the receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GNSS receiver processes strong interfering signals, then the receiver can operate in jammed environments, but the dynamic range is exceeded causing saturation and data loss
Solution Approach 1:
The received signal is segmented into two separate components: a strong interfering signal portion and a weak GNSS signal portion. This segmentation allows each component to be processed independently through separate signal paths, preventing the strong interference from saturating the main receiver while enabling extraction and cancellation of the interference to recover the weak GNSS signals
Solution Approach 2:
The interfering signal is extracted from the composite received signal using a dedicated interference signal processor that identifies and isolates the strong jamming components. This extracted interference signal is then fed to a canceller that subtracts it from the original received signal, removing the harmful interference while preserving the weak GNSS signals for accurate processing
2Manufacturing precision
If analog domain interference cancellation is implemented, then dynamic range is preserved, but system complexity increases
Solution Approach 1:
An analog summer/c canceller is introduced as an intermediary component in the signal path that performs the interference subtraction in the analog domain before the signals reach the main GNSS receiver. This analog cancellation mechanism preserves the full dynamic range of the receiver by removing strong interferers early in the signal chain, avoiding the need for complex digital signal processing and high-resolution ADCs that would be required to handle saturated inputs
Data Source
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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.