GNSS Spoofing Jammer Detection via Array Antenna Direction of Arrival
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Solution Overview
Problem
GNSS signals are vulnerable to spoofing jammers that transmit bogus signals, leading to unacceptable errors in position receivers, and existing methods are inadequate for detecting and locating these threats effectively.
Innovation Solution
A method and device using an array antenna with N elements and front-end circuitry to receive and process GNSS signals, determining the direction of arrival of signals using a steering vector, and locating spoofing jammers through code synchronization, allowing for the detection and identification of spoofing jammers by comparing signal elevations and azimuths with Almanac data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional single-antenna receivers are used, then device complexity is low, but the ability to detect and locate spoofing jammers is insufficient
Solution Approach 1:
The patent divides the antenna system into multiple elements (at least two antenna elements) arranged in a specific geometry. Each antenna element independently receives signals, and the signals are then processed separately before being combined. This segmentation enables the system to determine direction of arrival by comparing phase differences between elements, thereby improving spoofing detection capability while maintaining manageable system complexity through modular architecture.
2Measurement precision
If signal processing complexity is increased to accurately determine direction of arrival, then measurement precision improves, but processing time increases
Solution Approach 1:
The patent pre-calculates and stores steering vectors for various direction of arrival angles before actual signal reception. When a signal is received, the system directly uses these pre-computed steering vectors to determine direction of arrival by comparing the received signal with the pre-stored vectors. This preliminary action eliminates the need for complex real-time calculations, thereby improving processing speed while maintaining measurement precision.
3Reliability
If multiple antenna elements are used to detect spoofing jammers, then spoofing detection capability improves, but device complexity increases
Solution Approach 1:
The patent designs the multiple antenna elements and signal processing system to serve multiple functions: (1) receiving authentic GNSS signals, (2) detecting spoofing jammers through direction of arrival analysis, and (3) locating jammers by comparing measured directions with satellite ephemeris data. This multi-functionality approach improves anti-spoofing reliability without proportionally increasing system complexity, as the same hardware infrastructure supports multiple operational modes.
Solution Approach 2:
The patent creates a virtual model of the expected authentic signal geometry using satellite ephemeris data and compares it with the actual measured direction of arrival. By copying the known satellite positions and signal propagation characteristics into a reference model, the system can identify spoofing attempts without requiring additional physical infrastructure, thereby improving reliability while controlling complexity.
4Measurement precision
If the system processes signals from all antenna elements separately, then measurement precision improves, but computational load increases
Solution Approach 1:
The patent combines the signals from multiple antenna elements in the beamforming process, using pre-calculated beamforming weights to coherently sum the signals. By merging the processing of multiple antenna elements into a unified beamforming operation rather than separately processing each element, the system maintains measurement precision for direction determination while significantly reducing computational energy consumption through efficient signal combination techniques.
Data Source
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AI summary
The invention relates to a method for detecting a spoofing jammer for GNSS signals, wherein GNSS signals being available at a receiving position are known and the method comprises the following acts: receiving radio signals from a GNSS by means of an array antenna (10) with N antenna elements and front end circuitry (12, 14) forming N receiver chains, each outputting digital data of the received radio signals, coarsely acquiring (16, 18) GNSS signals contained in the received radio signals by processing the outputted digital data with a receiver reference signal, determining (20, 22, 24, 26) a measure of the direction of arrival for each acquired GNSS signal by means of a steering vector evaluated for each elevation and azimuth in order to cover the hemisphere, and detecting (20, 22, 24, 26) a spoofing jammer from the determined measure of the direction of arrival.