GNSS Timing Synchronization via Antenna Clock Offset Correction
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Solution Overview
Problem
Global Navigation Satellite Systems (GNSS) are vulnerable to interference such as jamming, meaconing, and spoofing, which can disrupt accurate timing and positioning, posing a threat to critical applications like financial transactions and power grid operations.
Innovation Solution
A time synchronization system that compares satellite signals from multiple satellites to detect and correct interference by using unique parameters like clock offsets, employing directional antennas and distributed processing units to enhance resilience against interference attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS receivers use satellite signals for timing synchronization, then accurate timing is achieved, but the system becomes vulnerable to jamming, meaconing, and spoofing interference
Solution Approach 1:
The patent segments the timing verification process by comparing timestamps from multiple independent satellite signals. Each satellite signal is evaluated separately, and the receiver identifies consistent timestamps across multiple satellites while detecting anomalies in individual signals. This segmentation allows the system to isolate and reject interfered signals while maintaining timing accuracy from authentic signals.
Solution Approach 2:
The patent implements feedback mechanisms where the receiver continuously monitors satellite signal characteristics and adjusts its signal selection based on detected interference patterns. The system provides feedback by comparing expected timestamp patterns with actual received timestamps, identifying deviations caused by meaconing or spoofing, and dynamically adjusting which satellite signals are trusted for timing synchronization.
2Productivity
If the system accepts all GNSS signals as authentic, then signal availability is maintained, but meaconing and spoofing signals cannot be differentiated from legitimate signals
Solution Approach 1:
The patent performs preliminary verification of satellite signal authenticity by analyzing timestamp consistency before using the signals for timing synchronization. The receiver pre-evaluates multiple satellite signals, comparing their timestamps and identifying patterns that indicate meaconing or spoofing. This preliminary action allows the system to maintain high signal availability by accepting authentic signals while preemptively rejecting fraudulent ones.
Solution Approach 2:
The patent changes the evaluation parameter from simply accepting all GNSS signals to verifying timestamp consistency across multiple satellites. By introducing timestamp comparison as a verification parameter, the system can distinguish authentic signals from meaconing and spoofing signals while maintaining availability of legitimate signals for timing synchronization.
3Reliability
If additional clocks and GNSS simulators are used to detect spoofing, then detection capability is improved, but system complexity and cost increase
Solution Approach 1:
The patent enables the GNSS receiver to perform self-verification of signal authenticity using only its existing hardware. The receiver independently compares timestamps from multiple satellite signals and identifies inconsistencies indicating meaconing or spoofing, without requiring external clocks or simulators. This self-service approach maintains spoofing detection capability while avoiding additional hardware complexity.
Data Source
AI summary
A time synchronization system an input interface configured to receive pseudorange measurements from a set of antennas of at least one Global Navigation Satellite System (GNSS) receiving system that operates the antennas at known positions according to a clock with an unknown time bias to receive signals from satellites in sight of the antennas and an output interface configured to output the determined time bias. The time synchronization system also includes a processor configured to compare the pseudorange measurements of different antennas to produce an antenna-specific clock offset for each of the antennas, correct the pseudorange measurements of the antennas according to the antenna-specific clock offsets of corresponding antennas to produce corrected pseudorange measurements, and determine the time bias of the clock using the corrected pseudorange measurements.