Ranging Signal Pulse Phase Encoding for Anti-Spoofing

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Solution Overview

Problem

Existing navigation systems, such as GPS, are vulnerable to jamming and spoofing attacks, leading to a need for a reliable backup or replacement system that provides access control, supports different PNT service levels, increases data transfer rates, and enhances immunity to interference.

Innovation Solution

The proposed solution involves encoding data in the phases of pulses within a pulse group, using inter-pulse intervals to identify specific transmitters, and implementing dithering schedules to limit accurate use of ranging signals. This includes chain-level and transmitter-level dithering, as well as masking dithering, to enhance security and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If GPS systems are used for navigation, then positioning capability is provided, but vulnerability to jamming and spoofing attacks increases

Engineering Contradiction:

Improvenavigation system reliabilityVSAvoidjamming and spoofing attacks

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The navigation signal is segmented into multiple pulse groups with distinct structures. Each pulse group contains ranging pulses with specific phases and intervals that encode transmitter identification. This segmentation allows receivers to distinguish between legitimate signals and jamming attempts by verifying the structured pattern of pulses, thereby improving reliability while maintaining vulnerability resistance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system implements preliminary anti-action by encoding authentication information directly into the signal structure before transmission. Transmitters use specific inter-pulse intervals and phase patterns that serve as pre-established authentication markers. Receivers can preemptively verify these markers to reject spoofing attempts before they can corrupt navigation data, thus improving reliability without increasing vulnerability.

Inventive Principle:

Principle #9Preliminary anti-action

2Reliability

If data is encoded in pulse phases with dithering schedules, then security and access control are improved, but signal processing complexity increases

Engineering Contradiction:

Improveaccess control and securityVSAvoidsignal processing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Dithering schedules and authentication patterns are pre-computed and stored in both transmitters and receivers before operation. The pseudo-random phase variations are generated from pre-shared keys and algorithms, eliminating the need for complex real-time computation during signal processing. This preliminary preparation maintains security while reducing operational complexity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses identical dithering algorithms and authentication protocols implemented in both transmitters and receivers. By copying the same cryptographic functions and signal generation methods across all system components, the receiver can efficiently verify authenticity without requiring more complex processing than the transmitter uses to generate signals, thus balancing security with processing simplicity.

Inventive Principle:

Principle #26Copying

3Productivity

If multiple pulse groups are used for ranging and data transfer, then data transfer rate increases, but signal structure complexity increases

Engineering Contradiction:

Improvedata transfer rateVSAvoidsignal structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The pulse group structure is designed to serve multiple functions simultaneously: ranging pulses provide distance measurement, while the same pulse sequences encode data through phase and timing variations. Inter-pulse intervals carry both timing information for ranging and encoded data bits. This multi-functionality increases data transfer rate without requiring separate dedicated structures for each function, thus limiting complexity growth.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system merges ranging and data communication functions into a unified pulse transmission scheme. Data bits are encoded by modifying the phase and timing of ranging pulses rather than using separate communication channels. This consolidation allows the same signal structure to achieve both positioning and high-rate data transfer, improving productivity while avoiding the complexity of multiple independent systems.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12210108B2Reception of signals for ranging, timing, and data transfer

Publication Date: 2025.01.28 MICROCHIP TECHNOLOGY INC

AI summary

A device is disclosed. In one or more examples, the device may include an antenna to receive a signal encoding timing information for one or more of positioning, navigation, and timing. The signal may include a pulse group comprising a number of ranging pulses and a number of data pulses subsequent to the number of ranging pulses. Respective ones of the number of data pulses may have a phase of either a positive-going phase or a negative-going phase. Data may be encoded using the either positive-going phases or negative-going phases of the data pulses. The device may include a processor to decode the data at least partially responsive to the phases of the respective ones of the number of data pulses.