Ranging Signal Pulse-Phase Encoding for Secure PNT
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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 backup or replacement system that provides secure and reliable positioning, navigation, and timing (PNT) services.
Innovation Solution
The proposed solution involves encoding information indicative of a specific transmitter in a pulse group of a ranging signal, using a pulse-phase-signature schedule, and applying dithering techniques to enhance security and immunity to jamming and spoofing attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If GPS and similar navigation systems are used for positioning, navigation, and timing, then convenience and global coverage are improved, but vulnerability to jamming and spoofing attacks increases
Solution Approach 1:
The navigation system is segmented into multiple independent terrestrial transmitters distributed across different locations. Each transmitter operates autonomously and provides localized PNT services. This segmentation eliminates single-point failure risks and reduces vulnerability to widespread jamming or spoofing attacks, as attackers would need to compromise multiple geographically distributed transmitters simultaneously.
Solution Approach 2:
The patent introduces terrestrial transmitters as intermediary devices between satellites and receivers. These ground-based transmitters receive timing signals from satellite systems and re-broadcast them locally, creating an intermediate layer that provides secure, localized PNT services. This intermediary layer protects against direct satellite signal jamming and spoofing by using ground-based transmission with embedded security features.
2Reliability
If pulse-phase-signature schedules and dithering techniques are applied to transmitter identification, then security and immunity to attacks are improved, but system complexity increases
Solution Approach 1:
The system employs periodic pulse transmissions with predetermined phase relationships and time intervals. Each transmitter broadcasts pulses at regular intervals with specific phase signatures that identify the transmitter. This periodic structure simplifies receiver processing through correlation techniques while maintaining security through unique phase-code combinations that are difficult to replicate without authorization.
Solution Approach 2:
The patent utilizes variations in pulse phase, time interval, and frequency as encoding parameters to create unique transmitter identifiers. By changing these physical parameters in predetermined patterns, the system achieves high security without requiring complex encryption algorithms. The phase-code sequences and dithering patterns modify signal parameters in ways that are easy to generate but difficult to spoof, balancing security with implementation simplicity.
Data Source
AI summary
A method is disclosed. In various examples, the method may include receiving an instruction for generating a ranging signal, and transmitting the ranging signal at least partially responsive to the instruction. In various examples the ranging signal may be transmitted via a terrestrial transmitter for transmitting radio waves having encoded messaging information and timing information for one or more of positioning, navigation and timing. In various examples, the ranging signal may exhibit a first ranging pulse and a second ranging pulse of a pulse group and an encoded transmitter identifier, the transmitter identifier encoded by modulating an inter-pulse interval defined between a start of the first ranging pulse and a start of the second ranging pulse.