LORAN Pulse Messaging for Higher-Rate Secure PNT

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Solution Overview

Problem

Terrestrial-based Precision Navigation and Timing (PNT) systems, such as eLORAN, face limitations in data rate and susceptibility to interference, particularly in comparison to satellite-based systems like GPS, which can be vulnerable to jamming and spoofing.

Innovation Solution

The implementation of a bi-directional communication system within the PNT system using LORAN stations that transmit LORAN PNT RF pulses with embedded message RF bursts, utilizing quadrature phase shift keying modulation and error correction, to enhance data transmission capacity and security, and include a method for encrypting and routing messages within the existing LORAN bandwidth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If message RF bursts are embedded between LORAN PNT RF pulses, then data rate capacity increases, but system complexity increases

Engineering Contradiction:
Improvedata rate capacityVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines navigation and communication functions into a single LORAN system. Message RF bursts are embedded within the existing LORAN pulse structure, allowing simultaneous transmission of positioning data and communication messages through the same infrastructure, thereby increasing data rate capacity without requiring separate communication hardware.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The LORAN system is enhanced to perform multiple functions: traditional navigation timing via RF pulses and data communication via embedded message bursts. This multi-functionality allows the existing terrestrial PNT infrastructure to provide both positioning services and high-capacity data transmission, addressing the need for improved data rates without building separate systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If quadrature phase shift keying modulation is used for message RF bursts, then data transmission efficiency improves, but susceptibility to interference increases

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidsusceptibility to interference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent employs quadrature phase shift keying (QPSK) modulation, which encodes data in the phase of the carrier signal. This parameter-based modulation scheme achieves high data transmission efficiency by utilizing phase variations rather than amplitude or frequency changes, making the signal more robust against certain types of interference while maintaining high data rates.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If bi-directional communication is implemented, then system versatility improves, but device complexity increases

Engineering Contradiction:
Improvesystem versatilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The bi-directional communication system is segmented into distinct functional components: message embedding generators at transmitting LORAN stations, message reception and processing units at user equipment, and protocol management layers. This segmentation allows complex bi-directional communication capabilities to be built from manageable modular components, reducing overall system complexity while maintaining versatility.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach increases the data rate capacity of the LORAN system, improves position accuracy by enabling more frequent ASF corrections, and provides secure, efficient bi-directional messaging, effectively addressing the limitations of existing terrestrial PNT systems.

Implementation Method 1

a LORAN transmitter (coupled to the LORAN antenna) and configured to transmit a series of LORAN PNT RF pulses

Methodology Applied
Scientific EffectElectromagnetic radiation:

Implementation Method 2

The message embedding generator may be configured to generate the plurality of message RF bursts using quadrature phase shift keying modulation

Methodology Applied
Scientific EffectQuadrature phase shift keying modulation: Phase Modulation

Data Source

PatentEP3734315B1RF PNT system with embedded messaging and related methods
Publication Date: 2024.03.06 EAGLE TECHNOLOGY LLC
  • EP3734315B1 patent drawingFigure 1
  • EP3734315B1 patent drawingFigure 2
  • EP3734315B1 patent drawingFigure 3~4

AI summary

An RF PNT system may include LORAN stations. Each LORAN station may include a LORAN antenna, and a LORAN transmitter coupled to the LORAN antenna and configured to transmit a series of LORAN PNT RF pulses having a time spacing between adjacent LORAN PNT RF pulses. One or more of the LORAN stations may include a message embedding generator coupled to the LORAN transmitter and configured to generate message RF bursts based upon an input message, and with each message RF burst being in the time spacing between respective adjacent LORAN PNT RF pulses.