Aircraft Navigation System with Dual GPS Receivers for Jamming Detection

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Solution Overview

Problem

Civil aircraft navigation systems are vulnerable to GPS signal jamming and spoofing, which can impair or alter aircraft position data, posing a significant threat to safety, especially in civil airspace where only civil-certified GPS receivers are allowed.

Innovation Solution

An aircraft navigation system comprising both civil-certified and military-type GPS receivers, a monitoring unit, and an alerting unit that detects abnormal navigation conditions such as jamming or spoofing by comparing position data from both receivers, initiating an alert procedure, and switching to military-type GPS receiver data for navigation in emergency situations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If civil-certified GPS receivers are used for navigation in civil airspace, then the aircraft can operate in civil airspace with certified equipment, but the navigation system becomes vulnerable to GPS signal jamming and spoofing

Engineering Contradiction:
Improveability to operate in civil airspaceVSAvoidnavigation security
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The navigation system is segmented into multiple independent GPS receiver components: civil-certified receivers for normal civil airspace operation and military-type receivers for emergency or protected operation. This segmentation allows the system to maintain adaptability to different airspace requirements while improving reliability through redundancy and alternative navigation sources when jamming or spoofing is detected

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A monitoring unit acts as an intermediary between the GPS receivers and the navigation system. This intermediary continuously monitors GPS signal quality, detects jamming or spoofing conditions, and triggers switching to alternative receivers or navigation methods, thereby protecting the navigation system from harmful external interference while maintaining continuous operation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If military-type GPS receivers are used continuously for navigation, then navigation precision and anti-spoofing capability are improved, but the aircraft cannot operate in civil non-segregated airspace due to certification restrictions

Engineering Contradiction:
Improvenavigation securityVSAvoidability to operate in civil airspace
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system dynamically switches between civil-certified and military-type GPS receivers based on operational conditions and airspace requirements. During normal civil airspace operation, the system uses certified civil receivers to maintain adaptability. When emergency conditions arise or in segregated airspace, it switches to military-type receivers for enhanced security, thus achieving both adaptability and reliability through dynamic configuration

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The aircraft is pre-equipped with both civil-certified and military-type GPS receivers before flight, with the military receivers kept in standby or activated only when needed. This preliminary preparation ensures that when civil airspace operation is required, the certified receivers are used, but when security threats or emergency conditions occur, the military receivers are already available for immediate switching, thus resolving the contradiction between certification requirements and security needs

Inventive Principle:
Principle #10Preliminary action

3Reliability

If monitoring and comparison of position data from multiple receivers is implemented, then detection of jamming or spoofing conditions is improved, but device complexity increases

Engineering Contradiction:
Improvedetection capabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The monitoring unit performs multiple functions: it monitors GPS signal quality, compares position data from different receivers, detects jamming or spoofing conditions, and triggers alerting and switching operations. By consolidating these multiple functions into a single multi-functional monitoring unit, the system improves detection capability while minimizing the increase in device complexity that would result from adding separate dedicated components for each function

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

Data Source

PatentEP2871495B1Aircraft navigation system and method of navigating an aircraft
Publication Date: 2020.06.03 AIRBUS DEFENCE & SPACE GMBH
  • EP2871495B1 patent drawingFigure 1

AI summary

An aircraft navigation system and method of navigating an aircraft are proposed. The system (1) comprises a civil-certified GPS-receiver (3) for determining first position information based on C/A-GPS-signals and a military-type GPS-receiver (5) for determining a second position information based on P(Y)-GPS-signals. The system (1) is adapted to issue aircraft navigation signals based on the first position information when the aircraft is flying under normal navigation conditions in civil airspace. A monitoring unit (7) detects a first abnormal navigation condition upon occurrence of jamming conditions within the C/A-GPS-signals. Furthermore, it compares the first position information with the second position information and detects a second abnormal navigation condition upon occurrence of a difference between these position information being larger than a threshold value for more than a threshold duration. Upon detection of an abnormal navigation condition, an alert procedure such as transmitting a warning signal to a pilot is initiated. In a particular application in remotely piloted aircraft, Command & Control link-loss is additionally monitored and in case of link-loss, a transponder code is automatically set to issuing a signal indicating communication failure. Furthermore, when in such situation an abnormal navigation condition is additionally detected, a transponder code is set for issuing a signal indicating airborne emergency and, subsequently, the aircraft navigation system (1) is switched to navigating based on position information from the military-type GPS-receiver (5).