AIS Transceiver Validates Ground Station Messages

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Solution Overview

Problem

Satellite-based AIS monitoring systems face interference and inaccurate ship detection due to overlapping AIS radio signals from multiple cells, especially in heavily frequented sea areas, and the automatic switch-off function can be misused by malicious entities to prevent ship monitoring.

Innovation Solution

An AIS ship transceiver with a control unit connected to a database of valid AIS ground stations, which validates received messages to ensure legitimate deactivation or activation of AIS radio signals, preventing misuse and ensuring secure satellite-based monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If satellite-based AIS monitoring is implemented to achieve global coverage, then monitoring coverage is improved, but signal interference and detection accuracy deteriorate due to overlapping signals from multiple cells

Engineering Contradiction:
Improvemonitoring coverageVSAvoidship detection accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent segments the AIS monitoring system into multiple independent ground stations, each managing its own radio cell. Instead of one satellite receiving signals from all cells simultaneously, the system divides the coverage area into discrete segments (cells) with dedicated ground stations, eliminating signal overlap while maintaining global coverage through coordinated segmentation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces ground stations as intermediary components between ships and the central monitoring system. These ground stations act as mediators that receive AIS signals from ships in their respective cells, validate them locally, and forward processed data to the central system, thereby preventing direct signal interference that would occur with satellite-only reception.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If automatic switch-off function is implemented to prevent signal interference in coastal areas, then signal interference is reduced, but security deteriorates due to potential misuse by malicious entities

Engineering Contradiction:
Improvesignal interferenceVSAvoidsystem security
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where ground stations continuously verify ship positions and AIS message authenticity against expected parameters. The system provides feedback loops that validate deactivation requests, compare current cell occupancy with historical data, and alert anomalies, preventing malicious switch-off attempts while maintaining automatic interference prevention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary validation of ground station identities and ship positions before allowing automatic switch-off operations. By pre-verifying the authenticity of deactivation requests and checking whether ships are actually in coastal areas, the system prevents malicious entities from exploiting the automatic switch-off function while still enabling legitimate interference prevention.

Inventive Principle:
Principle #10Preliminary action

3Duration of action of stationary object

If AIS radio signals are transmitted continuously for satellite monitoring, then monitoring continuity is improved, but energy consumption increases

Engineering Contradiction:
Improvemonitoring continuityVSAvoidenergy consumption
Core Design Contradiction:
Duration of action of stationary objectVSUse of energy by stationary object

Solution Approach 1:

The patent implements periodic transmission of AIS radio signals by ground stations instead of continuous transmission. Ground stations transmit reference signals and validation data at regular intervals, allowing ships to maintain monitoring functionality while reducing energy consumption. The periodic action maintains monitoring continuity through scheduled updates rather than constant signal emission.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2728920B1AIS marine transceiver detects a rogue base station
Publication Date: 2018.12.19 DEUTSCHES ZENTRUM FÜR LUFT UND RAUMFAHRT E V
  • EP2728920B1 patent drawingFigure 1

AI summary

The transceiver (1) has a transmitter unit (2) for transmitting the AIS radio signals (AIS1-AIS2,AIS3-AIS4) in response to the message (Message4) received in AIS ground station (12). A receiving unit (3) receives the AIS-radio signals (AIS1-AIS2) of adjacent ships (10) and message of stations. A database (7) stores the data relating to a valid station. A control unit (4) validates the signals according to message of stations as a function of message and stored data, and emits a portion of the signals as a function of validation to deactivate and activate the station. An independent claim is included for a method for transmitting and receiving AIS radio signals.