AIS Message Encoding for Low-Power Satellite Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing Automatic Identification System (AIS) used in e-Navigation faces challenges in detectability, especially when signals from multiple vessels overlap or are transmitted at low power, making it difficult for low earth orbit satellites to receive and decode messages accurately due to noise and interference.
Innovation Solution
The method involves generating e-Navigation messages with enhanced detectability by encoding a binary payload using error protection schemes such as forward error correction, block coding, convolutional coding, and interleaving, and encapsulating it in a message wrapper, which allows for reliable recovery of message data even in the presence of bit errors and channel interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If error protection encoding is applied to e-Navigation messages, then message detectability and reliability are improved, but message complexity and processing overhead increase
Solution Approach 1:
Error protection encoding is applied in advance to the binary payload before message transmission. The encoding process prepares the message with error correction capabilities beforehand, so that even if bit errors occur during transmission, the receiver can reliably detect and correct errors without requiring complex real-time processing.
Solution Approach 2:
The patent applies specific error protection encoding schemes (such as convolutional coding, block coding, or interleaving) that transform the binary payload into a more robust format. These encoding methods change the parameter structure of the message by adding redundancy bits and organizing data in patterns that enable error detection and correction, thereby improving message detectability while maintaining manageable complexity through standardized approaches.
2Use of energy by moving object
If e-Navigation messages are transmitted at low power levels, then energy consumption is reduced, but signal detectability and reception reliability deteriorate
Solution Approach 1:
The patent implements error protection encoding as a cushioning mechanism against signal degradation. By encoding the binary payload with error correction codes before transmission, the system creates a buffer that protects the message content even when received at low power levels with potential bit errors. This allows vessels to transmit at lower power while maintaining reception reliability through the error correction capability built into the message structure.
3Productivity
If multiple vessels transmit simultaneously in congested channels, then channel utilization increases, but signal interference and detection difficulty increase
Solution Approach 1:
The patent converts the harmful effect of potential bit errors from signal interference into a manageable condition through error protection encoding. By incorporating redundancy and error correction codes, the system can tolerate a certain level of interference and bit errors that naturally occur in congested channels with simultaneous transmissions. This allows high channel utilization while maintaining message detectability through the error correction capability that transforms interference-induced errors into correctable conditions.
Data Source
AI summary
Methods and systems for enhancing the detectability of maritime e-Navigation messages are provided. Transmitters apply error protection encoding to the payload portion of messages to be transmitted, which are wrapped in a standard e-Navigation message format such as that used by the Automatic Identification System. Transmitted messages are received by a satellite or other surveillance platform employing a compatible radio frequency receiver to collect message signals over a large area or great distance. Candidate messages are identified and the error protection encoding decoded to recover messages.