Satellite Navigation Message Parameter Repurposing for Data Expansion
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Solution Overview
Problem
The Galileo satellite navigation system has limited capacity for future expansions and additional information transmission due to reserved bits in its navigation messages, restricting the introduction of new services without significant changes to the basic message structure.
Innovation Solution
Replace one or more parameters of the navigation message, particularly the least significant digits of orbital parameters, with additional information to transmit new data without altering the fundamental message structure, allowing for more frequent updates and maintaining orbital data integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If additional information is transmitted by adding new fields or expanding message structure, then information capacity is improved, but message structure complexity and specification changes increase
Solution Approach 1:
The patent changes the interpretation of existing message parameters by replacing least significant bits of orbital parameters with additional information fields. This allows new data to be transmitted without modifying the message structure, as the same parameter fields are reused with altered content interpretation.
Solution Approach 2:
The patent makes existing parameter fields serve multiple functions: they continue to represent orbital parameters for legacy receivers while simultaneously encoding additional information for advanced receivers. This multi-functionality increases information capacity without adding structural complexity.
2Loss of information
If least significant bits of orbital parameters are replaced with additional information, then information capacity is improved, but orbital parameter accuracy deteriorates
Solution Approach 1:
The patent applies different quality requirements to different parts of the parameter fields. Most significant bits maintain high precision for orbital determination, while least significant bits are repurposed for additional information. This local differentiation allows accuracy preservation where needed while enabling information expansion where tolerance exists.
Solution Approach 2:
The patent uses least significant bits as an intermediary layer that can carry additional information without fundamentally affecting the primary orbital parameter function. These bits act as a buffer zone where information can be encoded with minimal impact on measurement precision.
3Adaptability or versatility
If navigation message parameters are modified to include additional information, then adaptability for new services is improved, but compatibility with existing receivers deteriorates
Solution Approach 1:
The patent inverts the traditional approach by not adding new fields for additional information, but rather encoding them within existing fields. This inversion allows legacy receivers to ignore the modified least significant bits and continue functioning, while advanced receivers can decode the additional information from the same fields.
Solution Approach 2:
The patent creates a dynamic interpretation system where parameter meaning adapts based on receiver capability. Advanced receivers interpret modified parameters to extract additional information, while legacy receivers treat them as standard orbital parameters. This dynamic approach enables forward compatibility without breaking backward compatibility.
Data Source
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AI summary
The invention relates to a method for transmitting additional data along with navigation messages in a satellite navigation system, a navigation message containing one or more parameters. Said method comprises the following steps: at least one parameter of a navigation message is selected for transmitting the additional data (S10); the at least one selected parameter is replaced at least in part by the additional data (S12); and the navigation message that has been modified in this way is transmitted (S14).