GNSS Continuous Tracking Counter for Low-Bandwidth Satellite Messages
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Solution Overview
Problem
The increasing demand for bandwidth in communication systems for global navigation satellite systems (GNSS) poses a challenge as existing techniques, such as the Compact Measurement Record (CMR), require more bandwidth with the addition of satellites, which may not be available, especially in constrained environments or at a premium cost.
Innovation Solution
The Compressed Measurement Record-Extended (CMRx) technique reduces data transmission by sending only ambiguous observation data, utilizing knowledge of signal structure and constellation geometry to eliminate redundant information, allowing for reconstruction of original data, and 'trickling' extraneous information to optimize bandwidth usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Compact Measurement Record (CMR) format is used to transmit GNSS data, then data transmission can be achieved, but the bandwidth requirement increases as more satellites are included in the constellation
Solution Approach 1:
The patent extracts and transmits only the essential ambiguous observation data (code phase and carrier phase measurements) while eliminating redundant information. By sending only the core measurement values without full satellite ephemeris or other derivable data, the system reduces bandwidth consumption while maintaining the ability to reconstruct complete observation sets at the receiver.
Solution Approach 2:
The transmission data is segmented into distinct components: ambiguous observation data, continuous tracking counters, and satellite visibility information. This segmentation allows each element to be transmitted efficiently with minimal overhead, reducing total bandwidth requirements compared to transmitting complete measurement records for each satellite.
2Measurement precision
If complete observation data is transmitted to ensure data integrity, then measurement precision is maintained, but the amount of data to be communicated increases
Solution Approach 1:
The receiver performs self-service by reconstructing complete observation data from the transmitted ambiguous measurements using locally stored satellite ephemeris and orbital information. This eliminates the need to transmit redundant data that the receiver can generate independently, reducing data volume while maintaining measurement precision through local computation of derived parameters.
Solution Approach 2:
Satellite ephemeris and orbital information are preliminarily loaded into the receiver before data transmission begins. This preliminary action enables the receiver to reconstruct complete observations from ambiguous measurements without requiring additional transmission of ephemeris data during operation, thereby reducing ongoing bandwidth requirements while preserving measurement integrity.
3Measurement precision
If more satellites are included in the GNSS constellation to improve positioning accuracy, then measurement precision increases, but bandwidth requirements increase
Solution Approach 1:
The system changes the parameter representation by transmitting ambiguous observation data with fewer bits compared to complete measurement records. By using continuous tracking counters instead of full measurement sequences and transmitting only essential observation components, the system reduces the data parameter size, enabling support for larger satellite constellations without proportionally increasing bandwidth consumption.
4Quantity of substance
If ambiguous observation data is transmitted to reduce bandwidth usage, then bandwidth efficiency improves, but data transmission complexity increases
Solution Approach 1:
The patent introduces continuous tracking counters as an intermediary element that bridges the simplified ambiguous data transmission and the receiver's data reconstruction process. These counters track satellite visibility and measurement continuity, providing the receiver with sufficient context to accurately reconstruct complete observations from minimal transmitted data, thereby managing complexity through structured intermediate representation.
Data Source
AI summary
A method of communicating satellite tracking information among a network of global navigation satellite system receivers is described. The method includes determining at a first GNSS receiver which satellites in a constellation of satellites have been continuously tracked over a preceding selected time period, and for each such satellite determining its elevation with respect to the zenith. Only the elevation value for the lowest satellite in the set of satellites for which all satellites of higher elevation values have been continuously tracked over the selected time period is then transmitted to the second GNSS receiver. That receiver can then reconstruct the set of satellites which have been continuously tracked.