Inertial Navigation Hybridization via Multi-Subset Satellite Segmentation
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Solution Overview
Problem
Existing inertial navigation systems face challenges in ensuring the integrity of hybrid navigation using multi-constellation GNSS receivers, particularly due to limited access to raw measurements, high computational requirements for Kalman filters, and the inability to handle signals from multiple satellite constellations effectively.
Innovation Solution
An inertial navigation system that utilizes signals from multiple satellite subsets to calculate independent navigation solutions, detects satellite failures by comparing these solutions, and adapts by excluding the failed satellite, allowing for hybridization to resume with reduced navigation solutions using a limited number of Kalman filters suitable for lesser-capacity processors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bank of Kalman filters is used to ensure navigation integrity in close coupling hybridization, then the integrity of hybrid navigation is improved, but the device complexity and computational requirements increase significantly
Solution Approach 1:
The patent segments the satellite constellation into multiple subsets, with each subset processed by a separate Kalman filter. This segmentation reduces the total number of filters needed while maintaining integrity monitoring capability, as each filter handles a smaller, manageable portion of the satellite data independently.
Solution Approach 2:
The patent implements partial action by using a reduced set of Kalman filters that process only specific satellite subsets rather than all satellites. This partial processing approach maintains sufficient integrity monitoring for navigation purposes while significantly reducing computational complexity compared to processing the complete satellite constellation.
2Measurement precision
If all GNSS measurements including pseudo-ranges are accessed for integrity monitoring, then the measurement precision and integrity detection capability are improved, but the ease of operation is worsened due to receiver limitations
Solution Approach 1:
The patent makes the hybridization module universal by enabling it to operate with multiple types of input data: it can process both full raw GNSS measurements when available and limited navigation solutions when receivers restrict access. This multi-functionality allows the system to adapt to different receiver capabilities without requiring direct access to pseudo-range measurements.
Solution Approach 2:
The patent uses copying by creating multiple independent navigation solutions from different satellite subsets, then comparing these copied solutions to detect integrity issues. This approach enables integrity monitoring through solution comparison rather than direct measurement analysis, working around receiver access limitations.
3Device complexity
If a single constellation of satellites is processed, then the device complexity is reduced, but the adaptability is worsened for multi-constellation receivers
Solution Approach 1:
The patent segments the multi-constellation satellite system into separate subsets, allowing each Kalman filter to process specific constellations independently. This segmentation enables the system to handle multiple constellations (GPS, Glonass, Galileo, Compass) simultaneously while maintaining manageable computational complexity for each individual processing stream.
Solution Approach 2:
The patent implements dynamic adaptability by allowing the hybridization module to dynamically adjust which satellite subsets are processed based on available receivers and constellations. The system can flexibly configure the number and composition of satellite subsets, adapting to different operational scenarios and receiver capabilities without requiring fixed processing architecture.
Data Source
AI summary
An inertial navigation system using loose coupling hybridization of inertial measurements by utilizing measurements supplied by a satellite-positioning receiver which utilizes signals sent by a plurality of satellites distributed across at least two separate satellite subsets and calculates at least two navigation solutions, each navigation solution being calculated by means of signals sent by the satellites of one of the subsets. The inertial navigation system includes a hybridization module using each of the at least two calculated navigation solutions. A satellite failure detector is configured to compare the hybrid navigation solutions and where applicable detect incoherence between said hybrid navigation solutions. The hybridization module is configured to stop execution of hybridization following detection of incoherence between the hybrid navigation solutions when the origin of the incoherence cannot be determined.