Inertial Navigation Initialization with Latency Compensation
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Solution Overview
Problem
Real-time inertial navigation systems face initialization errors due to latency in aiding source data, which can result in significant position, velocity, and attitude errors, especially in dynamic environments where the latency of aiding source data is not accounted for.
Innovation Solution
The method involves receiving inertial measurement data and storing it in a buffer with a time of validity, then using this data to initialize a navigation solution and apply coning or sculling compensation to propagate the solution forward, effectively mitigating latency-induced errors by compensating for inertial motion estimates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If aiding source data is used for initialization, then the navigation system can provide initial position, velocity, and attitude, but the latency in aiding source data introduces errors into the navigation solution
Solution Approach 1:
The system performs preliminary buffering of inertial measurement data before the aiding source data becomes available. By pre-processing and storing inertial data in a buffer with coning and sculling compensation, the system prepares compensated motion estimates in advance, eliminating the need to use delayed aiding data for initialization and thereby resolving the latency-accuracy contradiction
Solution Approach 2:
The patent introduces an intermediary buffer that stores inertial measurement data and provides compensated estimates as a bridge between the inertial sensor and the aiding source. This intermediary mechanism allows the system to use the buffered compensated data instead of delayed aiding data, resolving the contradiction by mediating the timing mismatch between data sources
2Measurement precision
If inertial measurement data is buffered and compensated, then latency-induced errors are reduced, but the computational complexity increases
Solution Approach 1:
The system changes the parameters of inertial data processing by applying coning and sculling compensation algorithms that transform raw inertial measurements into compensated motion estimates. These parameter transformations (applying specific compensation models) improve accuracy by accounting for inertial effects during the buffering period, while the algorithms are designed to be computationally efficient
Solution Approach 2:
The patent replaces complex real-time aiding data processing with a simplified buffer-based approach using pre-computed compensated inertial estimates. Instead of dealing with delayed aiding data and complex synchronization, the system substitutes a more straightforward mechanism of storing and retrieving pre-compensated inertial motion estimates, reducing overall computational complexity while maintaining high accuracy
Data Source
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AI summary
An example embodiment includes a method for initializing a navigation system. The method includes receiving inertial measurement data from an inertial measurement unit over time and storing the inertial measurement data in a buffer with an indication of a time of validity for the inertial measurement data. The method also includes receiving navigation data from an aiding source, the navigation data having a time of validity, and initializing a navigation solution with the navigation data. The method also includes summing inertial measurement data from the buffer to produce an inertial motion estimate for a time increment after the time of validity of the navigation data, applying at least one of coning or sculling compensation to the inertial motion estimate to produce a compensated inertial motion estimate, and propagating the navigation solution forward based on the compensated inertial motion estimate.