Trajectory Predictor Using Up-Finding to Bound Inertial Drift
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Solution Overview
Problem
Inertial navigation systems face errors due to initial condition errors, model parameter errors, and unmodeled vehicle dynamics, leading to drift in navigation solutions, especially in environments without constant external aiding measurements.
Innovation Solution
A tightly coupled trajectory predictor system that uses constant up-finding measurements from an up-finding sensor to provide position, velocity, and attitude updates, bounding errors in the navigation solution by integrating these measurements with inertial navigation data through a model-based trajectory predictor and a Kalman filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If inertial navigation systems operate without constant external aiding measurements, then system independence and operational flexibility are improved, but navigation accuracy deteriorates due to drift errors
Solution Approach 1:
The patent introduces an up-finding sensor as an intermediary device that provides periodic external reference measurements without requiring constant external aiding. This mediator allows the inertial navigation system to maintain accuracy by bounding drift errors through intermittent up-finding measurements, resolving the contradiction between operational flexibility and navigation accuracy
Solution Approach 2:
The system employs periodic up-finding measurements instead of continuous external aiding. The up-finding sensor provides measurements at specific intervals when the vehicle's orientation allows, enabling the system to maintain accuracy while preserving operational flexibility in GNSS-denied environments
2Device complexity
If traditional trajectory predictors are used with intermittent external aiding, then device complexity is reduced, but error bounding capability deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where up-finding measurements are continuously integrated into the trajectory predictor to bound errors. The system uses these measurements to correct drift in position, velocity, and attitude estimates, maintaining reliability without significantly increasing system complexity
Solution Approach 2:
The patent merges the up-finding sensor measurements with the inertial navigation system and trajectory predictor into an integrated error bounding framework. This combination allows the system to maintain simplicity while improving error bounding capability through the synergistic integration of multiple data sources
Data Source
AI summary
Systems and methods for a tightly coupled trajectory predictor with constant up-finding are provided. In certain embodiments, a system includes an inertial measurement unit that provides inertial measurements of a vehicle. The system also includes an up-finding sensor that provides up-finding measurements based on when a portion of the vehicle is pointing up. Further, the system includes one or more processors that bound errors from the inertial measurements in a navigation solution during navigation of the vehicle using the up-finding measurements.