3D Positioning System Corrects INS Drift via Terrain-Aided Navigation
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Solution Overview
Problem
Current navigation systems, such as GPS/INS integration, face challenges with precision errors due to sensor drift over time and signal interruptions in urban or indoor areas, necessitating improved methods for precise positioning and elevation data, especially when GPS is unavailable.
Innovation Solution
A method integrating INS, Radar, Barometric Altimeter, and DTED-2 data using a 3D positioning system that corrects INS errors with terrain elevation data, employing a Covariance Intersection (CI) method for data fusion, generating precise position and elevation data even without GPS, and improving accuracy when GPS is available.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS/INS integration is used, then positioning reliability is improved, but positioning precision deteriorates due to sensor drift over time
Solution Approach 1:
The patent introduces terrain elevation data as an intermediary element to correct INS drift errors. By comparing the actual terrain elevation under the vehicle with the known terrain map data, the system generates position corrections that compensate for INS accumulated errors, thereby maintaining both reliability and precision over extended periods
Solution Approach 2:
The system implements a feedback mechanism where terrain elevation measurements continuously correct INS position estimates. The corrected position information is fed back to update the navigation solution, creating a closed-loop system that prevents drift accumulation and maintains positioning precision throughout the mission duration
2Adaptability or versatility
If GPS signal is used in urban or indoor areas, then positioning availability is improved, but positioning precision deteriorates due to signal interruptions and jamming
Solution Approach 1:
The patent uses terrain elevation data as an intermediary to bridge GPS interruptions. When GPS signals are unavailable or degraded in urban canyons or indoor environments, the system switches to terrain-aided navigation mode, using the terrain map as a reference to maintain positioning precision without continuous GPS input
Solution Approach 2:
The system pre-loads terrain elevation maps and prepares terrain-aided navigation algorithms before GPS signal loss occurs. This beforehand preparation ensures that when GPS interruptions happen in challenging environments, the system can immediately transition to alternative positioning methods without precision degradation
3Measurement precision
If INS is used for short-term positioning, then positioning precision is improved, but positioning reliability deteriorates due to drift errors over time
Solution Approach 1:
The patent implements continuous terrain-aided correction that operates throughout the entire navigation mission. Rather than periodic updates, the system continuously compares terrain measurements with map data and applies corrections to INS position estimates, ensuring both short-term precision and long-term reliability through uninterrupted correction
Solution Approach 2:
The system merges INS short-term precision capabilities with terrain-aided long-term correction. By combining these two complementary approaches, the system achieves both high short-term positioning precision from INS and sustained long-term reliability from continuous terrain-based drift correction
Data Source
AI summary
A precise positioning method provides a 3D position data in the absence of GPS by correcting the INS error, which generates a precise altitude data in the presence of GPS by integrating the outputs of all the sources providing altitude data and which generates a precise position data by using the INS/GPS integrated system position data. The method is performed by processing the data from relative sensors in the platforms comprising INS which generates the data necessary for terrain-aided navigation, radar altimeter and barometric altimeter sensors, and DTED which is a database comprising the elevation above sea level of the relevant terrain.