Dead-Reckoning Guidance System Cardinal Direction Coordinate Corrections
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Solution Overview
Problem
Existing navigation systems, such as GPS, are unreliable in environments like tunnels or urban canyons where satellite signals are blocked, and there is a need for a method to accurately track vehicle position and direction without relying on satellite data.
Innovation Solution
A dead-reckoning guidance system that uses wheel sensors and an inertial measurement unit to determine vehicle speed and distance traveled, applying coordinate corrections based on distance and direction relative to cardinal directions to minimize positional errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dead-reckoning is used to track vehicle position without GPS, then navigation is available in GPS-denied environments, but positional accuracy deteriorates over time due to accumulated errors
Solution Approach 1:
The system applies periodic coordinate corrections to the dead-reckoning position based on cardinal direction alignments (north-south, east-west). When the vehicle travels along cardinal directions, the system corrects accumulated positional errors by snapping coordinates to a standardized grid, thereby periodically resetting error accumulation while maintaining continuous navigation availability
Solution Approach 2:
The system implements feedback by continuously monitoring vehicle heading and distance traveled, comparing actual position against expected position based on cardinal direction travel. This feedback mechanism triggers coordinate corrections when specific conditions are met, allowing the system to self-correct positional drift without external GPS references
2Measurement precision
If coordinate corrections are applied frequently to maintain accuracy, then positional precision is improved, but computational complexity increases
Solution Approach 1:
The system applies coordinate corrections selectively based on local conditions - specifically when the vehicle is traveling along cardinal directions (north-south or east-west). This localized approach to correction, rather than continuous correction, reduces computational complexity while maintaining accuracy where it matters most along primary navigation corridors
Solution Approach 2:
The system changes the parameter of coordinate correction application from continuous to conditional-based on vehicle heading and travel direction. By monitoring heading parameters and only applying corrections during cardinal direction travel, the system reduces the frequency of computational operations while maintaining positional accuracy during critical navigation segments
Data Source
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AI summary
A dead-reckoning guidance system (10) determines a vehicle-speed (22) of the host-vehicle (12) based on wheel-signals (20) from the one or more wheel-sensors (18); determines a distance-traveled (24) by the host-vehicle (12) during a time-interval (36) since prior-coordinates (38) of the host-vehicle (12) were determined; determines a heading-traveled (48) of the host-vehicle (12) during the time-interval (36) since the prior-coordinates (38) of the host-vehicle (12) were determined; determines present-coordinates (40) of the host-vehicle (12) based on the distance-traveled (24) and the heading-traveled (48); determines when the vehicle-speed (22) is greater than a speed-threshold (52); determines when the heading-traveled (48) differs from a cardinal-direction (46) by both greater than a noise-threshold (54) and less than an angle-threshold (56); and in response to a determination that both the vehicle-speed (22) is greater than the speed-threshold (52) and that the heading-traveled (48) differs from the cardinal-direction (46) by both greater than the noise-threshold (54) and less than the angle-threshold (56), determines a coordinate-correction (42) to apply to the present-coordinates (40), said coordinate-correction (42) determined in accordance with the distance-traveled (24) and the cardinal-direction (46).