Dead Reckoning Navigation Using Accelerometer Orientation Calibration
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Solution Overview
Problem
Existing dead reckoning systems for vehicle navigation require precise alignment of accelerometers, which is costly and time-consuming, and are ineffective in urban areas where GPS signals are blocked due to tall buildings or enclosed spaces.
Innovation Solution
A method and system that determine the orientation between the sensor frame and the vehicle's body frame using sensed accelerations, allowing for accurate conversion of accelerations to provide a dead-reckoning longitudinal acceleration without the need for precise accelerometer alignment, utilizing a combination of accelerometers and a GPS navigation system to calculate position updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If accelerometers are precisely aligned with the vehicle body frame, then velocity estimation accuracy is improved, but installation cost and time increase
Solution Approach 1:
The patent replaces the mechanical alignment approach with a computational solution. Instead of physically aligning accelerometers with the vehicle body frame during installation, the system uses a calibration process that determines the actual orientation of the accelerometer frame relative to the vehicle body frame through mathematical calculations. This substitution of mechanical precision requirements with computational correction resolves the contradiction by maintaining velocity estimation accuracy while dramatically simplifying installation.
Solution Approach 2:
The patent changes the parameter being controlled from physical orientation to mathematical transformation parameters. By determining the orientation angles (roll, pitch, yaw) between the accelerometer frame and vehicle body frame through calibration maneuvers and calculations, the system transforms the fixed mechanical alignment requirement into adjustable computational parameters that can be determined after installation, thereby reducing installation complexity while maintaining accuracy.
2Measurement precision
If GPS signals are received continuously, then position accuracy is improved, but navigation fails in urban areas with signal blockage
Solution Approach 1:
The patent prepares for GPS signal loss in advance by implementing a dead reckoning system using accelerometers. The system continuously collects acceleration data and maintains the capability to calculate position updates even when GPS signals are unavailable. This beforehand preparation ensures that navigation continues uninterrupted during signal blockage in urban areas, tunnels, or parking garages, thereby resolving the contradiction between position accuracy and adaptability to obstructed environments.
Solution Approach 2:
The patent introduces dead reckoning based on accelerometer data as an intermediary method between GPS signal availability and position updates. When GPS signals are blocked, the system uses the accelerometer-based dead reckoning as a bridge to maintain continuous position estimation. This intermediary approach allows the navigation system to transition smoothly between GPS-dependent and GPS-independent operation, maintaining both accuracy and reliability across different environmental conditions.
Data Source
AI summary
In one embodiment, a system and method of dead reckoning navigation for a vehicle uses a set of accelerometers. Sensed accelerometers from the set are converted into a vehicle body frame of reference set of accelerations. The resulting converted accelerations are then used to determine a dead-reckoning longitudinal acceleration for the vehicle. By integrating the longitudinal acceleration along a heading for the vehicle, a dead-reckoning-determined location for the vehicle is provided.