MEMS Dead Reckoning With Misalignment Angle Correction
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Solution Overview
Problem
Conventional navigation systems using GPS/GNSS signals become inaccurate in areas with weak or no signal, such as urban canyons or tunnels, leading to inaccurate location data, especially in ride-sharing and pedestrian navigation.
Innovation Solution
A method and system using MEMS sensors to determine the misalignment angle between the vehicle or pedestrian movement direction and the device's sensor heading, employing inertial measurement units (IMUs) and algorithms to calculate accurate location even without GPS/GNSS signals, by distinguishing between vehicle and pedestrian modes and using sensor fusion for real-time alignment adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS/GNSS signals are used for location detection, then location accuracy is improved in open areas, but location accuracy deteriorates in urban canyons or tunnels where signals are weak or unavailable
Solution Approach 1:
The system changes the measurement parameters by switching from GPS/GNSS signal-based location detection to IMU sensor-based dead reckoning when GPS/GNSS signals become weak or unavailable. This parameter change allows the system to maintain location tracking functionality in urban canyons and tunnels where satellite signals are blocked, thereby resolving the contradiction between location accuracy in open areas and location availability in signal-deprived environments
Solution Approach 2:
The system introduces an intermediary mechanism (IMU sensors and dead reckoning algorithms) that bridges the gap between GPS/GNSS signal availability and continuous location tracking. This intermediary allows the system to maintain location awareness during transitions between signal-rich and signal-poor environments, resolving the contradiction by providing a fallback measurement method that operates independently of satellite signals
2Reliability
If conventional dead reckoning is used to calculate current position, then location can be estimated without GPS/GNSS signals, but location accuracy deteriorates due to cumulative errors
Solution Approach 1:
The system implements feedback mechanisms where IMU sensor data is continuously processed and corrected based on available GPS/GNSS signals when present. This feedback loop allows the system to maintain accurate dead reckoning calculations by periodically resetting cumulative errors when satellite signals are available, thereby resolving the contradiction between maintaining location availability during signal loss and preserving location accuracy through error correction
Solution Approach 2:
The system dynamically adjusts the weighting and fusion of different sensor inputs (accelerometers, gyroscopes, magnetometers) based on environmental conditions and signal availability. This dynamic sensor fusion approach optimizes the dead reckoning algorithm's performance by adapting to changing conditions, thereby maintaining both location availability and improved accuracy compared to conventional static dead reckoning methods
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Provides accurate location information in GPS/GNSS signal-deprived environments by leveraging IMU data and sensor fusion, enhancing navigation accuracy in vehicles and pedestrian navigation.
Implementation Method 1
Gyroscopes are used in measuring angular velocity
Implementation Method 2
Accelerometers are used in measuring the acceleration forces (or rate of change of velocity)
Data Source
AI summary
A device including microelectromechanical systems (MEMS) sensors is used in dead reckoning in conditions where Global Positioning System (GPS) signals or Global Navigation Satellite System (GNSS) signals are lost. The device is capable of tracking the location of the device after the GPS/GNSS signals are lost by using MEMS sensors such as accelerometers and gyroscopes. By calculating a misalignment angle between a sensor frame of the device with either the movement direction of the vehicle or the walking direction of a pedestrian using the MEMS sensors, the device can accurately calculate the location of a user of the device even without the GPS/GNSS signals. Accordingly, a device capable of tracking the location of a pedestrian and a user riding in a vehicle without utilizing GPS/GNSS signals can be provided.