MEMS Inertial Navigation for GPS-Denied Vehicle Dead Reckoning
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Solution Overview
Problem
Existing location-based applications and dead reckoning methods become inaccurate when GPS/GNSS signals are weak or unavailable, particularly in urban canyons or tunnels, leading to challenges in ride-hailing services and collision analysis.
Innovation Solution
A standalone device equipped with MEMS sensors, a processor, and a wireless transmitter/receiver calculates a misalignment angle between a vehicle reference frame and a device reference frame using methods like SVD, OTE, and GNSS DCM, enabling accurate location determination even in GPS/GNSS-denied environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS/GNSS sensors are used for location identification, then location accuracy is improved in open environments, but location accuracy deteriorates in urban canyons or tunnels where signals are weak or unavailable
Solution Approach 1:
The patent combines GPS/GNSS sensors with MEMS sensors (accelerometers and gyroscopes) into an integrated navigation system. The system merges satellite-based positioning with inertial measurement to maintain location accuracy in environments where GPS signals are weak or unavailable, such as urban canyons and tunnels.
Solution Approach 2:
The patent introduces dead reckoning as an intermediary method that bridges the gap between GPS availability periods. By using MEMS sensor data to calculate position changes over time, the system maintains continuous location tracking even when direct GPS signals are blocked, serving as a mediator between GPS-denied environments.
2Reliability
If conventional dead reckoning is used to calculate current position, then location can be estimated without GPS signals, but accuracy is insufficient for precise location-based applications
Solution Approach 1:
The patent changes the parameters used in dead reckoning by incorporating data from both accelerometers and gyroscopes, along with vehicle motion status information. This multi-parameter approach improves the accuracy of position calculation compared to conventional dead reckoning that relies on limited sensor data.
Solution Approach 2:
The system uses feedback mechanisms to continuously refine position estimates by comparing expected motion based on sensor data with actual motion patterns. The processor analyzes accelerometer and gyroscope data along with vehicle status to correct and improve dead reckoning accuracy over time.
3Reliability
If a standalone device with MEMS sensors is used, then the device can provide location information in GPS-denied environments, but the device complexity increases compared to simple GPS receivers
Solution Approach 1:
The standalone device is designed with multi-functionality, serving both as a GPS receiver and an inertial measurement unit. The same processor and sensor suite handle both satellite-based positioning and dead reckoning operations, allowing the device to function reliably across diverse environments without requiring separate specialized systems.
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 and collision analysis by aligning sensor data, enhancing ride-hailing services and collision detection in both autonomous and human-operated vehicles.
Implementation Method 1
Accelerometers are used in measuring the acceleration forces or rate of change of velocity
Implementation Method 2
Gyroscopes are used in measuring angular velocity
Data Source
AI summary
A device including microelectromechanical systems (MEMS) sensors are 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 forward axis of a sensor frame of the device and a forward axis of a vehicle frame using the data received from the MEMS sensors, the device can accurately calculate the location of a user or the vehicle of the device even without the GPS/GNSS signals. Accordingly, a device capable of tracking the location of the user riding in the vehicle in GPS/GNSS signals absent environment can be provided.