Vehicle Direction Detection Using Magnet and Sensor
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Solution Overview
Problem
Existing methods for determining a vehicle's movement direction, such as mechanical connection with transmission or complex GNSS systems, suffer from inaccuracies and sensitivity to errors, especially for slowly moving vehicles, and accelerometers provide unstable readings due to noise and bias, making it difficult to accurately detect direction independent of object structure and dynamics.
Innovation Solution
The proposed method compares the vector azimuth of vehicle movement from a GNSS receiver with a compass fixed on the vehicle, using a local geodetic coordinate system to determine if the vehicle is moving forward or backward, by calculating the angle between the movement vector and the prevailing moving direction, thereby avoiding mechanical connections and complex antenna systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If mechanical connection with transmission or wheels is used to detect movement direction, then the detection method is simple, but it requires mechanical connection and may have mismatch due to wheel slip or frictional sliding
Solution Approach 1:
The patent replaces mechanical connection methods with a magnetic field-based detection system. A magnet is attached to the vehicle body, and a magnetic sensor detects the magnet's position to determine movement direction, eliminating mechanical connections and wheel slip issues while maintaining simple device structure
Solution Approach 2:
The patent introduces a magnet as an intermediary element between the vehicle body and the detection system. The magnet serves as a reliable reference point that moves with the vehicle body, allowing accurate direction detection without direct mechanical connection between the sensor and vehicle structure
2Measurement precision
If rotating antennas with GNSS are used to determine movement direction, then position can be tracked, but it requires complex rotating antenna and separate computing device with high sensitivity to errors
Solution Approach 1:
The patent extracts only the essential function of direction detection from complex GNSS systems. Instead of using full GNSS positioning with rotating antennas, it uses a simple magnet and magnetic sensor to detect movement direction, eliminating unnecessary complexity while maintaining detection accuracy
Solution Approach 2:
The patent replaces expensive, complex GNSS rotating antenna systems with inexpensive magnetic sensors and magnets. The magnetic field detection method provides sufficient accuracy for direction detection at a fraction of the cost and complexity of GNSS-based solutions
3Device complexity
If accelerometers are used to detect movement direction, then no mechanical connection is needed, but accuracy is poor for slowly moving vehicles and readings are unstable due to noise and bias
Solution Approach 1:
The patent replaces accelerometer-based detection with magnetic field-based detection. The magnetic sensor tracks the position of a magnet attached to the vehicle body, providing stable and accurate direction detection without the noise and bias problems that plague accelerometer readings, especially at low speeds
4Loss of information
If inertial measurement unit is used for direction detection, then more comprehensive movement data is obtained, but robustness and reliability for slowly moving vehicles is not enough
Solution Approach 1:
The patent extracts only the essential direction detection function from complex inertial measurement units. By using a magnet and magnetic sensor to track the vehicle body's movement direction, it achieves reliable detection for both fast and slow movement without the complexity and reliability issues of IMU systems
Data Source
AI summary
A method of movement mode determination comprising measurement of vehicle's position and orientation and calculation of movement parameters, a compass on the vehicle, is azimuthally oriented along the prevailing and is mostly used movement direction (“forward” direction), a movement vector measurement unit, is used for measuring the azimuth of movement vector. A calculation unit being used for measuring an angle between vehicle movement vector azimuth measured by the movement vector measurement unit and vehicle azimuth measured by the compass fixed on the vehicle; movement is regarded as “backward” if the calculated angle is greater than 90 degrees, and “forward” if the calculated angle is smaller than 90 degrees. Also, an apparatus for movement direction determination includes a compass and a computation unit and further comprises a movement vector measurement unit for determining vehicle movement azimuth and connected through a signal connection to the computation unit.