Sensor Fusion for 3D Position Estimation
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Solution Overview
Problem
Existing methods for estimating three-dimensional (3D) position and orientation of a moving object are either expensive, prone to errors over time, or face challenges in real-time precision due to interference and signal attenuation, particularly in consumer electronics applications.
Innovation Solution
A sensor fusion method that combines strength-based and inertia-based estimation using a weighted-sum approach, where strength-based estimation is adjusted for noise and fused with inertia-based estimation, utilizing Kalman Filter algorithms to improve accuracy and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If camera-based method is used to estimate 3D position, then location transformation from 2D images to 3D space is achieved, but high precision sensing is difficult due to dependency on camera resolution and marker size
Solution Approach 1:
The patent replaces the optical measurement system (camera-based 3D position estimation) with an inertial measurement system (accelerometer and gyro-sensor). Instead of using cameras to capture images and transform 2D coordinates to 3D positions, the invention uses inertial sensors to directly measure acceleration and angular velocity, which are then integrated to obtain position and orientation. This substitution eliminates the need for high-resolution cameras and large markers, thereby improving measurement precision while reducing device complexity requirements.
2Measurement precision
If ultrasonic wave method is used to calculate distance, then high precision sensing is achieved with relatively less expensive device, but real-time position estimation is difficult due to signal attenuation time of about 100 milliseconds
Solution Approach 1:
The patent replaces the ultrasonic wave measurement system with an inertial measurement system. Instead of transmitting ultrasonic waves and measuring the time of flight, the invention uses accelerometers and gyro-sensors to directly measure motion parameters. These inertial measurements are processed through integration to obtain position and orientation in real-time, eliminating the 100-millisecond signal attenuation delay inherent in ultrasonic methods and enabling true real-time position estimation.
3Loss of time
If inertial sensor method is used to calculate 3D position by integrating acceleration and angular velocity, then position estimation within short time period is achieved, but errors are accumulated over time making it inappropriate for long-time position estimating
Solution Approach 1:
The patent implements a feedback mechanism where the estimated position and orientation from inertial sensors are continuously compared with expected values or external reference data. The system uses this feedback to correct accumulated integration errors by adjusting the inertial measurement data or introducing corrective terms. This feedback loop enables the system to maintain reliable position estimation over extended periods, overcoming the limitation of error accumulation in pure inertial navigation.
4Ease of manufacture
If motion capturing device is made inexpensive and small-sized for consumer electronics applications, then accessibility is improved, but precision and reliability of 3D position and orientation estimation deteriorates
Solution Approach 1:
The patent combines multiple low-cost inertial sensors (accelerometer and gyro-sensor) into an integrated motion capturing device. By merging these complementary sensors and fusing their data through mathematical integration and sensor fusion algorithms, the system achieves accurate 3D position and orientation estimation. This combination approach allows the use of inexpensive, small-sized components while maintaining high measurement precision, making the device suitable for consumer electronics applications.
Data Source
AI summary
An apparatus and method for estimating a three-dimensional (3D) position and orientation based on a sensor fusion process is provided. The method of estimating the 3D position and orientation may include estimating a strength-based position and a strength-based orientation of a remote apparatus when a plurality of strength information is received, based on an attenuation characteristic of a strength that varies based on a distance and orientation, estimating an inertia-based position and an inertia-based orientation of the remote apparatus by receiving a plurality of inertial information, and estimating a fused position based on a weighted-sum of the strength-based position and the inertia-based position, and to estimate a fused orientation based on a weighted-sum of the strength-based orientation and the inertia-based orientation. The strength-based position and the strength-based orientation may be estimated based on a plurality of adjusted strength information from which noise is removed using a plurality of previous strength information.