Phased Array Receiver Yaw Estimation via RF Phase Difference
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Solution Overview
Problem
Existing orientation estimation methods in mobile devices face challenges due to noise and time-varying biases in accelerometers and gyroscopes, particularly in environments with varying conditions such as those found in portable electronics, where sensing errors from gyro bias and temperature drift are significant.
Innovation Solution
A method that combines orientation information from an inertia measurement unit (IMU) with a phased array receiver, using the phase difference of an RF signal to determine the angle of incidence and thereby improve the accuracy of yaw estimation by projecting a vector onto a plane, thereby enhancing overall orientation determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If accelerometer and gyroscope measurements are used for orientation estimation, then orientation information can be obtained, but measurement precision deteriorates due to noise and time-varying biases
Solution Approach 1:
The patent combines measurements from multiple sensors (accelerometer, gyroscope, and magnetometer) into a unified orientation estimation system. By merging data from these different sensor types, the system compensates for individual sensor deficiencies - the accelerometer provides gravity reference, the gyroscope provides angular velocity, and the magnetometer provides magnetic field direction, together achieving more reliable orientation estimation than any single sensor could provide
Solution Approach 2:
The patent implements sensor fusion algorithms that continuously process and update orientation estimates based on incoming sensor data. The system uses feedback mechanisms to detect drift and bias in gyroscope measurements over time, then corrects these errors by referencing the accelerometer and magnetometer data, maintaining measurement precision despite individual sensor degradation
2Measurement precision
If sensor fusion algorithms are used to mitigate sensing errors, then orientation accuracy improves, but device complexity increases
Solution Approach 1:
The patent designs a sensor fusion system where the same set of sensors (accelerometer, gyroscope, magnetometer) serves multiple functions: the accelerometer provides both gravity reference for pitch/roll estimation and helps detect device motion states; the gyroscope provides angular velocity for orientation integration and helps detect rapid movements; the magnetometer provides heading reference and helps correct gyroscope drift. This multi-functional use of sensors achieves high orientation accuracy without requiring additional specialized sensors, thereby limiting complexity increase
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
This method enhances the accuracy of orientation estimation by reducing sensor fusion errors and providing more precise yaw measurements, even in environments with significant sensing errors and varying conditions.
Implementation Method 1
detecting the difference between phases of an RF signal received by at least a pair of receive elements of the phased array receiver, determining the angle of incidence of the RF signal in accordance with the phase difference
Implementation Method 2
a micromachined mass-spring-damper combined with a parallel plate capacitor arrangement may be used to determine the linear acceleration
Implementation Method 3
A triaxial accelerometer provides a measure of acceleration which is the sum of Earth's gravitational field (static acceleration) and the rigid body's acceleration (dynamic acceleration)
Implementation Method 4
A triaxial gyroscope provides a measure of the angular velocity
Data Source
AI summary
A method of determining the orientation of a device having disposed therein, in part, an inertia measurement unit, a phased array receiver, and a controller, includes, in part, detecting the difference between phases of an RF signal received by at least a pair of receive elements of the phased array receiver, determining the angle of incidence of the RF signal from the phase difference, using the angle of incidence to determine the projection of a vector on a plane of an array of transmitters transmitting the RF signal, and determining the yaw of the device from the projection of the vector. The vector is a three-dimensional vector representative of the orientation of the plane of the phased array receivers relative to the plane of the array of transmitters transmitting the RF signal.