Mobile Transmitter Position and Orientation Tracking
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Solution Overview
Problem
Existing methods for determining the position and orientation of a mobile transmitter, such as those used in real-time tracking systems, are hindered by measurement errors caused by arbitrary rotation, particularly when using linearly polarized transmitters and circularly polarized receivers, leading to position errors and requiring additional hardware for orientation estimation.
Innovation Solution
A system employing two linearly polarized antennas on the transmitter and a single circularly polarized antenna at each receiver, utilizing a field-theoretical model within a Kalman filter to separate and correct carrier phase measurements and transit times, allowing for accurate determination of position and orientation without additional hardware for orientation estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If carrier phase measurement is used in position calculation, then position precision is improved, but position error increases due to rotation of the transmitter
Solution Approach 1:
The patent converts the harmful effect of transmitter rotation on carrier phase measurements into a useful source of orientation information. By analyzing the phase changes caused by rotation, the system simultaneously determines both position and orientation of the mobile transmitter, transforming the previously harmful rotational interference into beneficial additional measurement data.
Solution Approach 2:
The patent changes the measurement parameters from using only carrier phase or only code phase to using a combination of both carrier phase and code phase measurements. This parameter change allows the system to maintain high position precision while compensating for rotation effects through the complementary nature of the two measurement types.
2Measurement precision
If additional hardware for orientation estimation is added, then orientation measurement capability is improved, but device complexity increases
Solution Approach 1:
The mobile transmitter serves itself by using its existing antennas to generate both position and orientation information. The system extracts orientation data from the carrier phase measurements that are already being taken for position determination, eliminating the need for separate orientation sensors or additional hardware components.
Solution Approach 2:
The existing transmitter antennas perform multiple functions: they are used both for determining position through carrier phase measurement and for determining orientation through analysis of phase changes during rotation. This multi-functionality eliminates the need for dedicated orientation measurement hardware.
3Reliability
If only code phase measurement is used, then rotation interference is eliminated, but position precision deteriorates
Solution Approach 1:
The patent merges carrier phase measurement and code phase measurement into a unified position determination process. By combining these two measurement methods, the system achieves both high precision (from carrier phase) and rotation insensitivity (from code phase), creating a synergistic effect that overcomes the limitations of using either method alone.
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 approach effectively eliminates position errors due to rotation and provides orientation and rotation rate information, reducing hardware requirements and improving tracking accuracy, especially for rotating transmitters like those on a ball.
Implementation Method 1
The transmitter emits linearly polarized waves
Implementation Method 2
The transmitter emits linearly polarized waves, as also e.g. is the case with a linear dipole. Circularly polarized antennas are used on the receiver side
Implementation Method 3
The received signals are used to determine transit times, so-called TOA values (Time Of Arrival), between the transmitter and the respective receivers
Data Source
AI summary
A method and an apparatus are proposed are proposed for determining the position and orientation of a mobile transmitter which has at least two linearly polarized antennas which are arranged at a predetermined angle with respect to one another. A plurality of receivers which can be synchronized with the mobile transmitter and the position of which is known, and which each have a circular-polarized antenna, in this case receive transmitted signals at a predetermined carrier frequency. According to the method, a field-theoretical model of the transmission path between the mobile transmitter and the receivers is created, which defines carrier-phase measured values, implements the field-theoretical model in a Kalman filter, and evaluates the received signals with respect to the carrier-phase measured values and/or propagation times. Finally, the position and orientation of the mobile transmitter are determined in the Kalman filter using the field-theoretical model and the carrier-phase measured values and/or propagation times determined from the received signals.