Indoor Positioning Using Circular Polarization Against Multipath
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Solution Overview
Problem
Existing methods for position determination inside buildings face significant challenges due to multipath influences, which cause interfering signals, signal attenuation, and delay, making precise position determination difficult or impossible.
Innovation Solution
A method using at least four transmitters that transmit circularly polarized signals of different frequencies closely adjacent to each other, allowing a receiver to determine its position with high precision by evaluating the received signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional radio-based position determination methods are used inside buildings, then position determination can be performed, but multipath influences cause interfering signals that make precise position determination difficult or impossible
Solution Approach 1:
The patent applies polarization properties (analogous to color changes) by using circularly polarized signals. The receiver is configured to receive only circularly polarized signals, which allows it to distinguish direct signals from reflected signals, as reflections typically change the polarization state. This enables precise position determination by filtering out multipath-influenced signals.
2Adaptability or versatility
If code division multiplexing is used to enable simultaneous transmission of different user data streams, then frequency spreading increases propagation time differences, but wideband receivers require increased power consumption
Solution Approach 1:
The patent changes the parameter of signal polarization from linear to circular, and uses closely spaced frequencies with circular polarization discrimination. This allows simultaneous transmission of multiple signals without requiring wideband receivers, thereby reducing power consumption while maintaining adaptability for multiple users.
3Device complexity
If transmitters use linearly polarized signals, then signal transmission is simple, but reflected signals cannot be distinguished from direct signals
Solution Approach 1:
The patent uses circularly polarized signals instead of linearly polarized signals. When signals are reflected, their polarization state changes, allowing the receiver to distinguish between direct and reflected signals. This maintains relative simplicity while significantly improving measurement precision by enabling signal discrimination.
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 enables precise position determination inside buildings with high accuracy, even in densely built-up areas and underground, by minimizing multipath influences and reducing power consumption.
Implementation Method 1
at least four transmitters transmit circularly polarized signals
Implementation Method 2
a receiver to be localized receives the circularly polarized signals
Data Source
AI summary
The invention relates to a method and a system for position determination of at least one object, in particular inside a building. In a method for position determination of at least one object, at least four transmitters transmit circularly polarized signals and a receiver to be localized receives the circularly polarized signals. At least two and in particular all transmitters transmit periodic signals of different frequencies, these frequencies being closely adjacent.