Small Space Positioning Using Dual-Domain Correlation Analysis
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Solution Overview
Problem
Existing small space positioning systems face challenges in achieving accurate and unambiguous positioning, particularly in environments with multi-path signals, where the overlap of correlation curves complicates the identification of the original line of sight (LOS) peak, leading to reduced accuracy and increased ambiguity.
Innovation Solution
A system and method that transmit a modulated continuous wave including a carrier signal and a base-band signal, with a receiving unit performing cross-correlation analysis to determine the position by identifying peaks in both absolute and real correlation curves, using an ambiguity resolver to select the most likely LOS distance based on parameters such as history tracking, velocity, and scoring systems, and comparing signals from multiple receivers to resolve ambiguity and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cross-correlation analysis is used to determine position, then positioning accuracy is improved, but ambiguity increases in the presence of multi-path signals
Solution Approach 1:
The patent extends the correlation analysis from one dimension (magnitude only) to two dimensions by separately analyzing both the magnitude (absolute correlation) and phase (real correlation) of the correlation function. This dimensional extension allows the system to distinguish between LOS and multi-path signals by examining their different phase characteristics, thereby resolving ambiguity while maintaining high positioning accuracy.
Solution Approach 2:
The patent treats the correlation function as having two 'colors' or components: the absolute correlation (magnitude) and the real correlation (phase). By analyzing both components separately and comparing their peaks, the system can identify LOS signals versus multi-path signals, similar to how different colors can be used to distinguish different objects. The LOS peak and multi-path peak exhibit different characteristics in these two correlation domains, enabling reliable discrimination.
2Device complexity
If only absolute correlation is analyzed, then computation is simplified, but positioning accuracy deteriorates due to inability to resolve phase information
Solution Approach 1:
The patent segments the correlation analysis into two distinct parts: absolute correlation analysis and real correlation analysis. Each part serves a specific purpose - absolute correlation provides the overall signal strength and timing, while real correlation provides phase information. By processing these segments separately and combining their results, the system achieves high positioning accuracy without overwhelming computational complexity.
Solution Approach 2:
The patent applies partial action by not requiring complete analysis of all signal characteristics. Instead, it focuses on the two most critical aspects (magnitude and phase of correlation) and uses their peak comparison to resolve positioning. This selective approach achieves sufficient accuracy without the need for more complex full-signal analysis methods.
3Reliability
If multiple correlation peaks are present, then more signal paths are detected, but ambiguity in identifying LOS peak increases
Solution Approach 1:
The patent introduces the real correlation function as an intermediary tool to mediate between the multiple correlation peaks and the LOS peak identification. The real correlation provides phase information that acts as a discriminator, allowing the system to distinguish which of the multiple peaks corresponds to the LOS signal. This intermediary analysis resolves the ambiguity that would otherwise exist when multiple peaks are present in the absolute correlation 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
The solution achieves improved accuracy in small space positioning, capable of determining positions within the order of one tenth of a wavelength, and effectively resolves ambiguity in the presence of multi-path signals, enhancing the reliability of the positioning system.
Implementation Method 1
transmitting device, movable within an approximate range, configured for transmitting a modulated continuous wave, wherein the modulated continuous wave includes a carrier signal and a base-band signal
Implementation Method 2
distances determined from the outputs of the receivers are triangulated and correlated to absolute pen positions. Typically, the position measurements are based on measuring the Time Of Flight (TOF) of the transmitted pulses through a Line Of Sight (LOS)
Data Source
AI summary
A system for small space positioning comprises a transmitting device, movable within an approximate range, configured for transmitting a modulated continuous wave, wherein the modulated continuous wave includes a carrier signal and a base-band signal, and a receiving unit configured for receiving signal (s) transmitted by the transmitting device and for determining a position of the transmitting device within the approximate range based on analysis of both the carrier signal and the base-band signal received from the transmitting device.