Multi-Beacon Location System Multipath Interference
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Solution Overview
Problem
Existing beacon-based range estimation technologies face challenges in accurately estimating distance due to multipath interference, which leads to errors in proximity location systems, especially in environments with complex morphology.
Innovation Solution
A multi-beacon system that transmits two correlated beacon signals with different wavelengths, spaced apart to decorrelate multipath effects, allowing a mobile processor-based device to receive and process these signals independently to estimate distance based on signal strength trends, using correlation functions to filter out irregularities caused by multipath interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single beacon signals are used for range estimation, then the system complexity is low, but measurement precision deteriorates due to multipath interference
Solution Approach 1:
The patent divides a single beacon into multiple beacons (first and second beacons) that transmit correlated signals. By segmenting the signal source into multiple spatially separated beacons, the system can decorrelate multipath effects while maintaining signal correlation, thereby improving distance estimation accuracy without requiring complex processing at the receiver端.
Solution Approach 2:
The patent introduces correlated signals as an intermediary mechanism between the beacons and the receiver. These correlated signals serve as a mediator that allows the receiver to distinguish between direct path and multipath components by analyzing signal correlations, thus improving measurement precision while keeping the receiver relatively simple.
2Measurement precision
If multiple beacons are used to reduce multipath effects, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent combines multiple beacons into a coordinated multi-beacon system that transmits correlated signals. By merging the functionality of multiple beacons and using signal correlation techniques, the system achieves improved measurement precision while managing complexity through coordinated operation rather than independent processing at each beacon.
Solution Approach 2:
The patent changes the spatial parameter by spacing beacons apart by distances between one and four wavelengths. This parameter change optimizes the decorrelation of multipath effects while maintaining signal correlation, achieving improved measurement precision with a relatively simple configuration that doesn't require complex processing.
3Length of stationary object
If beacons are spaced closely together, then the system occupies less space, but multipath interference increases reducing measurement precision
Solution Approach 1:
The patent optimizes the spacing parameter by positioning beacons at distances between one and four wavelengths apart. This specific parameter range achieves the optimal balance: close enough to maintain signal correlation for accurate ranging, but far enough to decorrelate multipath effects from different spatial paths, thereby improving measurement precision without excessive spacing.
4Adaptability or versatility
If RF technologies are used for ranging, then communication functionality is maintained, but reliability deteriorates due to parasitic effects like multipath interference
Solution Approach 1:
The patent introduces signal correlation analysis as an intermediary processing step between receiving RF signals and determining distance. This intermediary mechanism allows the system to use standard RF communication technologies while filtering out parasitic effects like multipath interference through correlation-based processing, thereby improving reliability without sacrificing communication compatibility.
Solution Approach 2:
The patent converts the parasitic multipath interference, which normally degrades reliability, into a useful signal characteristic. By using correlated signals from multiple beacons, the multipath components become distinguishable from direct path signals through correlation analysis, transforming the harmful interference into additional information that can be used to improve range estimation reliability.
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 enhances the accuracy and precision of distance estimation by attenuating the effects of multipath fading, reducing false alarms and improving the reliability of proximity location systems in diverse environments.
Implementation Method 1
these RF technologies have parasitic effects (e.g., multipath interference) which may undesirably limit the ability of these RF technologies to estimate range
Implementation Method 2
correlates the trends of the signal strengths of the received first and second RF signals; and estimates a distance between the mobile processor-based device and the multi-beacon system based at least in part on the correlation of the trends
Data Source
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AI summary
Systems and methods for providing improved accuracy for beacon-based location systems. A location estimation system may include a multi-beacon system which includes two or more beacons positioned proximate each other. The beacons emit correlated beacon frames which are time and data correlated. A mobile device receives the beacon signals and processes them to estimate the distance between the mobile device and the multi-beacon system. The mobile device processes the signals based on a correlation function of the beacons signal strength trends, which indicates homogeneity and reliability of the acquired signals. When the correlation is high, the two or more RSSI signals are stable and may be used for the distance estimation. When the correlation is low, at least one of the signals is irregular. The mobile device compensates for the irregular signal, thus improving distance estimation accuracy.