Wireless Positioning Using Base Station Phase Differences
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Solution Overview
Problem
Existing positioning methods using satellite and ground mobile communication base station signals face significant errors in downtown and mountainous areas due to signal reflection, diffraction, and synchronization issues, limiting precision to several meters or more, and are unsuitable for indoor use.
Innovation Solution
A positioning method and apparatus that calculates terminal location by measuring phase differences between wireless signals from three or more adjacent base stations, using start point information and 3D map data to correct for diffraction paths and minimize errors, with a system comprising a reception unit, phase tracking unit, and control unit to synchronize phase clocks and filter signals within specific incident angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS satellite signals are used for positioning, then positioning precision can reach 1-meter level in good conditions, but error increases to several meters or more in downtown or mountainous areas due to signal reflection and diffraction
Solution Approach 1:
The patent introduces ground-based base stations as intermediary devices to establish direct line-of-sight communication paths with the terminal. These base stations act as mediators between the terminal and positioning system, transmitting reference signals that are less susceptible to atmospheric interference and satellite signal blockage, thereby maintaining positioning reliability in challenging environments
Solution Approach 2:
The patent replaces satellite-based electromagnetic positioning with ground-based wireless communication signals for positioning. By substituting the satellite signal mechanism with terrestrial base station signals, the system eliminates dependence on atmospheric conditions and satellite visibility, achieving stable positioning in urban canyons and mountainous areas where satellite signals fail
2Measurement precision
If GPS carrier phase method is used to achieve centimeter-level positioning precision, then positioning precision is significantly improved, but phase slip occurs when terminal moves at fast speed or signal is blocked, causing positioning error
Solution Approach 1:
The patent employs periodic reference signals transmitted at regular intervals from base stations. This periodic transmission allows the terminal to continuously track phase information without requiring uninterrupted satellite carrier signals, reducing phase slip occurrences during movement or temporary blockage by providing frequent reference updates
Solution Approach 2:
The terminal performs autonomous phase tracking and positioning calculation using locally received base station reference signals. By self-managing the positioning process without continuous external satellite carrier dependency, the system maintains positioning continuity even when satellite signals are temporarily blocked or during high-speed movement
3Adaptability or versatility
If ground mobile communication base station signal is used for positioning, then positioning can be performed without GPS, but positioning error of several meters to tens of meters occurs due to bandwidth and sampling time interval limitations
Solution Approach 1:
The patent changes the signal parameters by using wideband reference signals with optimized time-frequency characteristics. By modifying the signal bandwidth, sampling rate, and waveform structure specifically for positioning purposes, the system overcomes the limitations of conventional mobile communication signals, achieving centimeter-level precision while maintaining GPS-independent operation
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 reduces positioning errors and achieves precise location calculation even in challenging environments, such as downtown or mountainous areas, and maintains accuracy in high-speed vehicle scenarios, enhancing positioning reliability and precision beyond traditional bandwidth limitations.
Implementation Method 1
calculating a difference in phase angles between carrier signals of two BSs, while changing the two BSs, by using the start point information of the carrier signals of the two BSs among the three or more BSs; calculating differences in distances of arrival from the corresponding two BSs to the terminal by using the calculated differences in phase angles
Data Source
AI summary
A terminal that receives carrier signals with start point information indicated thereon from three or more base stations (BSs) including a serving BS, calculates a difference in phase angles between carrier signals of two BSs while changing the two BSs by using the start point information of the carrier signals of the two BSs among the three or more BSs, and calculates coordinates of the terminal by using the calculated differences in distance of arrival is provided.