Relative RSTD Calculation for Positioning Error Elimination
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Solution Overview
Problem
Existing positioning methods, such as UTDOA and OTDOA, suffer from positioning errors due to timing alignment errors (TAE) between base station clocks, leading to inaccuracies in determining the location of mobile terminals.
Innovation Solution
The method involves calculating relative Reference Signal Time Differences (RSTD) by subtracting the measured RSTDs of two mobile terminals to eliminate TAE, thereby improving positioning precision and allowing for accurate location determination of multiple mobile terminals in a single operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RSTD is measured using traditional UTDOA or OTDOA positioning methods, then positioning can be performed, but positioning precision deteriorates due to TAE introduction
Solution Approach 1:
The patent extracts and eliminates the TAE component from the RSTD measurement by introducing a second mobile terminal as a reference. The relative RSTD calculation separates the desired positioning information from the clock synchronization error, removing the harmful TAE effect from the positioning calculation.
Solution Approach 2:
The second mobile terminal acts as an intermediary reference object. By measuring RSTD between two mobile terminals and subtracting it from the RSTD of the first mobile terminal, the patent creates a relative measurement that uses the second terminal as a mediator to cancel out the base station clock errors.
2Productivity
If multiple mobile terminals are positioned simultaneously using traditional methods, then system capacity increases, but positioning accuracy deteriorates due to cumulative TAE effects
Solution Approach 1:
The patent merges the positioning measurements of multiple mobile terminals into a relative RSTD framework. By combining the RSTD measurements of multiple terminals and expressing them relative to a common reference, the method enables simultaneous positioning while maintaining accuracy through the cancellation of common TAE components.
3Measurement precision
If base station clocks are perfectly synchronized to eliminate TAE, then positioning precision improves, but system complexity and synchronization requirements increase
Solution Approach 1:
The patent converts the harmful TAE effect into a beneficial reference signal. Instead of treating the clock synchronization error as something to be eliminated through complex synchronization systems, the method uses the TAE as a common reference that cancels out in differential measurements, turning the problem into a solution.
Data Source
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AI summary
Embodiments of the present invention provide a positioning method, a positioning server, and a positioning system, to eliminate a positioning error brought by a TAE, improve positioning precision, and accurately position multiple mobile terminals at a time. The positioning method includes: separately obtaining, by a positioning server, location coordinates of M positioning nodes; separately obtaining, by the positioning server, a reference signal time difference RSTD between an ith positioning node and an (i+1)th positioning node in the M positioning nodes and a jth mobile terminal in two mobile terminals; determining, by the positioning server, a relative RSTD according to the RSTD; and determining, by the positioning server, location coordinates of the two mobile terminals according to the relative RSTD and the location coordinates of the M positioning nodes. The present invention is applicable to the field of wireless communications technologies.