Reference Station Signal Synchronization via Mutual Exchange
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Solution Overview
Problem
Existing radio location systems face challenges in achieving high precision due to the need for precise synchronization of stations, which is complex and expensive to implement, and previous methods are limited by assumptions such as line-of-sight requirements and clock accuracy, leading to systematic measurement errors and insufficient accuracy for phase-coherent measurements.
Innovation Solution
A wave-based method where at least two reference stations transmit signals simultaneously in the same frequency range, with one station receiving and determining the time offset or phase position of its own signal relative to another station's signal, allowing for high-precision synchronization and location determination without additional devices, and using multiplex methods like FMCW or CDMA to separate signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fiber optic network is used for system-wide time reference, then synchronization accuracy is improved, but device complexity and initial investment cost increase significantly
Solution Approach 1:
The patent extracts the synchronization reference function from the complex fiber optic infrastructure and implements it through wireless signal exchange between stations. Each station determines time offsets by receiving and processing signals from other stations, eliminating the need for dedicated fiber optic synchronization networks while achieving comparable accuracy.
Solution Approach 2:
The patent introduces signal propagation time measurements as an intermediary mechanism to achieve synchronization. Instead of directly distributing time references through fiber optics, stations use radio signal exchange and TDOA measurements to indirectly determine their relative time offsets, reducing infrastructure complexity.
2Reliability
If additional fixed stations transmit synchronization signals, then synchronization is achieved, but measurement accuracy is limited by line-of-sight requirements and clock accuracy assumptions
Solution Approach 1:
The patent inverts the traditional synchronization approach by having stations determine time offsets through mutual signal exchange and TDOA measurements rather than receiving synchronization signals from a central authority. This inversion eliminates dependence on line-of-sight assumptions and perfect clock accuracy, as the method actively measures and compensates for these factors.
Solution Approach 2:
The patent changes the measurement parameters from assuming perfect clocks and line-of-sight conditions to actively measuring signal propagation times and clock offsets. By using TDOA measurements and determining time offsets through signal exchange, the system adapts to real-world conditions rather than requiring idealized assumptions.
3Ease of operation
If time-of-arrival differences are evaluated, then positioning is possible, but positioning accuracy deteriorates due to lack of precise station synchronization
Solution Approach 1:
The patent implements feedback by having stations continuously exchange signals and determine time offsets based on measured TDOA values. These determined time offsets are then used to correct and refine positioning calculations, creating a closed-loop system that improves accuracy through iterative measurement and correction rather than relying on one-way TDOA evaluation.
Data Source
Figure 1~2
AI summary
The invention relates to a wave-based method in which at least two reference stations (1, 2) transmit signals (s1, s2; s3, s4 ), wherein the signals are transmitted almost at the same time (S1, S2), are transmitted in the same frequency range, are separable using a multiplexing method, wherein at least one of the sending reference stations (1, 2), besides transmitting its own signal (s1, s2), also receives at least one signal (s2, s1) sent by another reference station (2, 1) at the same time and determines a time stagger ( τ1 ) and/or a phase angle between its own transmission and the reception with high precision and wherein at least one receiving station (7) which at least receives the signals (s1, s2) receives the signals (s3, s4) from at least two of the reference stations (1, 2). Furthermore, the invention relates to a system and stations for performing the method.