Transponder Delay Mechanism for Short-Range Radio Positioning
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Solution Overview
Problem
Existing distance measurement systems face challenges in achieving high accuracy over short distances, particularly in closed environments, due to the short transit time of radio signals and limitations in frequency bands, leading to difficulties in identifying the shortest path and precise delay settings.
Innovation Solution
A system that precisely delays the interrogation signal in the transponder using a quartz-precise clock and variable delay elements, allowing for picosecond-range precision, combined with a register chain and microcontroller control for binary search optimization, to accurately measure transit times and determine distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If time-of-flight measurement is used for short distance measurement, then measurement speed is improved, but measurement precision deteriorates due to extremely short transit times in the nanosecond range
Solution Approach 1:
The system performs preliminary actions by pre-synchronizing the transponder's internal clock with the interrogation station's clock before measurement, and by pre-configuring the variable delay element with initial delay values. This preparation ensures that when the actual measurement occurs, the timing references are already aligned, enabling precise measurement of extremely short transit times without requiring complex real-time synchronization during the measurement process itself.
Solution Approach 2:
The patent introduces an intermediary mechanism - a variable delay element with picosecond precision control - that acts as a mediator between the transmitted signal and the received echo. By inserting a controllable delay in the reference signal path, the system can extend the effective measurement window to match the extremely short transit time, making the measurement feasible and precise without directly measuring the nanosecond-range transit time itself.
2Measurement precision
If the transponder delays the response signal with high precision, then distance measurement accuracy is improved, but device complexity increases due to requirement of picosecond-range delay precision
Solution Approach 1:
The patent replaces mechanical or analog delay mechanisms with a digitally controlled variable delay element that achieves picosecond precision through electronic control. The delay is adjusted by a microcontroller based on binary search optimization, substituting complex hardware synchronization mechanisms with a simpler digital control approach that references the transponder's internal quartz clock, already synchronized with the interrogation station.
Solution Approach 2:
The transponder uses its own internal clock signal, already synchronized with the interrogation station, to control the delay element. This self-service approach eliminates the need for external reference signals or complex inter-device synchronization hardware, as the transponder autonomously generates the precise delay control signal from its own synchronized clock, reducing overall system complexity.
3Device complexity
If frequency domain measurement with limited frequency bands is used, then system simplicity is maintained, but measurement precision deteriorates due to inability to clearly identify the shortest path
Solution Approach 1:
Instead of trying to identify the shortest path by analyzing frequency domain characteristics within limited bands, the patent inverts the approach by using time domain measurement with a controlled delay mechanism. The system directly measures the transit time of the first arriving signal (shortest path) in the time domain, bypassing the frequency domain limitations and multipath identification problems entirely.
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
Enables reliable and precise distance measurement over short distances with improved accuracy and stability, overcoming previous limitations in time-of-flight measurements and frequency domain constraints.
Implementation Method 1
a quartz-precise clock and variable delay elements, allowing for picosecond-range precision
Implementation Method 2
the distance is calculated from the signal delay due to the constant speed of light
Data Source
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AI summary
The invention relates to a novel system for measuring short distances using the propagation time of radio, sound, or light signals between at least one request unit and a transponder. An interference with the response signal of the transponder due to the request signal is eliminated by means of a highly precise delay of the request in the transponder. The delay is implemented with the required degree of precision with crystal accuracy in that the delay is carried out in a digital or analog register line, the register clock of which is kept in phase synchronization with the request signal such that the request signal is variably delayed in the request unit, and the delay is adapted using the detectable jump of the total propagation time, i.e. round trip, by a register clock period at the synchronization time preferably using a binary search.