Time-of-flight Distance Measurement Unambiguous Range
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Solution Overview
Problem
Distance measurement methods using transit time face ambiguity issues, leading to incorrect detection of objects outside the unambiguous range being incorrectly identified within the safety area, which can cause unnecessary system shutdowns.
Innovation Solution
The method involves irradiating a target object with an electromagnetic reference signal, determining the phase difference and signal strength, and comparing the signal strength with a threshold value to determine if the object is within the unambiguous range, thereby avoiding incorrect detections by ensuring the object is either inside or outside the unambiguous area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If transit time measurement is used for distance determination, then measurement speed is improved, but measurement ambiguity occurs for objects outside the unambiguous range
Solution Approach 1:
The patent adds a second dimension of discrimination by introducing signal strength evaluation alongside phase difference measurement. While phase difference provides distance information modulo 360°, the signal strength parameter provides an additional degree of freedom to distinguish between objects within and outside the unambiguous range, enabling unambiguous distance determination beyond the traditional limitation.
Solution Approach 2:
The patent changes the measurement approach by evaluating multiple parameters (phase difference and signal strength) instead of relying solely on phase difference. By comparing signal strength against a predetermined threshold, the system can determine whether an object is within or outside the unambiguous range, resolving the measurement ambiguity without sacrificing speed.
2Area of stationary object
If the unambiguous range is extended, then detection coverage is improved, but false detection of objects outside the safety area increases
Solution Approach 1:
The patent segments the detection space into two distinct regions: objects within the unambiguous range (where phase difference alone suffices for accurate measurement) and objects outside the unambiguous range (where signal strength thresholding is required). This segmentation allows the system to maintain high detection accuracy across extended coverage areas by applying appropriate evaluation criteria to each region.
Solution Approach 2:
The patent introduces signal strength as an intermediary parameter that mediates between the phase difference measurement and the final distance determination. This intermediary enables the system to extend detection coverage while maintaining reliability by using signal strength as a filter to identify and exclude false detections of objects outside the unambiguous range.
3Loss of time
If phase difference measurement is used, then response time is reduced, but incorrect detection of objects outside safety area occurs
Solution Approach 1:
The patent maintains continuous and rapid response by evaluating both phase difference and signal strength simultaneously rather than sequentially. The dual-parameter evaluation is performed in parallel during the same measurement cycle, ensuring that the system responds quickly to objects within the unambiguous range while also filtering out false alarms from objects outside the range, thus maintaining fast response time without increasing false alarm rate.
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 of distance measurement by clearly differentiating between objects within and outside the unambiguous range, reducing false alarms and increasing system availability by preventing unnecessary shutdowns.
Implementation Method 1
receiving a portion of the reference signal reflected by the target object as a measurement signal
Data Source
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AI summary
A method for determining the distance to a target object by means of a time-of-flight measurement comprises irradiating the target object with an electromagnetic reference signal, receiving a portion of the reference signal reflected by the target object as a measurement signal, determining a phase difference between the reference signal and the measurement signal, and deriving distance information from the phase difference. Furthermore, the method includes determining the strength of the measurement signal and comparing the strength of the measurement signal with a predetermined threshold value to determine whether the target object is located within a uniqueness range of the time-of-flight measurement.