Sensor Array Frequency Control for Interference Mitigation
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Solution Overview
Problem
Existing door/gate monitoring devices using TOF sensors face interference issues due to mutual influence from sensor devices operating at the same frequency, leading to incorrect distance measurements and potential faults in operation.
Innovation Solution
Implementing a control device that allows sensor devices to operate at different frequencies, either modulation or carrier frequencies, to prevent measurement overlays, with the ability to dynamically change frequencies during measurements to avoid interference, and using multiple light sources or adjusting oscillators to ensure interference-free operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple sensor devices operate at the same frequency, then the device complexity is reduced and installation is easier, but measurement precision deteriorates due to mutual interference and overlay effects
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the modulation frequency of sensor devices. When interference is detected between multiple sensor devices, the control device changes the modulation frequency parameter to eliminate overlay effects, thereby maintaining measurement precision while allowing multiple devices to operate simultaneously
Solution Approach 2:
The patent implements dynamics by making the modulation frequency adjustable and changeable during operation. The control device can dynamically select different modulation frequencies based on detection results, transforming the static frequency configuration into a dynamic adaptive system that prevents interference while simplifying installation
2Manufacturing precision
If sensor devices use fixed frequencies during manufacture, then manufacturing precision is improved, but adaptability deteriorates when installation conditions require frequency adjustment to avoid interference
Solution Approach 1:
The patent applies preliminary action by equipping sensor devices with multiple light sources operating at different modulation frequencies during manufacture. This preliminary preparation allows the devices to adapt to various installation conditions without requiring complex post-manufacturing modifications, thus maintaining manufacturing precision while enabling frequency flexibility
Solution Approach 2:
The patent implements universality by designing sensor devices that can operate at multiple modulation frequencies. The control device selects appropriate frequencies based on installation conditions and interference detection, making the sensor device universally applicable to different scenarios without requiring custom manufacturing for each case
3Productivity
If sensor devices operate simultaneously at the same frequency, then productivity is improved by parallel operation, but reliability deteriorates due to measurement errors from mutual interference
Solution Approach 1:
The patent applies periodic action by implementing time-division multiplexing where sensor devices operate in alternating periods at the same frequency. When one device is active, others are inactive, eliminating mutual interference while maintaining high productivity through rapid switching between devices
Solution Approach 2:
The patent uses parameter changes by dynamically adjusting modulation frequencies when simultaneous operation is required. The control device detects interference and assigns different frequencies to conflicting sensor devices, enabling reliable parallel operation without sacrificing productivity
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 accurate distance measurements by preventing sensor interference, allowing multiple sensor devices to operate without measurement errors, and allowing for flexible configuration and adjustment during installation to optimize frequency usage.
Implementation Method 1
TOF sensors (Time of Flight sensors) emit light and use the reflected light to determine the distance that the light has traveled from a reflective surface back to the sensor. This can be done, for example, by measuring the time that a light pulse needs from a source via a reflective surface back to the sensor.
Implementation Method 2
Another possibility is to modulate an oscillation onto the light and to compare the phase of the oscillation of light reflected back with the phase of emitted light. Knowing the modulation frequency, the length of the light path can be determined from the phase difference.
Implementation Method 3
emit electromagnetic radiation source and to evaluate the electromagnetic radiation emitted by the source and reflected by a reflective surface of an object
Data Source
Figure 1~2
Figure 3
AI summary
Disclosed is a sensor array comprising several sensor devices, an electromagnetic radiation source, an electromagnetic radiation receiver, and a control device which is designed so as to emit electromagnetic radiation by means of the source and determine a distance that the electromagnetic radiation emitted by the source covers from a reflective surface of an object to the receiver by evaluating the reflected radiation. The inventive sensor devices of the several sensor devices operate at different frequencies or by time-division multiplexing. Also disclosed is a sensor device for a sensor array, the control device being designed so as to measure the distance at different frequencies or by time-division multiplexing.