Distance Measuring Apparatus Delay Time Compensation
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Solution Overview
Problem
Existing distance measuring apparatuses face errors due to delay times in amplifiers and multiple circuits, which are not effectively corrected, leading to inaccuracies in measurement time periods.
Innovation Solution
The apparatus includes an irradiator, first and second detectors, a simulation signal generator, and subtractors to measure emission and incidence times, with error correction by subtracting the difference between delay times of measurement circuits, providing an offset measurement time period for accurate distance calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a simulation signal is input to both the compensation time measuring circuit and the ranging time measuring circuit, then the delay times of both circuits can be measured and corrected, but this requires additional circuit complexity and measurement steps
Solution Approach 1:
The patent applies preliminary action by measuring the delay times of the compensation time measuring circuit and ranging time measuring circuit in advance using a simulation signal before actual distance measurement. The measured delay times are stored and used for correction during normal operation, eliminating the need for continuous complex correction mechanisms while maintaining high measurement precision.
2Measurement precision
If delay time correction is performed by measuring with actual detection circuits, then correction accuracy is improved, but measurement time increases due to additional measurement steps
Solution Approach 1:
The delay time measurement is performed as a preliminary step during device initialization or calibration phase, separate from the actual distance measurement process. This allows accurate delay characterization to be completed once, and the results reused for multiple distance measurements, minimizing time loss in operational measurements.
Solution Approach 2:
The patent uses a simulation signal that copies the characteristics of actual detection signals to measure delay times. This simulation approach provides accurate delay measurement without requiring actual target detection, separating the calibration process from operational measurement and reducing overall measurement time.
3Measurement precision
If ambient temperature variations are not compensated, then device simplicity is maintained, but measurement accuracy deteriorates due to temperature-induced delay changes
Solution Approach 1:
The patent implements feedback by measuring the delay times at different ambient temperatures and using this information to correct measurements. The system adapts to temperature variations by applying correction factors based on previously measured delay characteristics, maintaining accuracy without requiring complex real-time temperature control mechanisms.
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 solution corrects measurement time period errors, ensuring accurate distance measurement even with varying ambient temperatures, making it suitable for use on vehicles and other applications requiring precise distance sensing.
Implementation Method 1
a simulation signal generator (106) which generates a simulation signal, the simulation signal being simulated waveforms of output signals of the first detector (104) and the second detector (105)
Implementation Method 2
a compensation time measuring circuit (108) which measures a time at which the simulation signal is received to obtain a first time, and measures a time at which an output signal from the first detector (104) is received to obtain an emission time
Implementation Method 3
a first subtractor (111) which subtracts the emission time from the incidence time to obtain a measurement time period, and subtracts the first time from the second time to obtain an error time period
Data Source
AI summary
According to an embodiment, a distance measuring apparatus includes an irradiator that emits an irradiation wave to a measuring target, a first detector that directly detects the irradiation wave, a second detector that detects a reflection wave, a simulation signal generator that generates a simulation signal, a first meter that measures a first time and an emission time of the irradiation wave, a second meter that measures a second time and an incidence time of the reflection wave, a first subtractor that subtracts the emission time from the incidence time to obtain a measurement time period, and that subtracts the first time from the second time to obtain an error time period and a second subtractor that subtracts the error time period from the measurement time period to obtain an offset measurement time period.