Distance Measurement Device Randomized Pulse Timing
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Solution Overview
Problem
Conventional distance measurement devices face interference issues when multiple devices are present in the same environment, leading to inaccurate measurements due to electromagnetic wave interference, and existing solutions using pseudorandom codes require a large number of bits, increasing measurement time.
Innovation Solution
A distance measurement device that employs a pulse light emitter and optical sensor, with a controller setting random delay times for light emission based on a pseudorandom code, reducing interference by using a unique code sequence for each measurement and allowing for faster pulse light emission without waiting for roundtrip times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pseudorandom code is used to reduce interference between multiple distance measurement devices, then interference immunity is improved, but the number of pulses emitted increases and measurement time becomes longer
Solution Approach 1:
The patent applies dynamics by making the light emission timing variable and random rather than fixed. The controller sets light emission timing in each of N periods selected randomly from continuous K periods to a timing delayed by a random first time from the start time of the period. This dynamic randomization allows the system to maintain interference immunity while reducing the number of pulses needed, thus shortening measurement time.
2Reliability
If the number of pulses is increased to improve interference immunity using pseudorandom code, then interference reduction is achieved, but the complexity of the emission pattern increases
Solution Approach 1:
The patent applies partial action by using only N periods selected randomly from continuous K periods (where N < K) to generate the pseudorandom code pattern. This partial usage reduces the complexity of the emission pattern compared to using all K periods, while still achieving sufficient interference reduction. The random selection of N periods from K creates a manageable pattern that balances interference immunity with simplicity.
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
The solution provides enhanced interference immunity and reduces measurement time by using random delay times and pseudorandom codes, ensuring accurate distance measurements in multi-device environments.
Implementation Method 1
distance measurement devices that measure the distance to a measurement target by measuring the time from when electromagnetic waves are transmitted to when the electromagnetic waves are reflected by the target and received are conventionally known. As an example, there is the time of flight (TOF) method of measuring the distance to an object by emitting light from the vicinity of a distance measurement device to an object, and measuring the time until reflected light reflected by the object returns to the distance measurement device.
Implementation Method 2
an optical sensor that receives reflected light which is the pulse light reflected by the measurement target
Data Source
AI summary
A distance measurement device includes: a pulse light emitter that emits pulse light to a measurement target; an optical sensor that receives reflected light which is the pulse light reflected by the measurement target; and a controller that controls a light emission timing of the pulse light emitted by the pulse light emitter, and determines a distance to the measurement target, from a light reception timing of the reflected light detected by the optical sensor. The controller sets the light emission timing in each of N periods (N being a natural number less than K) selected randomly from continuous K periods (K being a natural number greater than or equal to 2) to a timing that is delayed by a random first time from a start time of the period.