Offset Transducer Distance Measurement for Variable Sound Speed
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Solution Overview
Problem
SONAR technology for measuring distances is unreliable in environments where the speed of sound varies significantly, such as when a mobile device travels through different media with unknown or varying sound speeds.
Innovation Solution
A system and method using physically offset transducers to measure distances, where two transducers transmit and receive sonic pulses in the same direction, with one transducer being physically offset from the other. The processor calculates the speed of sound and determines the distance to an object using the time-of-flight values from both transducers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single transducer is used for SONAR distance measurement, then the device complexity is low, but the measurement precision deteriorates when sound speed varies in different media
Solution Approach 1:
The system divides the measurement function into two separate transducers: one dedicated to transmitting sonic pulses and another dedicated to receiving echoes. This segmentation allows independent optimization of transmission and reception characteristics, improving measurement precision while maintaining manageable device complexity through functional specialization.
Solution Approach 2:
The patent introduces an intermediary processing system that receives signals from both transducers, calculates time-of-flight values, determines sound speed, and computes distance measurements. This intermediary processor acts as a mediator that resolves the complexity of variable sound speed conditions by performing centralized calculations based on differential time measurements from the two transducers.
2Device complexity
If the speed of sound is assumed constant for distance calculation, then the calculation process is simple, but the reliability deteriorates in environments with varying sound speeds
Solution Approach 1:
The system implements feedback by using the measured time-of-flight differences between the two transducers to continuously determine the actual sound speed in the current medium. This feedback mechanism allows the system to adapt to varying sound speeds in different environments (air, water, petroleum, natural gas) and maintain reliable distance measurements without requiring complex pre-programmed sound speed tables.
Solution Approach 2:
The patent dynamically changes the sound speed parameter based on environmental conditions by calculating it from the differential time-of-flight measurements. Instead of assuming a constant sound speed, the system allows the sound speed parameter to vary according to the actual medium conditions, thereby maintaining measurement reliability across diverse environments while keeping the calculation process relatively simple.
3Measurement precision
If physically offset transducers are used to compensate for sound speed variations, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent introduces a spatial dimension offset between the two transducers along the direction of motion. By positioning transducers at different locations separated by a known distance, the system creates a geometric configuration that enables sound speed determination through differential time-of-flight measurements, thereby improving measurement precision while adding only a simple spatial arrangement rather than complex instrumentation.
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 allows for accurate distance measurement in diverse environments by compensating for variations in sound speed, enabling effective control of mobile device movement.
Implementation Method 1
The first transducer is configured to transmit a first sonic pulse in a first direction towards an object, to receive a first echo of the first sonic pulse from the object
Implementation Method 2
The second transducer is configured to transmit a second sonic pulse in the first direction towards the object, to receive a second echo of the second sonic pulse from the object
Implementation Method 3
The processor includes code executed therein configured to receive the first time-of-flight value A and the second time-of-flight value B, to generate a speed-of-sound value S
Implementation Method 4
The processor can be configured to determine the speed-of-sound value S according to S=Δd/|A−B|, wherein the value |A−B| is the absolute value of a difference of the first time-of-flight value A and the second time-of-flight value B
Data Source
AI summary
A system and method measure distances using physically offset transducers. The system includes first and second transducers physically offset by a predetermined offset distance for generating time-of-flight values of sonic pulses from the transducers to an object. A processor determines a speed of sound in a medium from the time-of-flight values and the offset distance, and determines a distance of at least one of the transducers from the object using the speed of sound and a corresponding time-of-flight value. A controller generates a control signal from the determined distance to control movement of a mobile device. A method implements the system.