Multi-Frequency Sonar Detection for Complex-Object Interference
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Solution Overview
Problem
Sonar apparatuses face interference issues when detecting objects with complex shapes due to multiple reflections of ultrasonic signals, leading to reduced received power, especially when signals overlap with different path lengths.
Innovation Solution
The sonar apparatus transmits and receives ultrasonic signals at multiple frequencies, specifically choosing frequencies such that the combined power of the composite signal is greater than the power of each individual signal, thereby reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If ultrasonic signals are transmitted and received at a single frequency, then the device complexity is low, but the received power is reduced due to signal interference when detecting complex objects
Solution Approach 1:
The patent changes the frequency parameter of the transmitted ultrasonic signals by using multiple frequencies (e.g., first frequency f1 and second frequency f2) instead of a single frequency. This parameter change allows the system to avoid interference patterns that occur at specific frequencies, thereby increasing the received power when detecting complex objects with multiple reflection points.
2Measurement precision
If multiple frequencies are used to increase received power, then the detection accuracy improves, but the use of energy increases
Solution Approach 1:
The patent employs periodic transmission of ultrasonic signals at different frequencies in a time-multiplexed manner. The transmission circuit alternates between transmitting at the first frequency f1 and the second frequency f2, rather than transmitting all frequencies simultaneously. This periodic action reduces the total energy consumption compared to simultaneous multi-frequency transmission, while still achieving improved detection accuracy through frequency diversity.
3Loss of information
If ultrasonic signals reflect at multiple points on complex objects, then more information about the object is obtained, but signal interference occurs reducing the received power
Solution Approach 1:
The patent changes the frequency parameter to resolve interference caused by multiple reflection paths. By transmitting at multiple frequencies (f1 and f2) and selecting the frequency that yields higher received power, the system maintains information from multiple reflection points while avoiding destructive interference that would reduce the overall received power.
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 received power of ultrasonic signals, allowing for effective detection of complex objects by ensuring at least one frequency's composite signal has stronger power, thus improving detection accuracy.
Implementation Method 1
Sonar apparatuses can detect the presence of objects by transmitting ultrasonic signals and receiving ultrasonic signals reflected by objects
Implementation Method 2
When ultrasonic signals are received more than once, there is a possibility that the ultrasonic signals interfere with each other and the received power of the combined ultrasonic signal is reduced
Data Source
AI summary
A sonar apparatus includes: a transmission circuit that transmits transmission signals of a plurality of frequencies; a reception circuit that receives reception signals corresponding to the transmission signals of the plurality of frequencies; and a detection circuit that detects an object based on the reception signals, in which the plurality of frequencies is determined such that a power of a composite signal of reception signals of at least one frequency of the plurality of frequencies is greater than a power of each reception signal making up the composite signal.