Ultrasound Transmitter Frequency Encoding for Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ultrasound-based systems for determining the position of mobile units in environments like hospitals face challenges with interference and accuracy as the number of mobile units increases, leading to decreased position update rates and interference issues, which are exacerbated by the need for expensive and power-hungry digital signal processing circuits.
Innovation Solution
A system that transmits ultrasonic signals encoding a binary identifier using pairs of frequencies at different time positions, allowing for robust decoding even in interference-prone environments by transmitting each bit twice, reducing the impact of frequency-specific interference and destructive interference, and enabling accurate position determination without the need for complex signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital signal processing circuits are used to cope with noise in ultrasound-based position determination systems, then noise resistance is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent applies preliminary action by pre-encoding position information into ultrasonic signals using frequency modulation before transmission. The mobile unit transmits encoded signals that contain position data, and fixed receivers decode these signals to determine position. This approach eliminates the need for complex digital signal processing circuits at the receiving end, as the position information is embedded in the signal structure itself through frequency encoding, thereby reducing device complexity and power consumption while maintaining noise resistance
Solution Approach 2:
The patent replaces complex digital signal processing mechanical/electronic systems with a simpler frequency-based encoding and decoding mechanism. Instead of using DSP circuits to extract position information from noisy ultrasound signals, the system uses predetermined frequency relationships where position is directly encoded in the frequency domain. This substitution simplifies the hardware requirements while maintaining reliability in noisy environments
2Adaptability or versatility
If the number of mobile transmitter units in the system increases, then system coverage and positioning capability are improved, but the average rate of position updates for each transmitter unit decreases
Solution Approach 1:
The patent implements periodic action by having mobile transmitter units send ultrasonic position signals at regular, predetermined time intervals rather than continuously or on-demand. Each mobile unit transmits encoded position information periodically, and fixed receivers process these periodic signals to track position. This periodic transmission scheme allows multiple mobile units to coexist in the system without excessive interference, as the time-division nature of periodic transmissions ensures that not all units transmit simultaneously, thereby maintaining position update rates even as system coverage expands with more mobile units
Solution Approach 2:
The system uses preliminary action by pre-coordinating transmission schedules and frequency assignments for multiple mobile units before they operate in the system. Each mobile unit is assigned specific frequency channels and transmission timing in advance, allowing them to operate simultaneously without conflict. This pre-planned coordination enables the system to scale to multiple mobile units while maintaining high position update rates, as units don't need to wait for silence periods - their transmissions are scheduled to avoid interference
3Productivity
If mobile transmitter units transmit simultaneously to improve position update rates, then productivity is improved, but interference between units occurs
Solution Approach 1:
The patent applies local quality by assigning different frequency characteristics to different mobile units or different position signals. Each mobile transmitter unit uses specific frequency ranges or frequency modulation patterns that are locally optimized for its operation. This frequency differentiation allows simultaneous transmissions from multiple units to be distinguished at the receiver, reducing interference while maintaining high position update rates. The local quality principle ensures that each unit's signal has unique spectral characteristics that prevent confusion with other units' signals
Solution Approach 2:
The patent implements segmentation by dividing the ultrasonic frequency spectrum into multiple channels or bands, with each mobile transmitter unit assigned to specific frequency segments. This frequency-division approach allows multiple units to transmit simultaneously on different frequency segments without interfering with each other. The segmentation of the frequency resource enables the system to achieve high position update rates from multiple concurrent transmitters while eliminating signal interference through spectral separation
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 system provides reliable and accurate position determination of mobile units with reduced power consumption and increased update rates, as it can differentiate between multiple transmitter stations and mitigate interference effects, allowing for indefinite growth in the number of mobile units without compromising accuracy.
Implementation Method 1
a transmitter device arranged to transmit an ultrasonic signal that encodes a binary identifier
Implementation Method 2
the encoding is such that each bit position in the identifier is associated with a respective pair of frequencies and with respective first and second time positions in the signal, with the value of the bit position in the identifier determining which frequency of the pair of frequencies is transmitted at the first respective time position in the signal
Implementation Method 3
a receiver device arranged to receive the ultrasonic signal
Implementation Method 4
decoding means configured to decode the binary identifier from the received signal by determining a value for each bit position in the identifier using information relating to the strength of the received signal at (a) the first frequency and first time position in the received signal that are associated with the bit position
Data Source
AI summary
An ultrasonic transmitter apparatus is configured to transmit an ultrasonic signal that communicates a binary identifier. The apparatus includes an ultrasound transmission system and is configured to transmit an ultrasonic signal that communicates the binary identifier according to an encoding in which each bit position in the binary identifier is associated with a respective pair of frequencies and with respective first and second time positions in the ultrasonic signal. The value of the bit position in the binary identifier determines which frequency of the pair of frequencies is transmitted at the first respective time position in the ultrasonic signal, with the other frequency of the pair of frequencies being transmitted at the second respective time position in the ultrasonic signal.