Ultrasonic Positioning System with Dynamic Buffer Adjustment
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Solution Overview
Problem
Ultrasonic positioning systems face challenges due to long reverberation and flight times of ultrasonic sound waves, leading to signal collisions and missed emissions, which result in low refresh rates and reduced positioning accuracy when multiple emitters are present.
Innovation Solution
The system measures and adjusts the reverberation and flight times for each emitter, calculating an adjusted buffer time period to optimize the timing of subsequent emissions, ensuring accurate and frequent positioning updates by avoiding signal collisions and accounting for environmental noise and emitter movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a buffer time period is used to prevent signal collisions, then signal reception reliability is improved, but the refresh rate of device position updates deteriorates
Solution Approach 1:
The system dynamically adjusts the buffer time period based on measured flight times and reverberation characteristics. Instead of using a fixed conservative buffer, the buffer is optimized in real-time to be just long enough to prevent signal collisions while minimizing idle time, thereby maintaining reliability while maximizing the refresh rate for multiple emitters.
Solution Approach 2:
The system changes the buffer time parameter adaptively by measuring actual flight times and reverberation durations. This allows the buffer to be tuned to the specific environmental conditions and emitter configurations, preventing signal collisions while enabling faster sequential emissions that improve positioning update rates.
2Reliability
If a long buffer time period is used to account for reverberation and flight time, then signal collision prevention is improved, but the number of emitters that can be tracked simultaneously deteriorates
Solution Approach 1:
The system implements dynamic buffer adjustment where the buffer duration is continuously optimized based on measured flight times and reverberation characteristics. This allows the system to maintain reliable signal separation while reducing the time cost per emitter, thereby enabling tracking of a larger number of emitters within the same time window.
Solution Approach 2:
By optimizing and minimizing the buffer time to only what is necessary for reliable signal separation, the system eliminates unnecessary idle time between emissions. This continuous optimization of the emission sequence allows more emitters to be tracked simultaneously without compromising signal collision prevention.
3Measurement precision
If sequential emission timing is used to avoid signal collisions, then reception accuracy is improved, but the system complexity increases due to timing coordination requirements
Solution Approach 1:
The system employs feedback mechanisms where flight times and reverberation characteristics are measured and used to adjust emission timing. This closed-loop approach maintains high reception accuracy by adapting to environmental conditions while automating the timing coordination, thereby reducing the operational complexity despite the sophisticated timing requirements.
Solution Approach 2:
The system performs self-calibration by automatically measuring flight times and reverberation durations and using this information to optimize emission timing. This self-adjusting capability maintains high reception accuracy without requiring manual intervention or complex external coordination, effectively managing system complexity through autonomous optimization.
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 significantly improves the refresh rate of emitter signals, increasing positioning accuracy up to sixteen times over prior art, enabling real-time tracking of multiple items and accommodating more emitters in the system.
Implementation Method 1
The ultrasonic emitter can transmit ultrasonic energy in a short burst which can be received by an ultrasonic transducer (microphone) in the ultrasonic receiver
Implementation Method 2
ultrasonic waves are typically subject to acoustic reverberation
Implementation Method 3
determining a maximum flight time for a signal from any emitter within the reading environment
Data Source
AI summary
Compensating reverberation and flight times in an ultrasonic positioning system includes establishing maximum flight and reverberation times for ultrasonic signals within an environment. These maximum times are added to define a maximum buffer time period. Ultrasonic signals are emitted sequentially from each of a plurality of emitters, where the ultrasonic signal from each emitter is separated in time by at least one maximum buffer time period. Afterwards, a reverberation and flight time for each ultrasonic signal is determined and then the flight time of the next subsequent emitter is subtracted to define an adjusted emit time for the emitter that emitted that ultrasonic signal. An emitting time for a next subsequent emitter as adjusted to maximize the refresh rate. Emitters are scheduled to emit such that the receiver is always receiving a signal or waiting for actual reverberation.