Ultrasonic Phase Difference Array Indoor Positioning
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Solution Overview
Problem
Current position determination systems, such as GPS, struggle to provide accurate location data within enclosed spaces like buildings due to limitations in urban areas and indoor environments, necessitating the development of effective indoor positioning systems (IPS) that can seamlessly integrate with GPS technology.
Innovation Solution
An ultrasonic-based system that emits and detects acoustic pulses at multiple locations to calculate the phase difference, allowing for precise three-dimensional positioning of mobile electronic devices within enclosed spaces by using a ceiling-located base station with multiple receivers and transmitters, which determines the relative position based on range and phase differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If GPS technology is used for position determination, then global coverage and simplicity are achieved, but accuracy in enclosed spaces and urban areas deteriorates
Solution Approach 1:
The system segments the positioning function into two parts: GPS for outdoor/global positioning and ultrasonic phase difference array for indoor/enclosed space positioning. This allows each subsystem to operate optimally in its designated environment, with the indoor system activating when GPS signal availability deteriorates.
Solution Approach 2:
The ultrasonic phase difference array system acts as an intermediary positioning system that bridges the gap where GPS fails. It provides continuous positioning capability in enclosed spaces by using acoustic wave propagation through air, complementing the electromagnetic wave-based GPS system.
2Measurement precision
If ultrasonic phase difference array system is implemented, then positioning accuracy in enclosed spaces is improved, but system complexity increases
Solution Approach 1:
The base station performs multiple functions: transmitting ultrasonic signals for positioning, receiving signals from multiple directions, calculating phase differences, and determining three-dimensional positions. This multi-functionality reduces the need for separate specialized devices and simplifies the overall system architecture.
Solution Approach 2:
The system uses the mobile device's own speaker to transmit the ultrasonic test signal, eliminating the need for a separate transmitter in the mobile device. The mobile device serves itself as both transmitter and receiver, reducing hardware complexity.
3Measurement precision
If multiple receivers are used to detect phase differences, then positioning precision is improved, but device size and cost increase
Solution Approach 1:
The system transitions from two-dimensional positioning (horizontal plane only) to three-dimensional positioning by adding vertical dimension capability. The omnidirectional microphone array detects phase differences from multiple directions including elevation angles, enabling accurate 3D position calculation without proportionally increasing receiver count.
Solution Approach 2:
The system performs preliminary calibration by moving the mobile device to known reference positions and storing the corresponding phase difference data. This pre-established reference information accelerates subsequent positioning calculations and reduces real-time computational complexity.
4Reliability
If omnidirectional sensitivity is achieved, then coverage and reliability are improved, but antenna/array complexity increases
Solution Approach 1:
The system uses periodic ultrasonic test signals transmitted at regular intervals to maintain continuous positioning capability. This periodic transmission ensures reliable detection even in the presence of environmental noise and maintains synchronization between transmitter and receiver systems.
Solution Approach 2:
The system dynamically adjusts the ultrasonic signal frequency based on environmental conditions and positioning requirements. This dynamic frequency adjustment optimizes signal propagation characteristics and maintains reliable detection across different enclosed space environments.
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 system achieves high accuracy in positioning mobile devices to a few centimeters in three dimensions, overcoming the limitations of existing technologies by using a compact base station with omni-directional sensitivity and robust algorithms to handle multiple-path sound reflections.
Implementation Method 1
emitting an acoustic pulse from the position of the mobile electronic device
Implementation Method 2
The acoustic pulse is detected at a known position at three spaced apart locations along each of at least two lines extending in different directions
Implementation Method 3
A phase difference of the acoustic pulse between each of the detecting locations is determined. The relative position of the device with respect to the known position is obtained from the range and phase differences.
Data Source
AI summary
A method for determining position of a mobile electronic device includes emitting an acoustic pulse from the position of the mobile electronic device. The acoustic pulse is detected at a known position at three spaced apart locations along each of at least two lines extending in different directions. The range and phase difference of the acoustic pulse between each of the detecting locations is determined. A relative position of the device with respect to the known position is obtained from the range and phase differences.