TDOA Ultrasonic Locationing via Inferred Transmit Timer Values
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Solution Overview
Problem
TDOA-based ultrasonic locationing systems require more transmitters and incur higher computational burdens compared to TOA/TOF-based systems, making it challenging to rapidly and accurately locate and track mobile devices in real-time.
Innovation Solution
Inferring transmit timer values in a TDOA-based ultrasonic locationing system by selecting sets of possible transmit timer values, processing them to discard sets with fewer intersection points, and determining the centroid to minimize the triangular area created by intersection points, thereby reducing the number of transmitters and computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If TDOA-based ultrasonic locationing system is used, then synchronization between transmit and receive timer values is not required, but the number of transmitters increases and computational burden increases
Solution Approach 1:
The system performs preliminary actions by pre-calculating and storing timer offset values in a lookup table during system setup. These offset values are determined in advance based on the known geometric relationships between transmitters and receiver. During operation, the system simply retrieves the appropriate offset from the pre-computed table rather than performing complex real-time calculations, thereby reducing the number of transmitters needed while maintaining accuracy.
Solution Approach 2:
The system performs preliminary actions by pre-computing position solutions for multiple candidate transmit timer values and storing these in a lookup table. When a ranging signal is received, the system quickly searches the pre-computed table for matching position data rather than solving complex equations in real-time. This approach reduces computational burden and enables faster location determination with fewer transmitters.
2Ease of operation
If TDOA-based ultrasonic locationing system is used, then synchronization between transmit and receive timer values is not required, but computational complexity and processing time increase
Solution Approach 1:
The system performs preliminary actions by pre-calculating and storing timer offset values in a lookup table during system setup. These offset values are determined in advance based on the known geometric relationships between transmitters and receiver. During operation, the system simply retrieves the appropriate offset from the pre-computed table rather than performing complex real-time calculations, thereby reducing the number of transmitters needed while maintaining accuracy.
Solution Approach 2:
The system creates simplified copies of the complex TDOA calculation process by pre-computing position solutions for multiple candidate transmit timer values and storing these in a lookup table. Instead of solving complex hyperboloid intersection equations in real-time, the system copies and stores the results of these calculations in advance, then quickly retrieves the appropriate pre-computed solution during operation. This copying approach dramatically reduces processing time while maintaining location accuracy.
3Measurement precision
If more transmitters are deployed in TDOA-based system, then location accuracy improves, but system cost and complexity increase
Solution Approach 1:
The system performs preliminary actions by pre-calculating and storing timer offset values in a lookup table during system setup. These offset values are determined in advance based on the known geometric relationships between transmitters and receiver. During operation, the system simply retrieves the appropriate offset from the pre-computed table rather than performing complex real-time calculations, thereby reducing the number of transmitters needed while maintaining accuracy.
Solution Approach 2:
The system creates simplified copies of the complex TDOA calculation process by pre-computing position solutions for multiple candidate transmit timer values and storing these in a lookup table. Instead of solving complex hyperboloid intersection equations in real-time, the system copies and stores the results of these calculations in advance, then quickly retrieves the appropriate pre-computed solution during operation. This copying approach dramatically reduces processing time while maintaining location accuracy.
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 rapid and accurate determination of the mobile device's position, reducing the need for complex equations and intensive computations, and enabling more efficient operation of the TDOA-based locationing system.
Implementation Method 1
transmitting ultrasonic ranging signals in a time difference of arrival (TDOA)-based ultrasonic locationing system
Implementation Method 2
an ultrasonic receiver on the mobile device... each ultrasonic transmitter being operative, in its turn, for periodically transmitting ultrasonic ranging signals... to an ultrasonic receiver subsystem having a receiver, e.g., a microphone, mounted on, and jointly movable with, the mobile device
Data Source
AI summary
Ultrasonic transmitters periodically transmit ranging signals at unknown transmit timer values, and an ultrasonic receiver receives the ranging signals at known receive timer values on a mobile device in a venue in which a time difference of arrival (TDOA)-based ultrasonic locationing system is deployed. A controller infers the transmit timer values, and determines a current, real-time position of the mobile device based on flight time differences between the transmit timer values inferred by the controller and the known receive timer values.