Hybrid IR-US RTLS Using Time-of-Flight for 3D Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional real-time location systems (RTLS) face challenges in accurately locating assets using radio frequency (RF) and infrared (IR) or ultrasonic (US) signals, as they often require complex setups and may not efficiently determine distances and positions in three-dimensional spaces.
Innovation Solution
The system employs IR for ID communications and US for distance measurement, using the time difference between the arrival of IR and US signals to calculate distances, allowing for accurate location determination. This involves using multiple ultrasonic transducers to create virtual walls and determine positions in two or three-dimensional spaces, with the option to perform calculations at the tag or a network server.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional RF or IR/US RTLS systems are used, then location determination is possible, but measurement precision and accuracy in three-dimensional spaces deteriorates
Solution Approach 1:
The patent combines IR and US technologies into a hybrid RTLS system where IR transmitters provide timing references and US transducers perform distance measurements. This merging allows the system to achieve accurate three-dimensional location determination by leveraging the complementary strengths of both technologies without requiring completely separate systems.
Solution Approach 2:
The base stations in the hybrid system perform multiple functions: they transmit IR signals for timing synchronization and simultaneously support US transducers for distance measurement. This multi-functionality reduces overall system complexity by consolidating capabilities that would otherwise require separate dedicated components.
2Measurement precision
If multiple US transducers are used to determine positions in three-dimensional spaces, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent utilizes the time dimension by measuring the time of flight of US signals to determine distance. By combining temporal measurements (time of flight) with spatial arrangements of transducers, the system achieves three-dimensional positioning without requiring an excessive number of physical transducers, thus managing complexity while maintaining precision.
3Measurement precision
If IR signals are used for ID communications and US signals for distance measurement, then measurement precision improves, but use of energy increases
Solution Approach 1:
The IR transmitters send periodic beacon signals rather than continuous transmissions. This periodic operation allows the system to maintain measurement capability while significantly reducing energy consumption compared to continuous transmission, as the receivers only need to be active during these periodic intervals to capture timing information.
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 simplifies the RTLS setup, enhances accuracy in asset location, and allows for efficient use of resources by reducing power consumption and increasing the system's ability to function in non-line-of-sight conditions, while maintaining high precision and efficiency.
Implementation Method 1
an IR transmitter (e.g., a base station) transmits a periodic IR beacon
Implementation Method 2
IR signals propagate at the speed of light, and thus, the time they take to propagate from the emitter to the tag's IR receiver is essentially zero
Implementation Method 3
the time-of-arrival of the US signal, which propagates at a speed of about 300 meters/second in air
Implementation Method 4
US, which propagates at 300 meters per second
Implementation Method 5
the tag can measure the respective time-of-flight of each of the US transmissions from the US transmitters to the tag and compute the distance from the base-station
Data Source
AI summary
A hybrid infrared-ultrasound real time location system includes at least one emitter having an infrared transmitter and a plurality of ultrasound transmitters and at least one tag. The tag receives an infrared signal from the infrared transmitter and ultrasound signals from the ultrasound transmitters. The time between the time-of-arrival of the IR signal and the time-of-arrival of each ultrasound signal is calculated and used to measure the respective time-of-flight of each of the US transmissions from the US transmitters to the tag and compute location.