Wireless Ranging With Phase Shift and Time-of-Flight Fusion
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Solution Overview
Problem
Existing wireless devices, particularly battery-powered devices like keyfobs, face challenges in accurately measuring distance with minimal power consumption due to the need for multiple measurements across various frequencies, which can be time and energy intensive.
Innovation Solution
The method combines time-of-flight and phase shift measurements to determine distance between wireless devices, reducing the number of receiver/transmitter switches and power consumption by using phase-locked loops to generate RF signals and calculating distance based on both time and phase shift measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple measurements on multiple frequencies are performed to maximize distance measurement accuracy, then measurement precision is improved, but power consumption increases and measurement time increases
Solution Approach 1:
The patent combines time-of-flight measurement and phase shift measurement into a single integrated system. The time-of-flight component provides accurate distance measurements over longer ranges, while the phase shift component provides precise measurements over shorter ranges. By merging these two measurement methods and fusing their results, the system achieves high measurement precision across all distances without requiring multiple frequency measurements, thereby reducing power consumption.
Solution Approach 2:
The patent implements a universal distance measurement system that can operate effectively across all distance ranges using a single integrated approach. The system uses both time-of-flight and phase shift measurements simultaneously, allowing it to provide accurate measurements whether the target is near or far, eliminating the need for separate measurement procedures at different frequencies and reducing overall power requirements.
2Measurement precision
If multiple measurements on multiple frequencies are performed to maximize distance measurement accuracy, then measurement precision is improved, but measurement time increases
Solution Approach 1:
The patent merges time-of-flight measurement and phase shift measurement into a single simultaneous operation. Both measurement types are performed at the same time using the same RF signal, allowing the system to obtain accurate distance measurements without sequentially performing multiple frequency measurements. This significantly reduces measurement time while maintaining high precision through the complementary nature of the two measurement methods.
3Measurement precision
If receiver/transmitter switches are used for distance measurement, then measurement capability is achieved, but power consumption increases
Solution Approach 1:
The patent implements continuous RF signal transmission and reception without requiring repeated switching between transmission and reception modes. The system continuously monitors both time-of-flight and phase shift characteristics of the RF signal, eliminating the need for frequent receiver/transmitter switches. This continuous operation maintains measurement capability while significantly reducing power consumption by avoiding the energy-intensive switching operations.
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 enhances accuracy and reduces power requirements, enabling more precise distance measurements with fewer measurements, making it suitable for battery-powered devices.
Implementation Method 1
using phase-locked loops to generate RF signals
Implementation Method 2
calculating a first measurement of the distance based on a time between the first wireless device sending the first packet and receiving the second packet
Implementation Method 3
calculating a second measurement of the distance based on a phase shift of the first continuous wave signal and the second continuous wave signal
Data Source
AI summary
Systems and methods of measuring distance between two wireless devices by combining phase shift and time-of-flight measurements. A first wireless devices sends a first packet to the second wireless device. After receiving the first packet, the second wireless device sending to the first wireless device a second packet. After sending the second packet, the second wireless device sends a first continuous wave signal to the first wireless device. After receiving the first continuous wave signal, the first wireless device sends to the second wireless device a second continuous wave signal. The first wireless device then calculates a time-of-flight measurement based on a time between the first wireless device sending the first packet and receiving the second packet, and calculates a second measurement based on a phase shift of the first continuous wave signal and the second continuous wave signal, and combines the two measurements.