RSSI and Time-of-Flight Distance Measurement Apparatus
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Solution Overview
Problem
Existing methods for determining the distance between a transmitter and a receiver using signal strength indicator (RSSI) values are inaccurate due to channel-dependent attenuation, especially in mobile devices, and time-of-flight measurements are limited to a small range.
Innovation Solution
An apparatus that measures both RSSI and time-of-flight values, using these to improve distance determination by comparing them with stored pairs and establishing a transmitter-specific probabilistic relationship, allowing for accurate distance estimation over a wider range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only RSSI value is used to determine distance, then the measurement can be performed over a wide range, but the accuracy deteriorates due to channel-dependent attenuation
Solution Approach 1:
The patent combines RSSI value measurement and time-of-flight measurement into a single apparatus that processes both measurement types. The processing unit integrates these two different measurement approaches to determine distance, using the time-of-flight value as a correction factor for the RSSI-based distance estimation, thereby improving accuracy while maintaining operational simplicity.
2Measurement precision
If only time-of-flight measurement is used to determine distance, then the accuracy is improved, but the measurement range deteriorates to a small range of up to 20 m
Solution Approach 1:
The patent merges time-of-flight measurement capability with RSSI measurement capability in one apparatus. The processing unit combines the accurate but short-range time-of-flight measurements with the longer-range RSSI-based measurements, using time-of-flight as a correction factor to extend the effective measurement range while maintaining high accuracy.
3Length of moving object
If RSSI value is used for distance estimation, then the measurement can cover large distances, but the reliability deteriorates due to user behavior and environmental conditions
Solution Approach 1:
The patent implements a feedback mechanism where the time-of-flight measurement continuously corrects the RSSI-based distance estimation. The processing unit uses the time-of-flight value as a correction factor that compensates for channel-dependent attenuation and user behavior variations, thereby improving the reliability of distance measurement over large ranges.
4Measurement precision
If multiple measurements are performed to improve accuracy, then the distance determination accuracy is improved, but the measurement time increases
Solution Approach 1:
The patent merges multiple measurement types (RSSI and time-of-flight) into a single integrated measurement process. The processing unit simultaneously processes both measurement values and compares them against stored reference pairs in one operation, achieving high accuracy without requiring sequential multiple measurements that would increase time loss.
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
The combination of RSSI and time-of-flight values enables accurate distance determination, correcting for channel-dependent attenuation and extending the measurement range from 20 m to up to 100 m, with continuous adjustment for changing transmitter characteristics.
Implementation Method 1
a time-of-flight (ToF) value of the radio channel. The time-of-flight measurement measures the time interval between the transmission and the reception of a signal
Data Source
AI summary
An apparatus for determining the distance from a transmitter to a receiver is proposed, wherein the transmitter and the receiver are configured to communicate via a radio channel. The apparatus comprises at least one measuring unit configured to measure a received signal strength indicator value and a time-of-flight value of the radio channel. The apparatus further comprises a processing unit configured to compare the measured pair of the received signal strength indicator value and the time-of-flight value with stored pairs of received signal strength indicator values and time-of-flight values, wherein the stored pairs of received signal strength indicator values and time-of-flight values are each associated with a distance of the transmitter to the receiver, and wherein the processing unit is configured to determine the distance of the transmitter to the receiver based on the comparison result.