Distance Measurement System Using ID Signal Modulation for Interference Rejection
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Solution Overview
Problem
Distance measurement systems in close proximity can experience decreased accuracy due to interference waves in the same frequency band, leading to incorrect phase detection and unreliable distance calculations, particularly in smart key systems vulnerable to relay attacks.
Innovation Solution
Incorporating ID information into the distance measurement signal, which is modulated and demodulated to detect interference waves, allowing the system to discard affected signals and ensure accurate distance measurements by only using valid phase detection results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple distance measurement systems operate in the same frequency band, then the coverage and functionality of the system is improved, but interference waves cause phase detection errors and decrease measurement accuracy
Solution Approach 1:
The system transmits ID information modulated onto the distance measurement signal and receives the modulated signal back. By demodulating and comparing the received ID information with the transmitted ID information, the system obtains feedback to determine whether interference waves are present. This feedback mechanism allows the system to identify and discard measurements affected by interference, resolving the contradiction between system coverage and measurement accuracy.
Solution Approach 2:
ID information serves as an intermediary element that is modulated onto the distance measurement signal. This intermediary carries identification data that enables the receiving system to verify signal integrity and detect interference waves. The ID information acts as a mediator between the transmitted and received signals, allowing the system to distinguish valid signals from interfered signals and maintain accurate distance measurements even in environments with multiple operating systems.
2Productivity
If phase detection is performed without interference verification, then the distance measurement process is simple and fast, but interference waves cause incorrect phase detection and unreliable results
Solution Approach 1:
The system performs preliminary verification by transmitting and receiving ID information before finalizing the distance measurement. The control circuit demodulates the received signal to extract ID information and compares it with the transmitted ID information to determine the presence of interference waves. This preliminary action ensures that only reliable measurements are accepted, improving measurement reliability without significantly impacting the overall process speed.
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
Prevents interference-induced errors in distance measurement calculations, maintaining accuracy even in environments with multiple distance measurement systems operating in the same frequency band, thereby enhancing security against relay attacks.
Implementation Method 1
a modulation circuit for generating the distance measurement signal including a modulated signal obtained by modulating an identification signal
Implementation Method 2
calculating a distance between the devices based on a phase detection result of the received phase detection signal
Implementation Method 3
a demodulation circuit for demodulating the modulated signal in the received distance measurement signal
Data Source
AI summary
A distance measurement system for transmitting and receiving a distance measurement signal including a phase detection signal between first and second devices and calculating a distance between the devices based on a phase detection result of the received phase detection signal includes a modulation circuit configured to generate the distance measurement signal including a modulated signal obtained by modulating an identification signal, a transmission circuit configured to transmit the distance measurement signal, a reception circuit configured to receive the distance measurement signal, a demodulation circuit configured to demodulate the modulated signal in the received distance measurement signal, and a control circuit configured to judge a restored state of the identification signal obtained from a demodulation result of the demodulation circuit.