Self-Mixing Interference Velocity Sensor Reliability Assessment
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Solution Overview
Problem
Existing velocity measurement systems, such as self-mixing interference (SMI) sensors, lack reliability, making it unsafe to use their velocity data in Electronic Stability Programs (ESP) or other vehicle safety systems, as the measured velocity may not be reliable enough to trigger safety actions.
Innovation Solution
A velocity determination apparatus that includes a laser with a cavity for emitting and reflecting radiation, an interference signal detector, and a velocity determination unit, along with a reliability value determination unit to assess the reliability of the measured velocity, ensuring it meets safety standards before use in safety systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a self-mixing interference sensor is used for velocity measurement, then real-time velocity measurement is achieved, but the reliability of the measured velocity is insufficient for safety systems
Solution Approach 1:
The patent implements feedback by continuously monitoring the signal-to-noise ratio of the interference signal and using this information to dynamically adjust the reliability assessment. The reliability value determination unit uses the detected signal quality as feedback to determine whether the velocity measurement is reliable enough for safety system activation, creating a closed-loop quality control mechanism.
Solution Approach 2:
The patent introduces an intermediary reliability value determination unit that acts as a mediator between the velocity measurement and the safety system. This intermediary assesses the quality of the measurement through signal-to-noise ratio analysis and provides a reliability indicator, preventing direct use of potentially unreliable velocity data while maintaining the benefits of the SMI sensor.
2Reliability
If the reliability value determination unit is added to assess velocity reliability, then the safety system can use the velocity data reliably, but the device complexity increases
Solution Approach 1:
The patent merges the reliability determination functionality into the existing velocity determination apparatus by integrating the reliability value determination unit with the interference signal detector and velocity determination unit. This combination approach allows the system to perform both velocity measurement and reliability assessment within a unified device architecture, reducing overall system complexity compared to separate independent systems.
Solution Approach 2:
The reliability value determination unit serves multiple functions: it monitors signal-to-noise ratio, assesses measurement reliability, and provides quality indicators for safety system decision-making. This multi-functional design allows a single component to address multiple requirements, thereby minimizing the increase in device complexity while achieving comprehensive reliability assessment.
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 apparatus provides a reliable velocity measurement that can be safely used in vehicle safety systems by determining the reliability of the velocity data, preventing unsafe actions based on unreliable data.
Implementation Method 1
the first radiation and at least a part of the second radiation interfere within the laser cavity
Implementation Method 2
The intensity of the laser light in the cavity is modified by the interference of the first radiation with the second radiation, which is preferentially backscattered light and which is frequency shifted by a Doppler shift resulting from the relative movement of the two objects
Data Source
AI summary
The invention relates to a velocity determination apparatus for determining a relative velocity between a first object (12), to which the velocity determination apparatus is attachable, and a second object (1). The velocity determination apparatus comprises a laser (3) having a laser cavity (4) for emitting first radiation (5), which is reflected by the second object (1), wherein the reflected radiation interferes with the first radiation (5) within the laser cavity (4). An interference signal detector (7) detects an interference signal depending on the interference within the laser cavity (4) and a velocity determination unit (8) determines the relative velocity based on the interference signal. A reliability value determination unit (9) determines a reliability value for indicating the reliability of the determined relative velocity based on at least one of the group consisting of the detected interference signal, the determined relative velocity and a characteristic of the laser.