Measuring Apparatus for Moving Targets Using Inclined Optical Axes
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Solution Overview
Problem
Existing distance measuring apparatus using frequency-shifted feedback laser (FSF laser) struggles to accurately measure distances and velocities of targets that are moving, particularly in the in-plane direction, and fails to account for the inclination angle of the optical axis, leading to measurement inaccuracies due to Doppler shifts.
Innovation Solution
A measuring apparatus and method that employs multiple measuring heads with inclined optical axes to split and detect laser light, calculating the beat frequency and inclination angle to accurately measure separation displacement and moving velocity, accounting for Doppler shifts and optical axis inclination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If laser light is directed perpendicular to the target surface for distance measurement, then the measurement setup is simple, but the apparatus cannot measure velocity components in the in-plane direction
Solution Approach 1:
The invention divides the velocity measurement task into multiple components by using multiple measuring heads with different optical axis orientations. Each measuring head measures a specific projection of the velocity vector, and the arithmetic processing unit combines these measurements to calculate the complete velocity vector, enabling both simple perpendicular measurement and in-plane velocity measurement.
Solution Approach 2:
The invention transitions from one-dimensional measurement (perpendicular to target surface) to multi-dimensional measurement by introducing measuring heads with optical axes oriented at different angles. This allows the system to capture velocity components in multiple directions, including in-plane motion, while maintaining the simplicity of perpendicular measurement capability.
2Device complexity
If the optical axis is perpendicular to the target surface, then the measurement configuration is straightforward, but Doppler shifts from in-plane motion cannot be detected
Solution Approach 1:
The velocity detection capability is segmented across multiple measuring heads, each oriented at different angles. This segmentation allows the system to detect Doppler shifts from in-plane motion by combining measurements from multiple orientations, improving velocity measurement accuracy without significantly increasing the complexity of individual optical configurations.
Solution Approach 2:
The system uses a composite measurement approach by combining data from multiple measuring heads with different optical axis orientations. This composite measurement strategy enables accurate detection of velocity vectors in three-dimensional space, including in-plane components, while keeping each individual measuring head relatively simple.
3Device complexity
If a single measuring head with fixed optical axis is used, then the device structure is simple, but it cannot accurately measure targets moving in arbitrary directions
Solution Approach 1:
The measurement function is segmented across multiple measuring heads, each with a fixed optical axis oriented at a specific angle. This segmentation allows the system to measure targets moving in arbitrary directions by combining measurements from multiple fixed orientations, achieving versatility without requiring each individual measuring head to be complex or adjustable.
Solution Approach 2:
The system achieves multi-functionality by using multiple measuring heads with different optical axis orientations. Each measuring head performs a specific measurement function based on its orientation, and together they provide universal measurement capability for targets moving in any direction within the measurement space.
4Device complexity
If the beat frequency is calculated without considering optical axis inclination, then the calculation is simple, but measurement accuracy deteriorates for moving targets
Solution Approach 1:
The system performs preliminary action by pre-storing the inclination angles of the optical axes of the measuring heads. This allows the arithmetic processing unit to accurately calculate beat frequencies and derive velocity vectors by incorporating these predetermined angle values, improving measurement precision without significantly increasing calculation complexity.
Solution Approach 2:
The system uses feedback by incorporating the known optical axis inclination angles into the beat frequency calculation process. The arithmetic processing unit uses this feedback information to correct and refine the velocity measurements, ensuring high accuracy for targets moving in arbitrary directions while maintaining relatively simple calculations.
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
Enables precise measurement of moving targets' velocities and displacements, even when moving in the in-plane direction, by compensating for Doppler shifts and optical axis inclination, thereby improving measurement accuracy.
Implementation Method 1
laser light that is modulated with respect to time by a predetermined frequency modulation velocity
Implementation Method 2
a beat signal having the same frequency as a frequency difference between the reflection light and the reference light is detected by interference between the reflection light and the reference light
Implementation Method 3
The light detection unit converts an optical signal into an electric signal
Implementation Method 4
measuring apparatus and a measuring method in which a relative moving velocity of a target to be measured or a displacement between the measuring apparatus and the target to be measured (a distance to the target to be measured from the measuring apparatus) can be accurately measured even in a case where the target to be measured is moved
Data Source
AI summary
The present invention provides a measuring apparatus and a measuring method in which a relative moving velocity of a target to be measured or a separation displacement of the target to be measured can be accurately measured even in a case where the target to be measured is moved. In a measuring apparatus, a relative moving velocity of a target to be measured and a separation displacement of the target to be measured can be measured in consideration of the influence of Doppler shift that occurs due to the movement of the target to be measured in an in-plane direction, and thus, even in a case where the target to be measured is moved in the in-plane direction, the relative moving velocity of the target to be measured and the separation displacement of the target to be measured can be accurately measured.