Offset Speed Measurement Using Rangefinder Angular Displacement
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Solution Overview
Problem
Conventional speed measuring devices, such as radar and lidar, are limited by the 'cosine effect' when positioned offset from the object's path, resulting in inaccurate speed measurements due to the angle between the line-of-sight and the object's velocity vector, making it impractical to obtain accurate readings from non-aligned positions.
Innovation Solution
A speed measuring device equipped with rangefinder modules and processors that measure distances and angular displacements to calculate the absolute speed of an object based on the law of cosines, allowing for accurate speed determination from positions offset from the object's direction of movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the speed measuring device is positioned in line with the path of the moving object, then accurate speed measurements are obtained, but the device placement becomes less flexible and more difficult to operate in practical scenarios
Solution Approach 1:
The patent changes the measurement parameters from direct radial velocity measurement to multi-point distance measurement. By measuring distances at multiple positions and angles, and using trigonometric calculations, the system can determine absolute speed from offset positions without being constrained by the cosine effect, thus improving both measurement accuracy and operational flexibility
Solution Approach 2:
The patent introduces angular displacement as an intermediary parameter. Instead of directly measuring speed from an offset position, the system measures angular displacement between multiple line-of-sight directions and uses this intermediate measurement to calculate the object's absolute speed, effectively bridging the gap between offset positioning and accurate measurement
2Ease of operation
If the device is positioned perpendicular to the path of the moving object for convenience, then ease of operation is improved, but measurement precision deteriorates due to the cosine effect
Solution Approach 1:
The system transforms the measurement approach by changing from direct velocity measurement to distance-based angular measurement. By measuring distances at different angles and using trigonometric relationships, the device can operate from convenient perpendicular positions while maintaining measurement accuracy through mathematical compensation
Solution Approach 2:
The patent adds the angular dimension to the measurement process. Instead of measuring only along the line of motion, the system measures distances from offset positions at different angles, using the angular dimension to calculate absolute speed and eliminate the cosine effect limitation
3Device complexity
If conventional radar or lidar is used for speed measurement, then the measurement process is simplified, but the device cannot accurately measure speed from offset positions due to the cosine effect
Solution Approach 1:
The patent makes the rangefinder module universal by enabling it to perform both direct distance measurement and angular displacement measurement. This multi-functional approach allows the same device to operate in both aligned and offset configurations, eliminating the need for specialized equipment while maintaining measurement accuracy across different positioning scenarios
Solution Approach 2:
The patent replaces the direct velocity measurement mechanism with a geometric calculation system. Instead of using Doppler effect or other direct velocity sensing methods that are sensitive to angular offset, the system uses rangefinder distance measurements combined with angular displacement calculations to determine absolute speed, substituting mechanical/physical measurement with geometric computation
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 accurate speed measurements of objects from non-aligned positions, improving the practicality and accuracy of speed determination in various applications, including law enforcement and sports, by compensating for the cosine effect and providing precise radial velocity calculations.
Implementation Method 1
a rangefinder module configured to measure a distance from the device to the target object
Data Source
AI summary
Devices, methods, and computer program products for measuring the speed of an object. A speed measuring device includes a rangefinder module configured to measure distances from the device to a target object. Activating the device causes the device to measure a first distance from the device to the object along a first line-of-sight, and a second distance from the device to the object along a second line-of-sight. The device determines an angular displacement between the first line-of-sight and the second line-of-sight, and one or more of an elapsed time between measuring the first distance and measuring the second distance and a radial velocity of the object. The device then determines the absolute speed of the object based on the first distance, the second distance, the angular displacement, and one or more of the elapsed time and radial velocity.