Laser Rangefinder Spot-Size Ranging With Low Detectability
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Solution Overview
Problem
Current laser rangefinders are costly, complex, and their continuous laser pulses can be detected by enemies, revealing the user's position in military applications, posing a security risk.
Innovation Solution
A laser rangefinder device that uses a laser beam with a constant angle of divergence to project a spot of light on an object, which is then measured using a scale element to determine distance, displayed through an optical or digital imager, employing a reticle or pixels to align the spot with indicia for distance calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous laser pulses are emitted to enable accurate range determination, then measurement precision is improved, but the device becomes detectable by enemies and reveals user position
Solution Approach 1:
The patent applies periodic action by using pulsed laser beams instead of continuous emission. The laser emits short, periodic pulses at controlled intervals, allowing the system to accumulate multiple distance measurements over time while remaining undetectable between pulses. This periodic pulsing maintains measurement precision through averaging while eliminating continuous detectability that would reveal user position to enemies.
2Measurement precision
If very high-speed clocks and extremely accurate timing circuits are used to measure short time of flight, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies dynamics by making the laser pulse duration and repetition rate adjustable rather than fixed. The system dynamically adapts the pulse characteristics based on measurement requirements and environmental conditions. This allows optimization of the balance between measurement precision and device complexity, enabling the use of simpler timing circuits when high precision is not critical while maintaining the option for high precision when needed.
Solution Approach 2:
The patent applies parameter changes by varying multiple laser and timing parameters including pulse duration, repetition rate, and power levels. By changing these parameters, the system can achieve accurate range determination using less complex timing circuits in many practical scenarios, reducing the need for extremely high-speed clocks while maintaining sufficient measurement precision for the application.
3Measurement precision
If multiple pulses are employed to obtain averages and prevent errors, then measurement precision is improved, but the time required for measurement increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing lookup tables that correlate spot size measurements with distance values. Instead of requiring multiple time-consuming pulse measurements and averages, the system takes a single spot size measurement and quickly retrieves the corresponding distance from pre-computed tables. This eliminates the time loss associated with multiple pulses while maintaining measurement precision through the accuracy of the pre-calibrated relationship between spot size and distance.
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
Provides a simple, cost-effective, and secure method to determine distance by projecting a visible laser spot, aligning it with calibrated indicia, thus avoiding detection risks and reducing complexity.
Implementation Method 1
a laser beam, having a constant angle of divergence, projectable by the laser onto the object to create a spot of light on the object
Implementation Method 2
an optical device for collecting an image
Data Source
AI summary
A laser rangefinder device for determining the distance of an object includes an optical device for collecting an image, a laser associated with the optical device, and a laser beam having a constant angle of divergence. The laser beam is projectable onto the object to create a spot of light. The spot is included in the image. A scale element is carried by the optical device for determining a size of a dimension of the spot of light and using the size of the dimension to convert the spot of light to a distance to the object. A display device is carried by the optical device to display the collected image and the distance to the object.