Catadioptric Boresighting Apparatus for Multi-Sensor Alignment
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Solution Overview
Problem
Conventional boresighting modules are complex, bulky, and not suitable for compact applications, and they fail to simultaneously align multiple imaging sensors with different wavelength responsivity, leading to alignment drifts over time and temperature.
Innovation Solution
A compact boresighting apparatus using a catadioptric element with a positive meniscus lens and a target object made of fluorescent material that absorbs laser light and emits light in detectable infrared wavebands, allowing simultaneous alignment of multiple imaging sensors with different types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional boresighting modules are used, then alignment accuracy can be maintained, but the device becomes complex and bulky
Solution Approach 1:
The patent combines the focusing and collimating functions into a single catadioptric element, merging multiple optical components into one integrated structure. This reduces the number of separate parts while maintaining the alignment functionality, directly addressing the complexity issue while preserving measurement precision.
Solution Approach 2:
The catadioptric element serves multiple functions: it acts as both a focusing element for the laser beam and a collimating mirror for the reflected light. Additionally, the target object serves as both the alignment reference and the wavelength conversion medium. This multi-functionality reduces overall system complexity while maintaining alignment accuracy.
2Measurement precision
If conventional boresighting modules are used, then alignment can be performed, but the module is too bulky for compact applications
Solution Approach 1:
By merging the focusing lens and collimating mirror into a single catadioptric element, the physical space required is reduced. The integrated design eliminates the need for separate mounting structures and spacing between components, directly reducing the module volume while maintaining alignment capability.
Solution Approach 2:
The patent places the target object at the focal plane within the compact optical arrangement, effectively nesting the target within the optical path rather than requiring external positioning. This nesting approach minimizes the overall footprint of the boresighting module.
3Measurement precision
If conventional boresighting modules are used, then single sensor alignment can be achieved, but multiple imaging sensors cannot be aligned simultaneously
Solution Approach 1:
The target object is designed to convert a single laser wavelength into multiple emitted wavelengths that correspond to the sensitivity ranges of different imaging sensors. This universal wavelength conversion capability allows the same boresighting apparatus to align multiple sensor types (e.g., SWIR, MWIR, LWIR) simultaneously, enhancing adaptability while maintaining alignment precision.
Solution Approach 2:
The target object changes the wavelength parameter of the light through fluorescence conversion. By absorbing laser light at one wavelength and emitting at multiple different wavelengths, the target enables a single alignment source to serve multiple sensors with different spectral responses, resolving the contradiction between single-sensor optimization and multi-sensor versatility.
4Measurement precision
If thermal targets are used in boresighting, then alignment can be performed, but the target burns away and must be replaced regularly
Solution Approach 1:
The patent reverses the disposable approach by using a fluorescent target material that is inherently stable and non-consumable. Unlike thermal targets that burn away, the fluorescent material can be repeatedly excited by the laser without degrading, eliminating the need for regular replacement while maintaining alignment reference precision.
Solution Approach 2:
The patent changes the operational parameter of the target from thermal emission (which consumes the target material) to fluorescent emission (which does not). This parameter change from thermal to optical excitation fundamentally extends the target's operational lifespan while maintaining its function as an alignment reference.
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 solution provides a compact, efficient method for maintaining accurate alignment of laser beams with imaging sensors, enabling simultaneous boresighting of multiple sensors and reducing the need for frequent target replacement.
Implementation Method 1
a catadioptric element configured to transmit and focus the laser beam onto a location in a focal plane
Implementation Method 2
a target object positioned substantially at the focal plane and configured to emit, from a spot corresponding to the location of the focused laser beam, light having a second wavelength within the detectable waveband of the imaging sensor in response to receiving the laser beam
Implementation Method 3
the catadioptric element is further configured as a collimating mirror to reflect the emitted light from the spot on the target object into a collimated emitted light having the second wavelength to be detected by the imaging sensor
Data Source
AI summary
Techniques are disclosed for an improved boresighting apparatus and related method for boresighting a light source to an imaging sensor, and for an improved material to be used in a target object in such a boresighting apparatus. For example, an apparatus for use in boresighting may include a catadioptric element and a target object, where the catadioptric element is configured to focus a laser beam from the light source and also to collimate light emitted from the target object at a different wavelength than the laser beam to be detected by the imaging sensor for indicating the location of the focused laser beam. The target object may, for example, comprises a fluorescent optical material doped with one or more optically active ions to absorb light having the wavelength of the laser beam and emit light in one or more wavebands detectable by the imaging sensors.