Airborne Scanning Instrument Angled Mirror Shaft
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Solution Overview
Problem
Existing remote sensing instruments, particularly those in Low Earth Orbit (LEO) and Medium Earth Orbit (MEO), face challenges in achieving optimal radiometric quality and cost-effectiveness due to the rotation of detector arrays, which affects image collection and increases instrument complexity and cost, especially in the infrared range.
Innovation Solution
The proposed solution involves a scanning instrument with a tilted scanning mirror and shaft configuration, allowing for optimized tilt angles in the along-track direction, which limits linear array projection rotation and requires only a single scan mirror and motor, reducing size, weight, and cost while maintaining robust radiometric performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single detector is quickly scanned in the cross-track direction (point-scanner), then the scan rate increases, but the number of lines collected decreases
Solution Approach 1:
The patent divides the detection function into multiple segments by using a linear array of detectors instead of a single detector. This segmentation allows simultaneous collection of multiple lines while maintaining a manageable scan rate, resolving the contradiction between scan speed and productivity.
Solution Approach 2:
The patent transitions from one-dimensional point scanning to two-dimensional linear array detection. By adding the spatial dimension of multiple detectors arranged in a line, the system can collect multiple lines simultaneously, increasing productivity without sacrificing scan rate.
2Productivity
If a linear array of detectors are scanned (whisk-broom scanner), then the number of lines collected increases, but the scan rate decreases
Solution Approach 1:
The patent uses a linear array of detectors that spans the entire cross-track dimension, performing excessive detection action by collecting all necessary lines simultaneously rather than scanning them sequentially. This eliminates the need for repeated scanning, maintaining high productivity while achieving practical scan rates.
3Duration of action of moving object
If a linear array of detectors span the cross-track dimension simultaneously (push-broom), then the sample time increases, but scanning complexity increases
Solution Approach 1:
The patent extracts the scanning function from the detector array itself, using a separate scanning mirror to direct radiation to a single focal point on the detector array. This separation allows the detector array to remain simple while achieving push-broom functionality with extended sample time.
4Duration of action of moving object
If detector arrays are rotated to follow orbit path, then the sample time increases, but the instrument complexity and cost increase
Solution Approach 1:
The patent makes the scanning mirror the universal rotating component that performs multiple functions: it scans across the cross-track dimension and, when tilted at the appropriate angle, automatically aligns the scan path with the orbit trajectory. This single multi-functional component eliminates the need for separate rotation mechanisms for the detector array, reducing complexity while maintaining extended sample time.
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
This approach enables cost-effective, high-quality remote sensing by optimizing scanline path deviation and detector array alignment, reducing polarization effects, and supporting time-delayed integration, thus improving flexibility and reducing the need for complex mechanisms.
Implementation Method 1
a scanning mirror configured to be carried by an airborne platform, for example, a LEO satellite platform, and having a major reflective surface to define a scanning path directed toward Earth
Data Source
AI summary
An airborne scanning instrument may include a scanning mirror configured to be carried by an airborne platform and having a major reflective surface to define a scanning path directed toward Earth. The airborne scanning instrument may include a shaft configured to rotate the scanning mirror about a shaft axis. The major reflective surface of the scanning mirror may be tilted at a first angle from the shaft axis, and the shaft axis may be tilted at a second angle relative to horizontal. The airborne scanning instrument may include a detector aligned with the scanning mirror to define a detector path therewith.