Passive Hyperspectral Range Sensing for UAV Collision Avoidance
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Solution Overview
Problem
Existing radar and lidar systems for range calculation are costly, large, heavy, and require high power, making them unsuitable for smaller platforms like UAVs, while passive radar systems rely on target emissions and create detection risks, and existing lidar systems generate large datasets difficult to process.
Innovation Solution
A passive electro-optical sense and avoid system using hyperspectral imaging to estimate range by comparing an object's emission spectrum with a perfect blackbody, determining atmospheric path length and object size, and classifying the object type without emitting radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radar systems are used to calculate range to objects, then range measurement capability is improved, but the platform's position is revealed to adversaries and the system becomes costly, large, heavy and high power consuming
Solution Approach 1:
The patent inverts the traditional active radar approach by using passive detection. Instead of emitting radar signals and measuring reflections, the system receives and analyzes electromagnetic radiation naturally emitted by target objects. This allows range measurement without revealing the platform's position, as no active emissions are made that could be detected by adversaries.
Solution Approach 2:
The system changes the measurement parameters by utilizing naturally occurring electromagnetic radiation from objects rather than generated radar signals. By analyzing the spectral characteristics and intensity of emitted radiation across different frequencies, the system can estimate range without the harmful effects of active radar emissions.
2Measurement precision
If radar systems are used for range calculation, then range measurement capability is improved, but the system becomes expensive, large, heavy and high power consuming
Solution Approach 1:
The patent employs relatively inexpensive electro-optical sensors and spectral analysis equipment instead of costly radar systems. By using commercial off-the-shelf cameras and processors to analyze electromagnetic radiation, the system achieves range measurement capability at a fraction of the cost and weight of traditional radar systems, making it suitable for smaller platforms like UAVs.
3Measurement precision
If lidar systems are used for range calculation, then range measurement capability is improved, but the system becomes costly and generates very large datasets which are difficult to process
Solution Approach 1:
The patent extracts only the essential spectral features and intensity information from electromagnetic radiation rather than capturing complete high-resolution spatial data like lidar. By focusing on specific spectral bands and using atmospheric attenuation models, the system derives range information from simplified measurements, avoiding the generation of very large datasets that require complex processing.
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 undetectable range estimation with a lightweight, low-power system, providing accurate object discrimination and avoidance capabilities for smaller platforms.
Implementation Method 1
objects emitting radiation in the electromagnetic spectrum
Implementation Method 2
The received spectrum is compared with that of a perfect blackbody in order to identify relative troughs and/or discontinuities
Implementation Method 3
The spectral radiance (i.e. intensity at a given wavelength) or wavelength of these troughs and/or wavelengths of discontinuities in the emission spectrum is compared with known trough spectral radiances and/or wavelengths and discontinuity wavelengths at different atmospheric path lengths
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
The present invention provides a method suitable for use in a sense and avoid system of a vehicle having a hyperspectral imaging system, the method comprising: estimating the range to an object from the vehicle, wherein estimating the range comprises: measuring the emission spectrum of the object using the hyperspectral imaging system; identifying at least one trough and/or discontinuity in the emission spectrum by subtracting the measured emission spectrum from a perfect blackbody emission spectrum; and searching a storage means storing spectral radiances and/or wavelengths of troughs and/or discontinuities, each with an associated known atmospheric path length, for the corresponding spectral radiance and/or wavelength of the identified at least one trough and/or discontinuity in order to estimate the atmospheric path length, and consequently the range, between the object and the vehicle. The present invention also provides a sense and avoid system for performing the same method.