Dual-Sensor IR Missile Warning System with Confirmation Optics
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Solution Overview
Problem
Existing IR-optical missile warning systems face challenges in detecting missile signatures due to low detection certainty and high false alarms caused by strong background clutter and solar radiation, which is exacerbated by the need for a large field of view and short focal length.
Innovation Solution
The implementation of a dual-sensor system comprising an IR warning sensor and a confirmation sensor, where the confirmation sensor is designed with a larger focal length and higher F-number to reduce background radiation and enhance signal-to-background contrast, allowing for a narrow-band filter with steep edges to verify the spectral characteristics of detected targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a short focal length is used to achieve a large field of view, then the field of view is improved, but the background radiation increases and detection certainty decreases
Solution Approach 1:
The system divides the detection function into two separate sensors: a warning sensor with short focal length for broad field of view and a confirmation sensor with long focal length for high detection certainty. This segmentation allows each sensor to be optimized for its specific function without compromise.
Solution Approach 2:
The confirmation sensor acts as an intermediary verification system that receives targets detected by the warning sensor and provides spectral confirmation. This intermediary layer filters out false alarms by verifying the spectral signature before triggering alerts.
2Measurement precision
If a short focal length with small F number is used to detect point targets, then the sensitivity to point sources is improved, but the background clutter increases and false alarms increase
Solution Approach 1:
The detection function is segmented between two sensors with different optical characteristics. The warning sensor uses short focal length for sensitivity, while the confirmation sensor uses long focal length to reduce background clutter and verify spectral signatures.
Solution Approach 2:
The system changes the optical parameters (focal length and F number) between the two sensors to optimize their respective functions. The confirmation sensor has a long focal length and large F number to reduce background radiation and enhance spectral contrast.
3Reliability
If a narrow-band filter with steep edges is used to reduce background radiation, then the signal-to-background contrast is improved, but the filter optimization is limited by the large angular range of rays
Solution Approach 1:
The spectral filtering function is segmented between the two sensors. The warning sensor uses a broad-band filter for general detection, while the confirmation sensor uses a narrow-band filter with steep edges for spectral verification, taking advantage of the reduced angular range from the long focal length.
Solution Approach 2:
The filter characteristics are optimized according to the sensor's focal length and F number. The confirmation sensor's long focal length enables the use of narrow-band filters with steep edges that would be difficult to optimize for shorter focal lengths.
4Area of moving object
If a large entrance pupil is used to increase the field of view, then the field of view is improved, but the background radiation intensity increases
Solution Approach 1:
The system segments the detection function into two sensors with different pupil sizes and focal lengths. The warning sensor has a large pupil for broad field of view, while the confirmation sensor has a smaller effective pupil through its long focal length, reducing background radiation intensity.
Solution Approach 2:
The optical parameters including pupil size and focal length are changed between the two sensors to achieve different field of view and background radiation characteristics appropriate for their respective functions.
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 dual-sensor system significantly improves the reliability of missile detection by distinguishing missile signatures from false targets and reducing false alarms, enabling quick and accurate confirmation of missile presence through enhanced contrast values.
Implementation Method 1
Infrared warning sensors detect approaching missiles via the signature of the hot exhaust cloud: the characteristic is the IR emission of hot CO2 molecules in a narrow spectral band around 4.4 μm
Implementation Method 2
the characteristic is the IR emission of hot CO2 molecules
Implementation Method 3
the warning sensor is equipped with a bandpass filter that is designed for the spectral range of the IR signature around 4.4 μm
Implementation Method 4
the transmission range of the filter with a width of 50 nm is advantageous for the confirmation sensor
Implementation Method 5
the optics of the confirmation sensor include a bandpass filter whose transmission range is significantly narrower than that of the IR warning sensor
Data Source
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AI summary
The invention relates to an IR-optical system for missile warning, comprising an IR warning sensor for detecting missiles based on the IR signature of their exhaust plume in the mid-infrared, wherein a second IR sensor is provided which is sensitive to the same IR signature of the exhaust plume, for verifying the targets detected by the IR warning sensor. A method for detection using the optical system according to the invention is also the subject of the patent application.