Quadrant Array Detector Field of View Limit Detection
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Solution Overview
Problem
Existing quadrant-array detector systems struggle to accurately detect when a target is approaching or exceeding the field of view limit, relying on reducing signal strength which is inefficient and costly, or using expensive continuous detection systems, and cannot differentiate between targets near the field-of-view edge and those with decreasing irradiance.
Innovation Solution
A two-dimensional array of photodiodes with an additional photodiode placed around the perimeter, allowing for discrimination between targets moving off the edge and those with decreasing irradiance without physical barriers or active area termination, providing clear field-of-view limit information for guidance processors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed physical barrier is placed at the field of view limit to detect target position, then field of view limit detection is achieved, but the amount of signal reaching the quadrant detector is reduced
Solution Approach 1:
The detector is segmented into a two-by-two array of photodiodes, with each photodiode responsible for a specific quadrant. This segmentation allows the system to detect target position by comparing signals from different quadrants without requiring physical barriers, thereby maintaining full signal strength while achieving precise field of view limit detection.
Solution Approach 2:
The patent introduces an intermediary computational approach using signal processing and mathematical calculations to determine target position. Instead of using physical barriers to block or redirect signals, the system uses the relative signal strengths from different photodiodes as intermediaries to calculate whether the target is within the field of view limit.
2Reliability
If the active area of the quadrant detector is terminated at the field of view limit to reduce signal, then field of view compliance is achieved, but the detector cannot differentiate between targets near the edge and those with decreasing irradiance
Solution Approach 1:
Each photodiode in the two-by-two array has a specific local function corresponding to a quadrant of the field of view. By analyzing the signal distribution across these locally-defined quadrants, the system can determine both field of view compliance and target position information, including whether the target is near the edge or has decreasing irradiance.
Solution Approach 2:
The system uses feedback from the relative signal strengths of the four photodiodes to continuously determine target position and field of view status. The guidance processor receives this feedback and can distinguish between targets near the field of view edge and those with decreasing irradiance by analyzing the pattern of signals from different quadrants.
3Measurement precision
If expensive continuous detection systems are used to track target position accurately, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The two-by-two array of photodiodes serves multiple functions: it detects target position, determines field of view limit compliance, and provides information about target motion direction. This multi-functionality eliminates the need for separate continuous detection systems, reducing device complexity and cost while maintaining measurement precision.
Solution Approach 2:
The quadrant detector system is self-sufficient in providing all necessary target position and field of view information through its own signal processing capabilities. The guidance processor uses the signals from the four photodiodes to independently determine target status without requiring additional external detection systems.
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 accurate and cost-effective detection of target entry or exit from the field of view, enhancing target tracking and guidance algorithms, and is applicable to various optical guidance systems.
Implementation Method 1
a two-dimensional array of photodiodes
Data Source
AI summary
A method of making a device comprising one or more quadrant detectors (and such a detector) comprising fabricating a two-dimensional array of photodiodes and placing one or more photodiodes around the perimeter of the array.