Dual-mode imaging receiver electronic beam selection
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Solution Overview
Problem
Conventional optical communication receiver systems face challenges due to the need for precision mechanical pointing and alignment, which increases size, weight, and power consumption, as well as complexity, especially in systems with narrow fields of view and wide acquisition requirements, limiting their adoption in SWaP-constrained environments.
Innovation Solution
A dual-mode imaging receiver (DMIR) that employs electronic beam selection and a focal plane array with photodetectors and a read-out integrated circuit, allowing for simultaneous detection and tracking of multiple optical communication signals without precise mechanical pointing or spatial alignment, and can switch between photon-counting and photon-timing modes independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If precision mechanical gimbals are used for pointing and tracking, then detection precision is improved, but device complexity and size increase
Solution Approach 1:
The system divides the detection function across multiple fixed photodetector elements arranged in an array, each with its own narrow field of view. Instead of one detector that must physically point precisely, many detectors with fixed orientations collectively cover the required angular space, eliminating the need for precision mechanical gimbals while maintaining detection capability.
Solution Approach 2:
The patent replaces the mechanical pointing system (gimbals) with an electronic beam selection system. The focal plane array electronically selects which detector element receives signal from which direction, substituting mechanical rotation with electronic switching and signal processing to achieve the same functional outcome without moving parts.
2Object-affected harmful factors
If narrow field of view detectors are used, then background illumination suppression is improved, but acquisition search time increases
Solution Approach 1:
The system segments the field of view into multiple narrow detection channels, each with a photodetector element oriented to suppress background illumination from specific directions. By distributing the acquisition search across multiple parallel channels rather than one sequential channel, the system maintains narrow FOV benefits while reducing total search time through parallel processing.
Solution Approach 2:
The system performs preliminary scanning using the array of fixed detectors to identify potential signal sources before engaging the narrow FOV detection mode. The focal plane array pre-positions detection capability across multiple angles, so when a signal is detected, the system already has detectors oriented toward the source, eliminating the need for time-consuming mechanical repositioning.
3Object-affected harmful factors
If multiple detectors with narrow FOV are used, then background suppression is improved, but SWaP (size, weight, power) increases
Solution Approach 1:
The patent merges multiple photodetector elements and their associated narrow FOV channels into a single integrated focal plane array system. By combining the detection functions of multiple detectors into one unified array with shared electronics and processing, the system achieves the background suppression benefits of multiple narrow FOV detectors while reducing overall SWaP compared to having separate detector assemblies.
Solution Approach 2:
The focal plane array serves multiple functions simultaneously: it performs acquisition scanning across wide angles, maintains narrow FOV detection for background suppression, enables electronic beam steering, and provides parallel signal processing capabilities. This multi-functionality eliminates the need for separate acquisition and tracking subsystems, reducing overall system weight and complexity.
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 DMIR reduces the need for precision mechanical gimbals, enabling smaller, lighter, and less power-hungry systems that can support multiple concurrent free-space optical communication channels with reduced latency and increased efficiency, accommodating thousands of users with high data transfer rates without complex channel access protocols.
Implementation Method 1
A DMIR may include a focal plane array that comprises an array of photodetectors (e.g., an array of single-photon detectors, such as GmAPDs)
Data Source
AI summary
A dual-mode imaging receiver (DMIR) can acquire and maintain SOA free-space optical communication (FSOC) links without a precision mechanical gimbal. Unlike other FSOC technologies, a DMIR can operate without precise spatial alignment and calibration of the transmitter's or receiver's spatial encoders (precision pointing) in static (fixed point to point) geometries. Instead, a DMIR uses electronic receive beam selection to acquire and track transmitters with coarse mechanical pointing and a single aperture. And because the DMIR can operate with just one aperture, it does not need a beacon at the transmitter since it does not transition from a wide field-of-view acquisition aperture to a narrow field-of-view detection and decoding aperture even in dynamic geometries.