Satellite Optical Link Using RF Positioning
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Solution Overview
Problem
Current optical transmission methods from satellites to reception terminals face challenges due to the low angular divergence of laser beams, requiring complex and costly terminals with precise pointing systems, which are particularly disadvantageous for satellite applications where data transmission time is limited by visibility duration.
Innovation Solution
A method utilizing radio frequency signals to transmit satellite position coordinates to the reception terminal, allowing for quick initial alignment without the need for precise pointing, and then adjusting the optical receiver's direction in real-time to maximize laser beam reception power, potentially eliminating the need for an optical transmitter acquisition and tracking system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical terminal performs an angular scan to detect the laser beam, then the acquisition precision is improved, but the acquisition time increases and the device complexity increases
Solution Approach 1:
The patent applies preliminary action by using radio frequency signals to transmit satellite position coordinates before optical communication begins. The ground station receives these coordinates in advance and pre-positions the optical receiver, eliminating the need for time-consuming angular scanning during the actual acquisition phase.
Solution Approach 2:
The patent introduces radio frequency signals as an intermediary carrier to transmit position information. This intermediary mechanism allows the receiving terminal to acquire position data without requiring complex optical scanning systems, thereby reducing both acquisition time and device complexity.
2Speed
If a fast high-range system is equipped for varying transmission/reception direction, then the acquisition speed is improved, but the device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical angular scanning system with a radio frequency-based position coordinate transmission system. Instead of mechanically varying the transmission/reception direction to acquire signals, the system uses radio frequency signals to provide position information that enables direct optical communication setup.
3Reliability
If the acquisition phase is extended to ensure precise detection, then the detection reliability is improved, but the data transmission time decreases
Solution Approach 1:
By performing preliminary position coordinate reception via radio frequency signals, the system ensures reliable detection without extending the actual data transmission phase. The ground station pre-acquires satellite position information, allowing immediate transition to data transmission once the satellite enters the visibility window.
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 reduces the complexity and cost of the reception terminal, extends data transmission time by eliminating the need for complex pointing systems, and allows for efficient optical data transfer with minimal additional hardware, such as no optical signal transmission path or acquisition system in the terminal.
Implementation Method 1
Optical transmission occurs when an optical transmitter emits a modulated laser beam and sends it to an optical receiver
Implementation Method 2
the satellite's position coordinates can be received by the optical receiving terminal via radio frequency
Data Source
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AI summary
A method of optical transmission of useful data comprises a prior transmission by radiofrequency, from a satellite (10) to an optical reception terminal (20), of position coordinates of the satellite. The terminal then orients a direction of optical reception towards the satellite to receive the useful data. According to an enhancement, a direction of optical emission of the satellite can sweep an angular sector so as to maximize an optical reception power at the level of the terminal. The optical transmission equipment is then reduced to an optical emission pathway for the satellite, which pathway is devoid of any coarse pointing system and optionally also of any fine pointing system, and to an optical reception pathway for the reception terminal. The satellite and the terminal can also be devoid of any system for acquisition and tracking of optical emitter.