Laser Communication System Celestial Navigation Fix
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Solution Overview
Problem
Current laser communication systems require several minutes to establish an initial link between high-altitude vehicles or satellites due to the need for a sequential step-stare search process within a field of uncertainty, which can be inefficient and time-consuming.
Innovation Solution
The use of an integrated Acquisition and Tracking Sensor (ATS) within the laser communication system to perform a celestial navigation fix, allowing for rapid acquisition and establishment of a laser link without the need for a separate star tracker or GPS, by pointing a narrow laser beam co-boresighted with the ATS at a star to determine the attitude and location of a second platform within the field of uncertainty.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sequential step-stare search process is used to establish a laser communication link, then the system can reliably acquire the second platform within the field of uncertainty, but the acquisition time becomes excessively long (several minutes)
Solution Approach 1:
The system performs preliminary star tracker observations to determine the first platform's attitude and position before initiating the laser link acquisition. This preliminary celestial navigation fix reduces the field of uncertainty, allowing the subsequent laser acquisition to start from a more precise initial position rather than searching the entire uncertainty region sequentially.
Solution Approach 2:
The ATS (Acquisition and Tracking Sensor) is designed to perform multiple functions: it can detect stars for celestial navigation fixes and detect laser beams for communication link acquisition. By making the sensor multi-functional, the system eliminates the need for separate star tracker equipment and uses the same sensor for both attitude determination and laser acquisition, thereby reducing overall system complexity and acquisition time.
2Measurement precision
If a separate star tracker is added to perform celestial navigation fix, then the attitude determination precision is improved, but the device complexity and cost increase
Solution Approach 1:
The ATS is designed to perform multiple functions: it can detect stars for celestial navigation fixes and detect laser beams for communication link acquisition. By making the sensor multi-functional, the system eliminates the need for separate star tracker equipment and uses the same sensor for both attitude determination and laser acquisition, thereby reducing overall system complexity and acquisition time.
Solution Approach 2:
The system merges the star detection capability and laser detection capability into a single ATS sensor. The sensor can operate in different modes (star tracking mode and laser acquisition mode) using the same hardware platform, optical path, and signal processing chain, thereby combining multiple functions into one integrated system.
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 significantly reduces the acquisition time from minutes to less than ten seconds, enabling quicker and more efficient establishment of laser communication links between high-altitude platforms, even in degraded or denied GPS environments.
Implementation Method 1
determining attitude of the first platform based, at least in part, on the ATS and gimbal measurement of the angular orientation of one or more stars
Implementation Method 2
transmit and receive large amounts of data, typically at very high data rates
Data Source
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AI summary
A laser communication system its integrated microradian-accuracy Acquisition and Tracking Sensor (ATS) to perform a celestial navigation fix to determine the attitude of the laser communications payload, including the integrated ATS and the co-boresighted laser beam, prior to establishing a laser communication link with a second vehicle such as a high-altitude aircraft or satellite. The laser communication system may use a legacy platform INS to initially point its narrow FOV ATS at one or more stars to obtain the vehicle's attitude therefrom. Then the precision payload attitude determined with the ATS star tracker fix is used to point the co-boresighted laser beam to establish a laser communications link with the second vehicle.