Uplink pre-compensation for ground-to-space optical communications using downlink tomographic reconstruction

Area of Science:

• Optical communications
• Atmospheric optics
• Wavefront sensing

Background:

• Uplink pre-compensation in ground-to-satellite optical links is challenging due to unavailable uplink path measurements.
• Accurate wavefront error measurement is crucial for effective pre-compensation.

Purpose of the Study:

• To develop and evaluate a method for estimating uplink wavefront error using accessible downlink measurements.
• To improve the performance of uplink pre-compensation in free-space optical communication systems.

Main Methods:

• Tomographic reconstruction of the common atmospheric volume using successive downlink beam measurements.
• Utilizing existing downlink wavefront sensors for data acquisition.
• Simulating performance under various atmospheric conditions.

Main Results:

• The proposed method successfully reconstructs uplink wavefront errors.
• Achieved significant reduction in residual mean-square wavefront error compared to direct downlink phase pre-compensation (up to 8.6 times less).
• Demonstrated good performance, particularly when the satellite point-ahead angle exceeds the isoplanatic angle.

Conclusions:

• The developed tomographic method provides a viable solution for uplink pre-compensation in optical satellite links.
• The method's hardware simplicity and effectiveness make it a promising approach for future optical communication systems.
• This technique enhances the reliability and performance of ground-to-satellite optical communication.