An implementation of the method to estimate the direction of the laser beam emitted from ground to satellite is proposed. The implementation employs two boresight cameras to observe the backscattered light of the emitted beam. To carry out the proposed method, it is necessary to estimate the center line of the image of the scattered light from the laser beam taken by the boresight camera. A simple method to find the center line of the image of the backscattered light is also proposed. Since the accuracy of the estimation of the beam propagation direction should be known to design a free-space optical terminal, an experiment is performed to measure the angular error of the estimation by the proposed method.

Chapter Contents:

• 18.1 Introduction
• 18.2 Estimating beam propagation direction using dual boresight camera
• 18.3 Experimental method to measure the angular error
• 18.3.1 Experimental method
• 18.3.2 Geometrical angular error
• 18.3.3 The procedure of the experiment
• 18.3.3.1 The setup for this experiment
• 18.3.3.2 The method to obtain the center line of image of scattered light
• 18.3.3.3 Observation for the experiment
• 18.3.4 Results
• 18.4 Conclusion
• References

Inspec keywords: light propagation; optical links; laser beams; backscatter

Other keywords: boresight camera; emitted beam; backscattered light; scattered light; beam propagation direction; center line; laser beam

Subjects: Light propagation; Free-space optical links