Pointing, acquisition, and tracking system for a mobile-platform optical communication system
An optical communication receiver system for a mobile platform includes: a surface having an entrance aperture for entry of an optical communication signal from a remote source; an optical receiver to receive the optical communication signal through the entrance aperture; a reflective layer over at least a portion of the surface to at least partially reflect an alignment beam that is substantially coincident with the optical communication signal; a camera positioned to detect the reflected alignment beam; a processor to determine alignment information about the alignment beam relative to the entrance aperture based on the reflected alignment beam detected by the camera; and a transmitter to transmit the alignment information to the remote source to enable the remote source to center the optical communication signal in the entrance aperture.
1 . An optical communication receiver system for a mobile platform, comprising:
a surface having an entrance aperture for entry of an optical communication signal from a remote source;
an optical receiver to receive the optical communication signal through the entrance aperture;
a reflective layer over at least a portion of the surface to at least partially reflect an alignment beam that is substantially coincident with the optical communication signal;
a camera positioned to detect the reflected alignment beam;
a processor to determine alignment information about the alignment beam relative to the entrance aperture based on the reflected alignment beam detected by the camera; and
a transmitter to transmit the alignment information to the remote source to enable the remote source to center the optical communication signal in the entrance aperture.
2 . The optical communication receiver system of claim 1 , further comprising:
a pivotable support mechanism to adjust an orientation of the surface such that the entrance aperture is substantially perpendicular to a wavefront of the optical communication signal.
3 . The optical communication receiver system of claim 2 , further comprising a beacon detector to detect a beacon signal from the remote source, wherein the pivotable support mechanism adjusts the orientation of the surface based on a direction of the remote source determine from the beacon signal.
4 . The optical communication receiver system of claim 3 , wherein the beacon detector is an optical detector positioned to receive a portion of the alignment beam transmitted through the reflective layer and the entrance aperture.
5 . The optical communication receiver system of claim 2 , wherein the pivotable support mechanism comprises a gimbal to rotate the surface relative to the mobile platform.
6 . The optical communication receiver system of claim 1 , wherein the reflective layer is at least partially reflective at a first wavelength of the alignment beam and transmissive at a second wavelength of the optical communication signal, the second wavelength being different from the first wavelength.
7 . The optical communication receiver system of claim 6 , wherein the optical receiver is a quantum free-space optical receiver to receive a quantum free-space optical communication signal.
8 . The optical communication receiver system of claim 6 , wherein the alignment beam is a classical free-space communication signal and the reflective layer is partially transmissive at the second wavelength, the optical communication receiver system further comprising a second optical receiver to receive a portion of the alignment beam transmitted through the reflective layer and the entrance aperture.
9 . The optical communication receiver system of claim 1 , wherein the reflective layer is a diffuse reflective layer.
10 . The optical communication receiver system of claim 1 , wherein the optical communication receiver system does not include a fast steering mirror.
11 . The optical communication receiver system of claim 1 , wherein the optical communication receiver system includes no moving components in an optical path of the optical communication signal.
12 . The optical communication receiver system of claim 1 , wherein the optical communication receiver system supports a receive-only optical communication channel with the remote source.
13 . The optical communication receiver system of claim 1 , further comprising a boom on which the camera is mounted.
14 . A pointing, acquisition, and tracking system, comprising:
a reflective layer in an optical path between a remote source and a surface having an entrance aperture through which an optical communication signal from the remote source is receivable by an optical receiver, the reflective layer being at least partially reflective to an alignment beam from the remote source that is substantially coincident with the optical communication signal;
a camera positioned to detect the alignment beam reflected by the reflective layer;
a processor to determine alignment information about the alignment beam relative to the entrance aperture based on the alignment beam detected by the camera;
a transmitter to transmit the alignment information to the remote source to enable the remote source to center the optical communication signal in the entrance aperture;
a beacon detector to detect a beacon signal from the remote source; and
a pivotable support mechanism to adjust an orientation of the surface to be substantially perpendicular to a wavefront of the optical communication signal based on a direction of the remote source determined from the beacon signal.
15 . The pointing, acquisition, and tracking system of claim 14 , wherein the beacon detector is an optical detector positioned to receive a portion of the alignment beam transmitted through the reflective layer and entrance aperture.
16 . The pointing, acquisition, and tracking system of claim 14 , wherein the reflective layer is partially transmissive to the alignment beam, the pointing, acquisition, and tracking system further comprises a second optical receiver to receive a portion of the alignment beam transmitted through the reflective layer.
17 . The pointing, acquisition, and tracking system of claim 16 , wherein the second optical receiver is the beacon detector.
18 . The pointing, acquisition, and tracking system of claim 14 , wherein the pointing, acquisition, and tracking system does not include a fast steering mirror or any moving components in an optical path of the optical communication signal.
19 . A method of aligning an optical communication signal from a remote source with an optical receiver on a mobile platform to receive the optical communication signal through an entrance aperture in a surface, the method comprising:
detecting with a camera an alignment beam from the remote source, substantially coincident with the optical communication signal, and reflected by a reflective layer in front of the surface;
determining, from the reflected alignment beam, alignment information about the alignment beam relative to the entrance aperture; and
transmitting the alignment information to the remote source to enable the remote source to center the optical communication signal in the entrance aperture.
20 . The method of claim 19 , further comprising:
detecting with a beacon detector a beacon signal from the remote source; and
adjusting, via a pivotable support mechanism, an orientation of the surface to be substantially perpendicular to a wavefront of the optical communication signal based on a direction of the remote source determined from the beacon signal.