Feedforward motion compensation for FSOC terminals
The technology relates to free-space optical communication systems that correct for errors in tracking and pointing accuracy to maintain connection integrity. Such systems can both proactively and reactively correct for errors in tracking performance and pointing accuracy of terminals within the system. An aspect includes receiving information indicative of at least one external disturbance associated with a communication device. A determination is made for a proactive estimation indicative of a first error associated with an effect of the at least one external disturbance at a current timestep. A determination is made for a reactive estimation indicative of a second error associated with the effect of the at least one external disturbance at a previous timestep. A final control signal is determined based on the proactive estimation and the reactive estimation. A controller is able to actuate an optical assembly of the communication device based on the determined final control signal.
1 . A method for adjusting an optical link alignment of a first communication device with a remote communication device, the method comprising:
determining, by one or more processors of the first communication device, a proactive estimation based on at least one external disturbance at a first timestep, wherein determining the proactive estimation includes use of a feedforward gain scheduling approach;
determining, by the one or more processors of the first communication device, a reactive estimation based on the at least one external disturbance at a second timestep; and
actuating, by a controller, an optical assembly of the first communication device based on the proactive estimation and the reactive estimation, the actuating including determining, by the one or more processors, a final control signal based on the proactive estimation and the reactive estimation.
2 . The method of claim 1 , wherein the first timestep is a current timestep and the second timestep is a previous timestep.
3 . The method of claim 1 , wherein the feedforward gain scheduling approach is defined by:
u _FF( t )= G _FF( m ),
where u_FF(t) is the proactive estimation, t is time, G_FF is a feedforward function, and m is information indicative of the at least one external disturbance from the first timestep.
4 . The method of claim 1 , wherein determining the reactive estimation based on the at least one external disturbance at the second timestep includes use of a feedback gain scheduling approach.
5 . The method of claim 4 , wherein the feedback gain scheduling approach is defined by:
u _FB( t )= G _FB( m ),
where u_FB(t) is the reactive estimation, t is time, G_FB is a feedback function, and m is information indicative of the at least one external disturbance from the second timestep.
6 . The method of claim 1 , wherein:
the proactive estimation is a first error; and
the reactive estimation is a second error.
7 . The method of claim 6 , wherein the final control signal is determined by summing the first error and the second error.
8 . The method of claim 1 , wherein actuating the optical assembly of the first communication device based on the proactive estimation and the reactive estimation includes adjusting a target location or a setpoint location.
9 . The method of claim 1 , further comprising instructing the remote communication device to adjust a target location or a setpoint location based on the proactive estimation and the reactive estimation.
10 . The method of claim 1 , wherein the reactive estimation is based on behavior information of the remote communication device from the second timestep.
11 . The method of claim 10 , wherein the behavior information includes one or more factors associated with the remote communication device.
12 . The method of claim 11 , wherein the one or more factors include at least one of a setpoint of the remote communication device, a pose of the remote communication device, an angular velocity of the remote communication device, acceleration of the remote communication device, or a target location of the remote communication device.
13 . A communication device comprising one or more processors configured to:
determine a proactive estimation based on at least one external disturbance at a first timestep, wherein determining the proactive estimation includes use of a feedforward gain scheduling approach;
determine a reactive estimation based on the at least one external disturbance at a second timestep; and
cause an optical assembly of the communication device to actuate based on the proactive estimation and the reactive estimation, the actuation including a determination of a final control signal based on the proactive estimation and the reactive estimation.
14 . The communication device of claim 13 , wherein the first timestep is a current timestep and the second timestep is a previous timestep.
15 . The communication device of claim 13 , wherein the feedforward gain scheduling approach is defined by:
u _FF( t )= G _FF( m ),
where u_FF(t) is the proactive estimation, t is time, G_FF is a feedforward function, and m is information indicative of the at least one external disturbance from the first timestep.
16 . The communication device of claim 13 , wherein the determination of the reactive estimation based on the at least one external disturbance at the second timestep includes use of a feedback gain scheduling approach.
17 . The communication device of claim 16 , wherein the feedback gain scheduling approach is defined by:
u _FB( t )= G _FB( m ),
where u_FB(t) is the reactive estimation, t is time, G_FB is a feedback function, and m is information indicative of the at least one external disturbance from the second timestep.
18 . The communication device of claim 13 , wherein the communication device is stationary.
19 . The communication device of claim 13 , wherein the communication device is mobile.