Methods and apparatus to point a payload at a target

摘要

Methods and Apparatus to point a payload at a target are disclosed herein. An example method includes estimating a first orientation of a base of a payload to point the payload at a target. The base is coupled to a satellite via a pivot joint and a linear actuator. The linear actuator is to enable adjustment of an azimuth angle and an elevation angle of the base. The example method further includes communicating a command to actuate the actuator to move the base to the first orientation and determining a base orientation error. The base orientation error is a difference between the first orientation and a second orientation of the base to which the actuator moves the base in response to the command. The example method also includes determining a stroke position error of the actuator based on the base orientation error.

主权项

1. A method of operating a satellite, the method comprising:
operating the satellite having a payload attached to a substantially planar base, the base having a first contact point directly coupled to a pivot joint, a second contact point directly coupled to a first linear actuator and a third contact point directly coupled to a second linear actuator, the first and second linear actuators to move the base via the pivot joint about an azimuth angle and an elevation angle to position the base relative to a target, the base having only the first and second linear actuators to move the base about the pivot joint relative to the azimuth angle and the elevation angle; estimating a target pointing direction of the base to point the payload at the target; determining a first estimated stroke position of the first linear actuator and a second estimated stroke position of the second linear actuator to position the base at the target pointing direction; obtaining a base orientation error; determining a first stroke position error of the first linear actuator and a second stroke position error of the second linear actuator based on the base orientation error; determining a first corrected stroke position of the first linear actuator based on a difference between the first stroke position error and the first estimated stroke position; determining a second corrected stroke position of the second linear actuator based on a difference between the second stroke position error and the second estimated stroke position; and commanding the first linear actuator to move to the first corrected stroke position and the second linear actuator to move to the second corrected stroke position to point the payload at the target along a line of sight vector without verifying the target pointing direction of the base when the first and second linear actuators are positioned to the respective first and second corrected stroke positions and without using a feedback to verify the base being at the target pointing direction when the first and second linear actuators are positioned to the respective first and second corrected stroke positions.