The NASA Marshall Space Flight Center has developed a synchronized subsystem for use in an automated docking system for docking a chase vehicle with a target vehicle. The chase vehicle is provided with a video camera for feeding digitized frames to an image processing unit, which feeds signals to a control circuit. The control circuit turns on the video camera to digitize a background frame that will include the target vehicle. After the camera grabs the background frame the control circuit turns on a light, which is carried on the chase vehicle and aimed at the target vehicle, and signals the video camera to digitize a foreground frame. A light sensing circuit on the target vehicle receives the light from the chase vehicle connects a power supply to lights on the target vehicle such that when the foreground frame is digitized the lights on the target vehicle will show in the foreground frame. The image processing unit subtracts the background frame from the foreground frame and provides a docking signal.

Benefits

Potential Commercial Uses

The Technology

A system of lights, carried by a target vehicle, includes lights mounted on a base plane at a spaced distance apart. A post located between the lights projects forward of the base plane and carries a third light mounted on the end of the post. A power supply on the target vehicle is connected through a light sensing circuit to power the lights when the light sensing circuit senses light above a certain threshold or intensity. If desired, the light may be modulated at a predetermined frequency, with the light sensing circuit being responsive to the modulated light. A video camera carried by a chase vehicle to be docked with the target vehicle provides video frames of the target vehicle and its lights. The video camera feeds signals to an image processing unit. The image processing unit sends docking or station keeping signals to a software processor, which controls a docking process controller. The docking process controller operates thruster hardware. The image processing unit also operates a control circuit that controls the video camera and a light positioned on the chase vehicle to be directed at the target vehicle. At a signal from the image processing unit the control circuit signals the video camera to digitize a background video frame with the lights off. After the background frame is digitized the control circuit turns on the light carried by the chase vehicle and signals the video camera to digitize a foreground frame. The light is sensed by the light sensing circuit on the target vehicle to turn on the lights mounted on the base plane and the post. The foreground video frame digitized by the camera will show the illuminated lights on the target vehicle. The background frame is subtracted from the foreground frame by the image processing unit to provide a docking or station keeping signal that is fed to the software processor. This process is continued until docking is completed or it is no longer desired to keep the chase vehicle at a particular relationship to the target vehicle.

Patent Number

6,227,495

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