A Far Range Image Processing Method for Autonomous Tracking of an Uncooperative Target
This paper proposes an image processing method for far range rendezvous. A target spacecraft at distances up to $30$~km is tracked from camera images. The method is based on linking bright, connected sets of pixels over sequences of images. Stars and the target spacecraft are identified by using a star catalog and performing motion segmentation. The algorithm is illustrated in detail and 
%the visibility of stars and of the target are analyzed which is a prerequisite to perform far range image processing. Further, 
results of a flight experiment called ARGON are presented. The experiment took place in the extended phase of the PRISMA mission. The image processing method was employed and a successful rendezvous from $30$~km to $3$~km was accomplished using optical navigation.
Relative Angles-Only Navigation and Pose Estimation for Autonomous Orbital Rendezvous
This paper explores the potential of using angles-only navigation to perform various autonomous orbital rendezvous and close proximity operations. A 32-state extended Kalman filter is developed that processes angular measurements from an optical navigation camera along with gyro and star tracker data to estimate the inertial position, velocity, attitude, and angular rates of both a target and chaser vehicle. The target satellite is assumed to be passive while the chaser may perform a variety of autonomous rendezvous and close proximity maneuvers. The navigation filter’s performance is evaluated and tested by running a coded prototype in a closed loop 6 degree-of-freedom simulation tool containing the various sensors, actuators, GN&C flight algorithms, and dynamics associated with a simple rendezvous scenario. The analysis performed for this study uses standard Monte-Carlo techniques. These results not only include the navigation errors associated with implementing an angles-only navigation scheme, but they also reveal the dispersions from the nominal trajectory associated with this particular technique in a closed-loop GN&C setting. The rendezvous scenario duplicates a similar close proximity scenario analyzed using linear covariance analysis. Both methods are compared to add validity to the results and highlight the advantages and potential of each approach for autonomous orbital rendezvous and close proximity operation analysis.
DESIGN CONSIDERATION TO PPM KLYSTRONS FOR INDUSTRIAL LINAC
Toshiba has been developing the C-band and X-band Periodic Permanent Magnet (PPM) focused klystron in collaboration with KEK and manufactured prototypes for the JLC project. [1] The PPM klystron has an advantage to enhance the total efficiency as a result of eliminating the electric power for the focusing magnet. From experience on the development the PPM focused klystrons for the JLC project, we plan to apply the PPM focused klystron to the medical and industrial linac. The periodic magnet focusing scheme has some technical difficulties such as stop band voltage. To design the PPM klystron for the medical and industrial linac, it is necessary to give heed to electron beam instability; so that the tube parameters of the PPM focused klystrons have some constraints. The size of the accelerator system is substantially reduced if a PPM focused klystron is used. The majority of medical and industrial linacs use frequencies of S-band range. We discuss the availability of the S-band PPM focused klystron in this paper.