The use of regional-coverage satellite constellations is on the rise, urging need for an optimal constellation design method complex regional coverage. Traditional are often designed continuous global coverage, and few existing methods lead to suboptimal solutions periodically time-varying or spatially varying requirements. This paper introduces a new general approach pattern that satisfies such To this end, circular convolution nature repeating ground-track orbit common formalized....

The recent growing trend to develop large-scale satellite constellations (i.e., mega-constellations) with low-cost small satellites has brought the need for an efficient and scalable maintenance strategy decision plan. Traditional spare strategies cannot handle these mega-constellations due their limited scalability in number of and/or frequency failures. This paper proposes a novel using inventory management approach. It considers set parking orbits at lower altitude than constellation...

A state transition matrix for formation flying in eccentric orbits is considered this paper. The relative motion of the obeys Tschauner–Hempel equations, which are extended presence a J2 perturbation. Furthermore, transitionmatrix equations J2, and it demonstrated that becomes solution equations. Because only uses osculating orbital elements initial does not use mean elements, an analytical treatment possible. When first-order term errors sometimes become large compared with...

The concept and the current status of a newly developed PEM pattern inspection system are presented. An image-processing technique with learning functions to enhance system's detection capability is investigated. Highly accelerated electrons employed here in electron-optics function as an enabler improve image resolution transmittance system, acquire contrast 0.5 half pitch (hp) 64 nm lines space pattern. This process also results formation electron more than 3000 per pixel on sensor. was...

In order to realize EUV mask pattern defect inspection in 16nm node, we have developed new optics on a novel projection electron microscopy (PEM) and system with the handling imaging units, e.g., high precision stage, an detector, processing system, so. on. This enables us make resolution speed as compared conventional DUV EB systems. The PEM comprises exposure beam (EOs). is based design concept meet required progress for 1Xnm current 2Xnm node; employs techniques achieve features:...

Capturing a target by robot hand in space inevitably causes impulsive forces on the contact points. Such possibly give undesirable effects to both spacecraft. The authors' purpose is study relationships between initial relative velocities of and resulting impulse. authors consider servo stiffness desired joint rates for manipulator control. Using Laplace transformation, estimate impulse with these taken into consideration. From estimations, it shown that increases effective moment inertia...

Arm path planning of a space robot with angular momentum is considered in this paper. A changes its attitude by the arm motion and has possibility to reduce change. method where final satellite becomes same as initial one proposed. The derives an approximate first based on change when moves along infinitely small closed curve then modifies Newton method. amplitude decreases magnitude momentum, which shows that proposed utilizes effectively.

The authors describe two design techniques for slanted-finger interdigital transducers (IDTs) which could not be designed using conventional techniques. One technique provides a large stopband attenuation: individual fingers or groups of slanted-fingers are withdrawn from the selected portions IDT. other realizes nonlinear phase response: center-to-center distance between transmitting and receiving ITDs is varied along axis normal to surface acoustic wave (SAW) propagation axis. Two examples...

A method of controlling the attitude a space robot using its arm motion is considered. The proposed can make large change by cyclic arm. First path planned based on small when moves along closed path. Then modiŽ ed feeding back error during motion. Numerical simulations have been executed to verify feedback law model with an six degrees freedom.

This paper focuses on the R-bar and V-bar approaching methods as viewed from various aspects such control, orbit dynamics, abort characteristics, relative navigation. Differences in combination of outputs Rendezvous LOS Sensor other attitude sensors are clarified by analytical derivation their kinematical relationships, which provides a basis for control. Following that, based it is shown that has benefits holding, quick approach recovery. Finally, positional accuracy direction estimated GPS...

We have developed a star sensor as an experimental device onboard the SERVIS-1 satellite launched in October 2003. The in-orbit data verified its fundamental performance. One of advantages our is that baffle has small length 120 mm instead 182 conventional two-stage design. key concepts for light shielding are total internal reflection phenomena inside nearly half sphere (NHS) lens and scattering control by gloss black paint. However, undesirable background noise sun outside field view (FOV)...

It is possible to utilize a surface-acoustic-wave (SAW) interdigital transducer (IDT) with large number of electrodes as resonator-a SAW resonator. Band-elimination filters and bandpass narrow bandwidth have been developed employing resonators.

We have developed a light-shielding technique for star sensor that can shorten the baffle length. achieved length of 120 mm, two-thirds conventional two-stage baffle. The key idea is first lens imaging optics designed as near-hemispherical (NHS) work an angle filter; high-incidence-angle rays are not permitted to be transmitted but low-incidence-angle from stars be. A system with new onboard SERVIS-1 satellite was launched in October 2003 experimental device. Though in-orbit data verified...

F ORMATION flying, in which several spacecraft maintain their relative positionswith each other, has attractedmuch attention recent years, and various missions for Earth astronomical observations using flying formation have been proposed [1,2]. A that moves a reference orbit is called the chief spacecraft, with deputy spacecraft. The equations of motion circular are given by well-known Hill–Clohessy–Wiltshire (HCW) [3]. HCWequations set linearized describe themotion to under assumption...

The recent status of a newly developed PEM pattern inspection system for hp 16 nm node defect detection is presented. A die-to-die sensitivity the developing also investigated. programmed mask was used demonstrating performance system. Defect images were obtained as difference by comparing "withdefects" to "without-defects". This image-processing inspection. Captured extrusion and intrusion defects in 64 L/S detection. 12 sized defect, that smaller than our target size requirement,...

High-sensitivity and low-noise extreme ultraviolet (EUV) mask pattern defect detection is one of the major issues remaining to be addressed in device fabrication using lithography (EUVL). We have designed a projection electron microscopy (PEM) system, which has proven quite promising for half-pitch (hp) 16-nm node hp 11-nm inspection. The PEM system was integrated into inspection sensitivity evaluation. To improve performance patterned toward EUVL mask, signal characteristics, depend on...

A surface-acoustic-wave (s.a.w.) band-elimination filter has been developed employing s.a.w. resonators composed of interdigital transducers with a large number electrodes, exhibiting more than 80 dB stopband rejection passband attenuation less 1 dB.

Multiple beams are formed around an optical axis and scanned on a specimen. Secondary electrons (SEs) emitted from the points accelerated by electrostatic objective lens deflected E cross B (E×B) beam separator to secondary-electron detector. By scanning over 80 nm line & space pattern with four beams, Scanning Electron Microscopy (SEM) images obtained. From these SEM it is seen that there no problem cross-talk neighboring in multiple-beam where plural detectors. The emittance brightness...

Feedforward control with a parameter estimation law for an artificial satellite antennas or manipulators is presented. The proposed method utilizes the linearity of unknown parameters on angular momentum. It possible to append capability by adding few terms conventional feedforward control. A compensation time delay in velocity loop reaction wheels also proposed, and its effects results are analyzed. analytical coincide well simulation results, expressed quantitatively. /«>, ke R3xl hce # 3xl