three-dimensional position measurements by global positioning system (gps) provide purely geometrical estimate of low earth orbiters (leos) positions. it provides uninterrupted tracking of the leos in three spatial dimensions or the so-called kinematic orbit. this solution relies heavily on the observations. high frequency observation noise, outlying observations and low redundancy number of me...

The basic free-space optical communication system includes at least two satellites. To communicate between them, the transmitter satellite must track the beacon of the receiver satellite and point the information optical beam in its direction. Optical tracking and pointing systems for free space suffer during tracking from high-amplitude vibration because of background radiation from interstell...

This paper presents a realization of a simple antenna system for land vehicle satellite communication that is tested in experiments conducted on the Engineering Test Satellite-VIII (ETS-VIII). The developed antenna system which was mounted onto a vehicle roof is compact, light weight with simple satellite-tracking operation. In order to realize compact antennas, an onboard-power divider and swi...

small satellite-based tracking system that is light enough to be carried on birds was developed in the 1980s at the Applied Physics Laboratory. A new, more capable generation is now under development that will contain, in addition to the Argos tracking platform transmitter terminal, a global positioning system receiver and a complement of advanced sensors. The sensors may include a digital audi...

Introduction: In external beam radiotherapy each effort is done to deliver 3D dose distribution onto the tumor volume uniformly, while minimizing the dose to healthy organs at the same time. Radiation treatment of tumors located at thorax region such as lung and liver has a challenging issue during target localization since these tumors move mainly due to respiration. There are...

Satellite-based tracking of migratory waterfowl is an important tool for understanding the potential role of wild birds in the long-distance transmission of highly pathogenic avian influenza. However, employing this technique on a continental scale is prohibitively expensive. This study explores the utility of stable isotope ratios in feathers in examining both the distances traveled by migrato...

This paper presents a satellite tracking method based on optical celestial images. The proposed method is composed of two acquiring modes that are called Sidereal Stare Mode (SSM) and Track Rate Mode (TRM). To track the unknown satellites, first of all the entire of the sky is observed and the primary knowledge of the satellite location is predicted in SSM. Then, the measured pointing data is c...

This paper proposes an optimal algorithm for distributed orbit determination by using discrete observations provided from multiple tracking stations in a connected network. The objective is to increase the precision of estimation by communication and cooperation between tracking stations in the network. We focus on the dynamical approach considering a simplified Low Earth Orbital Satellite mode...