نتایج جستجو برای: satellite antenna
تعداد نتایج: 123616 فیلتر نتایج به سال:
The reconfigurable antenna based on RF-MEMS is hot researching direction in recent years,it can change electric parameters,such as radiation pattern,working band, input impedance, polarization diversity ,and so on. reconfigurable antenna of multi-band and multi-mode can replace multiple antennas based on one vehicle,decreases the developing price,size and weight of antennas,which is very import...
A method for the estimation of the phase center variations of GPS satellite antennas using global GPS data is presented. First estimations have shown an encouraging repeatability from day to day and between satellites of the same block. Thus, two different satellite antenna patterns for Block II/IIA and for Block IIR with a range of about 4 cm and an accuracy of less than 1 mm could be found. T...
In June, 2010 the German SAR satellite TanDEM-X (TerraSAR-X-Add-on for Digital Elevation Measurements) will be launched. Together with TerraSAR-X, launched June 15, 2007, it will form the first spaceborne bistatic SAR platform. Usually one of the satellite is transmitting (active satellite), while both are receiving. As both satellites fly in a helix orbit constellation, during a recording a sa...
We analyzed one year of DORIS data to estimate daily corrections to the mean locations of the satellite antenna phase centers. For each DORIS satellite, we looked for possible biases, discontinuities, trends or annual signals. All SPOT satellites show very similar patterns, which are characterized by a significant constant bias of about 20 mm in the cross-track direction as well as a clear annu...
A satellite antenna alignment technique is proposed to ensure terrestrial service quality for users. The antenna bore sight orientation is calculated directly from measured data acquired from general ground receivers, which intercept the communication radio waves from any position on the earth’s surface. The method coordinates the satellite pointing parameters with signal strength at the receiv...
The positioning tecnique of global navigation satellite systm (GNSS) has become mature and also been applied to a variety of navigation vehicles, whether it be the application to ground vehicle ot aircraft. Nevertheless, the precision of GNSS is susceptible to intentional or unintentional factors such as interference or jammer, etc. The influences range from minor effect like the positioning pr...
Satellite Communication Systems are beneficial in providing communication services to vast regions especially where the adequate infrastructure for communication may not be constructed. Wireless communication is one of the fastest growing fields in the engineering world. Introduction on adaptive antenna array is described in this paper. Linear adaptive algorithm LMS (Least mean square) is used ...
Scintillation is a transmission impairment. The Received Satellite signals degradation due to the scintillation on space to earth link in tropical region. This proposed work goal is to find the performance evaluation of scintillation in clear sky conditions. To estimate and compare the statistic of atmospheric scintillation based on the parameters in ITUR model. To evaluate Atmospheric Amplitud...
The Microstrip antenna has been commercially used in many applications, such as direct broadcast satellite service, mobile satellite communications, global positioning system, medical hyperthermia usage, etc. The patch antenna of the size reduction at a given operating frequency is obtained. Mobile personal communication systems and wireless computer networks are most commonly used nowadays and...
Deployment of a satellite borne, steerable antenna array with higher directivity and gain in Low Earth Orbit makes sense to reduce ground station complexity and cost, while still maintaining a reasonable link budget. The implementation comprises a digitally beam steerable phased array antenna integrated with a complete system, comprising the antenna, hosting platform, ground station, and aircra...
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