In this work we describe a method to handle curved orbits in wavenumber domain focusing algorithm for high-resolution SAR data acquired by Low Earth Orbit satellites using spotlight mode. The standard wavenumber domain focusing algorithm make assumptions that start to be invalid when applied to high-resolution spotlight SAR data acquired in spaceborne low Earth orbit (LEO) configurations. The a...

In this paper the problem of sending a spacecraft from Low Earth Orbit (LEO) to the Moon with minimum fuel consumption is considered. It is assumed that the "Two-Body model" approximation is valid in all phases of the mission and that the final orbit around the Moon is polar. The first part deals with impulsive maneuvers, and obtain a set of values for fuel expenditure and trip time for several...

Low-Earth-Orbit satellite access network (LEO-SAN) can realize real-time and three-dimensional broadband on the earth anywhere any time. It has become a major development trend of Internet mobile communication networks, attracted more attention research from academia industry. LEO satellites achieve global coverage through giant constellations. Compared with medium- high-orbit satellites, have ...

This work is aimed at investigating the use of Multi Carrier CDMA (MC-CDMA) techniques in variable bitrate transmission over low-earth-orbit (LEO) satellite channels by means of realistic simulations. It is known by literature that MC-CDMA techniques are much more resilient with respect to multi-user interference effects in multipath fading channels than single-carrier DS/CDMA ones. Moreover, M...

In resent years ANN is widely reported for modeling in different areas of science including electro chemistry. This includes modeling of different technological batteries such as lead acid battery, Nickel cadmium batteries etc. Lithium ion batteries are advance battery technology which satisfy most of the space mission requirements. Low earth orbit (LEO)space craft batteries undergo large numbe...

Low-Earth Orbit (LEO) satellite systems are intended to have an important part of the future generation of mobile telecommunication systems. They aim to provide di erent services to various populations of users. Each class of users requires a certain Quality of Service (QoS) and thus a given part of the shared channel resource. In this paper, LEO satellite systems based on an earthxed cell conc...

Due to population distribution and economic flourish diversity, the low earth orbit (LEO) satellite network carries unbalanced traffic load, which leads that parts of satellite links are congested while others are underutilized. Furthermore, the congested inter-satellite links result in high queuing delay and packet dropping ratio. To ensure an intelligent scheduling of traffic over entire sate...

This paper presents an adaptive forward error correction (AFEC) protocol that provides a reliable communication service for real-time trafflc over low-earth orbit (LEO) satellite networks. In time-varying wireless links, such as LEO satellite networks, a reliable channel estimation scheme with an appropriate code selection technique is essential for adaptive error-control systems. This paper pr...

A radio frequency (rf) inductively coupled plasma apparatus has been developed to simulate the atomic oxygen environment encountered in low Earth orbit (LEO). Basing on the novel design, the apparatus can achieve stable, long lasting operation, pure and high density oxygen plasma beam. Furthermore, the effective atomic oxygen flux can be regulated. The equivalent effective atomic oxygen flux ma...