A number of satellite communication systems have been proposed using geosynchronous (GEO) satellites, as well as low earth orbit (LEO) constellations operating in the Ka-band and above. At these frequencies satellite networks are able to provide broadband services requiring wider bandwidth than the current services at C or Ku-band. As a consequence, some of the new services gaining momentum inc...

this paper presents the design procedure and implementation results of a proposed hardware which performs different satellite image compressions using fpga xilinx board. first, the method is described and then vhdl code is written and synthesized by ise software of xilinx company. the results show that it is easy and useful to design, develop and implement the hardware image compressor using ne...

This article presents a new technology for satellite orbit determination using a simple Global Positioning System (GPS) receiver (microGPS) with ultra-low cost, power, and mass. The capability of low-cost orbit determination with microGPS for a low Earth-orbiting satellite, Student Nitric Oxide Explorer (SNOE), is demonstrated using actual GPS data from the GPS/Meteorology (MET) satellite. The ...

Mobile satellite communication channels are characterized by long transmission delays, variation of these delays, high bit-error-rates, shadowing and the multipath e!ect which severely reduce the quality of video services. Error control techniques including feedback mechanisms, error concealment methods, forward error correction techniques and error resilience schemes are examined in this paper...

In the present work a new concept of satellite-based navigation system, which does not require on-board atomic references, is presented. This novel concept consists of a constellation of compact low-earth orbit positioning satellites that are equipped with on-board steerable clocks, i.e. voltage controlled crystal oscillator (VCXO). An appropriate ground-satellite synchronization network is res...

Current TCP protocols have low throughput performance in satellite networks mainly due to the e!ects of long propagation delays and high link error rates. TCP-Peach is a new congestion control scheme for satellite IP networks based on the use of low priority segments, called dummy segments. The sender transmits dummy segments to probe the availability of network resources. Dummy segments are tr...

An important factor in sustainable agriculture and economic management is to calculate areas under different crops that the inputs of agriculture connect to this topic. Planning of agricultural mechanization, fertilizer and pesticide requirements, pests and diseases control, estimates of agricultural production, income and tax and financial planning, all linked to the cultivated areas and estim...