The Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) nighttime visible channel was designed to detect earth–atmosphere features under conditions of low illumination (e.g., near the solar terminator or via moonlight reflection). However, this sensor also detects visible light emissions from various terrestrial sources (both natural and anthropogenic), including l...

The paper proposes a maximum likelihood sequence estimator (MLSE) receiver for satellite communications. The satellite channel model is composed of a nonlinear traveling wave tube (TWT) amplifier followed by a multipath propagation channel. The receiver is composed of a neural network channel estimator (NNCE) and a Viterbi detector. The natural gradient (NG) descent is used for training. Comput...

The performance of the Multicast Dissemination Protocol (MDP) in a simulated satellite channel is investigated. The environment that is modeled is that to be expected in a small satellite communications environment including channel errors and link interruptions. The satellite link is simulated with a channel environment simulator. The performance of MDP is compared with file transfer protocol ...

Satellite ground track display computer program is designed and implemented for the KOMPSAT-2 mission operations. Digitized world map and detailed Korean map is realized with zoom and pan capability. The program supports real-time ground trace and off-line satellite image planning on the world map. Satellite mission timeline is also displayed with the satellite ground track for the visualized m...

The Ethiopian development plans have dealt with education sector as a key strategic pillar. There have been a lot of educational efforts. Especially to cope with lack of qualified teachers, lack of good teaching models, and remote rural regions separated from educational benefits, Ethiopian Ministry of Education has made efforts in utilizing educational media such as satellite TV program for im...

Hybrid satellite-terrestrial networks are becoming increasingly popular for asymmetric multimedia services such as file transfer and database services. This paper presents an adaptive error control (AEC) protocol for the hybrid network, in which the transmitter uses a combination of automatic repeat request (ARQ) over terrestrial links and forward error control (FEC) scheme with adaptive code r...

The objective of our paper is to improve efficiency (in terms of throughput or system capacity) for mobile satellite communications. In this context, we propose an enhanced Hybrid Automatic Repeat reQuest (HARQ) for delay tolerant services. Our proposal uses the estimation of the mutual information. We evaluate the performance of the proposed method for a land mobile satellite channel by means ...

This paper derives a physicalstatistical land mobile-satellite/HAP propagation channel model that can predict joint statistical time series and power-spatial-delay profile data in a multi-antenna mobile, multi-satellite scenario, and is compared with published measurement data. The model is then used to estimate the required satellite and HAP antenna separation to achieve an uncorrelated Satell...