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Abderrahmane L.H.,Algerian Space Agency ASAL
IET Communications | Year: 2013

The main aim of this work is to find a way to improve a turbo code performance by designing a new interleaver structure based on the cross entropy (CE). The goal is to compare the performance of the CE method to a more popular interleaver such as the dithered golden interleaver. This study describes the performance of the turbo code - binary phase shift keying (BPSK) modem which was designed at the Instrumentation Division, Centre of Space Techniques. The simulation results are detailed in terms of the optimal solution observed along with the estimated bit-error rate against Eb/N0. The authors compare the performance of turbo codes for different interleaver sizes and different number of iterations (resulting trade-off curves) assuming two channel types (Gaussian and Rayleigh channels). For the simulated cases of the interleavers, good performance is obtained with the CE interleaver when transmitting data both in short block length (N = 400 bits), and long block length (N = 1024). © The Institution of Engineering and Technology 2013. Source


Jason S.,Surrey Satellite Technology | Da Silva Curiel A.,Surrey Satellite Technology | Liddle D.,Surrey Satellite Technology | Chizea F.,National Space Research and Development Agency NASRDA | And 7 more authors.
Advances in Space Research | Year: 2010

This paper focuses on ways in which space is being used to build capacity in science and technology in order to: Offer increasing support for national and global solutions to current and emerging problems including: how to improve food security; resource management; understanding the impacts of climate change and how to deal with them; improving disaster mitigation, management and response.Support sustainable economic development. We present some of the experiences, lessons learned and benefits gained in capacity building projects undertaken by Surrey Satellite Technology Ltd. and our partners from developing and mature space nations. We focus on the Turkish, Algerian and Nigerian know-how and technology transfer programmes which form part of the first Disaster Monitoring Constellation (DMC) in orbit. From the lessons learned on Surrey's know-how and technology transfer partnership programmes, it is clear that space technology needs to be implemented responsibly as part of a long-term capacity building plan to be a sustainable one. It needs to be supported with appropriate policy and legal frameworks, institutional development, including community participation, human resources development and strengthening of managerial systems. In taking this on board, DMC has resulted in a strong international partnership combining national objectives, humanitarian aid and commerce. The benefits include: Ownership of space-based and supporting ground assets with low capital expenditure that is in line with national budgets of developing nations.Ownership of data and control over data acquisition.More for the money via collaborative consortium.Space related capacity building in organisations and nations with the goal of sustainable development.Opportunities for international collaboration, including disaster management and relief. © 2010 COSPAR. Published by Elsevier Ltd. All rights reserved. Source


Abderrahmane L.H.,Algerian Space Agency ASAL | Bacha M.,Algerian Space Agency ASAL
Proceedings - 2014 International Conference on Control, Decision and Information Technologies, CoDIT 2014 | Year: 2014

The main aim of this work is to find a way to replace the current coding scheme implemented on AlSat-2; the second earth observation Algerian Microsatellite (2.5 m of resolution), to be implemented on the future high resolution earth observation Algerian Microsatellite, by the discovered Turbo Codes. This paper describes the performance of the Turbo Code - Binary Phase Shift Keying (BPSK) Modem which was designed at the Centre of Satellite Development (CDS). This proof-of-concept modem is the outcome of a research and development (R&D) project entitled 'Design of a smart adaptive communication system for the future satellite communication systems'. The major technical contribution of this work is the new interleaver design using chaotic sequences to produce the dither in the golden interleaver. We compare the performance of Turbo codes for different interleaver sizes and a number of iteration equal to five with the performance of the industry standard rate 1/2, constraint length (K) seven, convolutional code. As example and for practical considerations, the interleaver length is fixed to be equal to 1024. To achieve a bit error rate (BER) of 10-5, a gain of about 3dB is reached when we replace the current scheme (convolutional encoder) with the suggested Turbo encoder. © 2014 IEEE. Source


Boukerch I.,Algerian Space Agency ASAL | Hadeid M.,Oran University of Science and Technology - Mohamed Boudiaf | Mahmoudi R.,Algerian Space Agency ASAL | Takarli B.,Algerian Space Agency ASAL | Hasni K.,Algerian Space Agency ASAL
Journal of the Indian Society of Remote Sensing | Year: 2015

The co-registration of panchromatic and multispectral images is an important task to obtain a good pan sharpened images. Generally, co-registration can be realized by using image-based or geometry-based methods. The geometry-based method necessitates the understanding and the modelling of the imaging process. This paper describes a method for co-registration of panchromatic and multispectral images from ALSAT-2A the first high resolution Algerian satellite. This method, based on the analysis of the metadata provided by the considered sensor, uses the time dependant collinearity condition for rigorous camera modelling. Three experiments, based on ALSAT-2A images, are performed. The first experiment deals with calculating the exterior orientation parameters (EOP) using the panchromatic image and applying them for georeferencing the multispectral image. In the second experiment; the panchromatic image is georeferenced by applying the model EOP calculated from the multispectral image. The third experiment consists in using both images in a bundle adjustment procedure for a higher accuracy. Sub pixel positioning accuracy can be obtained using the model calculated using the panchromatic image only. © 2014, Indian Society of Remote Sensing. Source

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