Satelit Galileo
SATELLITE BASE POSITIONING - GPS COMPETITER Satelit Galileo merupakan sistem satelit navigasi global Eropa yang pertama dengan tingkat akurasi yang tinggi dan dikontrol dan dikelola oleh pihak sipil Uni Eropa. Adapun tujuan Uni Eropa untuk menciptakan satelit baru ini adalah untuk mengurangi ketergantungan terhadap pemakaian GPS dan untuk dapat bersaing dalam dunia persatelitan dengan negara-negara maju seperti Amerika Serikat. Sistem ini didesain untuk untuk memberikan posisi dan kecepatan tiga-dimensi serta informasi mengenai waktu secara kontinyu di seluruh dunia tanpa bergantung pada waktu dan cuaca kepada kepada banyak banyak orang secara simultan. simultan. Satelit ini masih baru dan mulai diluncurkan pada tahun 2005, dan akan beroperasi secara penuh pada tahun 2008. 2008 . Pada prinsipnya penentuan posisi dengan satelit Galileo hampir sama dengan penentuan posisi dengan GPS. Kedua satelit navigasi ini hanya berbeda pada spesifikasi dan kemampuannya. ————————————————————————————————— ———————————————-——————————————— Komponen Sistem Satelit Galileo Secara umum ada tiga komponen penyusun sistem Galileo yaitu komponen angkasa (space segment), komponen kontrol bumi (ground segment), dan komponen pengguna (user segment). Segmen angkasa Galileo terdiri dari 30 satelit, dimana terdapat 27 satelit yang aktif dan 3 satelit cadangan (spare) dalam Medium Earth Orbit (MEO) pada ketinggian 23600 km. Satelit akan melakukan perjalanan sepanjang tiga orbit sirkular pada inklinasi 56°. Dengan waktu orbit 14 jam, konfigurasi dari konstelasi akan menjamin sekurang-kurangnya 10 satelit yang kelihatan akan memberikan informasi posisi dan waktu untuk semua lokasi, termasuk daerah kutub. Wahana Satelit Galileo diharapkan akan dapat bertahan selama 10 tahun.
Segmen angkasa akan diatur lewat dua stasiun kontrol yang dipilih di suatu tempat di Eropa, yang didukung oleh 20 stasiun sensor Galileo (GSS). Pertukaran data antara stasiun kontrol dan satelit akan dikerjakan melalui stasiun penghubung khusus. Sebanyak 15 stasiun penghubung akan dipasang di sekitar permukaan bumi untuk memudahkan dalam hal transfer data. Sebagai komponen kontrol bumi (ground segment), stasiun kontrol akan bertanggungjawab memanajemen satelit, mengintegrasikan sinyal, dan sinkronisasi jam atom pada satelit. Segmen pengguna terdiri dari para pengguna satelit Galileo, baik di darat, laut, udara, maupun di angkasa. Dalam hal ini alat penerima sinyal Galileo diperlukan untuk menerima dan memproses sinyal -sinyal dari satelit Galileo untuk digunakan dalam penentuan posisi, kecepatan dan waktu. Komponen utama dari suatu receiver Galileo secara umum adalah antena dengan pre-amplifier, bagian RF dengan pengidentifikasi sinyal dan pemroses sinyal, pemroses mikro untuk pengontrolan receiver, data sampling dan pemroses data ( solusi navigasi ), osilator presisi , catu daya, unit perintah dan tampilan, dan memori serta perekam data. ————————————————————————————————— ———————————————Sinyal Satelit Galileo Satelit Galileo akan menstransmisikan 10 sinyal yang berbeda. Dari sini, 6 sinyal akan digunakan untuk keperluan sipil (Open Service) dan Safety of Life Service, 2 sinyal untuk keperluan komersial dan sisanya 2 untuk keperluan Public Regulated Service. Selain pelayanan navigasi dan transmisi waktu, Galileo akan menyediakan informasi mengenai akurasi dan status sinyal tersebut. ————————————————————————————————— ———————————————Tipe Receiver Satelit Galileo Mengenai receiver Galileo, belum ada keputusan akhir tentang spesifikasi dan kemampuan receiver Galileo melainkan sekarang sedang dikembangkan untuk dapat bersaing dengan GPS.
Analisis pasar memberikan klasifikasi pendahuluan tentang tipe receiver Galileo yaitu: Tipe konsumen, Tipe profesional, dan Tipe Safety of Life. Tipe konsumen sendiri terdiri dari dua jenis yaitu A1 dan A2. Jenis A1 berdiri sendiri yang merupakan receiver navigasi utama Galileo, dan A2 digunakan untuk bantuan komunikasi (NAV/COM). Tipe profesional terdiri dari empat jenis yaitu B1 (Single frequency ditambah Local Element (LE)), B2 (Dual frequency ditambah LE), B3 (Triple frequency ditambah LE), dan B4 (Single frequency ditambah bantuan komunikasi). Sementara itu Tipe Safety of Life terdiri dari dua jenis yaitu C1 dan C2. Jenis C1 merupakan receiver yang memiliki spesifikasi Dual frequency plus LE (+EGNOS) with integrity. Jenis C2 memiliki spesifikasi Triple frequency plus LE (+EGNOS) with integrity. ————————————————————————————————— ———————————————Kemampuan layanan Sistem Satelit Galileo Ada 5 macam layanan atau jasa yang rencananya akan diberikan sistem satelit Galileo ini, yaitu: 1) Pelayanan Terbuka (Open Service atau OS) OS ini adalah bebas dan menyediakan pelayanan seperti GPS tetapi dengan akurasi yang lebih tinggi. Dalam hal ini, ESA berperan aktif dalam mengintegrasikan Galileo dengan sistem GSM/UMTS. OS ini ditetapkan sebagai pasar sinyal besar-besaran untuk informasi waktu dan posisi yang tersedia dengan gratis. OS ini dapat diperoleh oleh semua orang yang dilengkapi dengan receiver tanpa pemberian hak. 2) Pelayanan Keselamatan Hidup (Safety of Life Service atau SLS) SLS ini akan digunakan untuk aplikasi transportasi yang mana dapat membahayakan hidup jika penampilan sistem navigasi menurun tanpa pemberitahuan dengan real-time. 3) Pelayanan Komersial (Commercial Service atau CS) CS ini diperuntukkan untuk aplikasi pasar (komersial) dengan pelayanan yang lebih tinggi dibandingkan dengan yang
ditawarkan oleh Open Service. Layanan ini tidak gratis melainkan user harus membayar jasa pelayanan artinya jika pengguna ingin mendapatkan informasi posisi dan waktu secara real-time, maka pengguna harus membayar sebesar biaya yang telah ditetapkan. 4) Pelayanan Publik (Public Regulated Service atau PRS) Galileo ini merupakan suatu system sipil yang memuat layanan pengontrolan akses untuk aplikasi pemerintahan. PRS ini akan digunakan oleh suatu badan atau instansi seperti kepolisisan dan departemen-departemen 5) Layanan Pencarian dan Pertolongan (Search and Rescue Service atau SAR) SAR ini memberikan kontribusi Eropa dalam dunia internasional dalam usaha pemberian bantuan dan pertolongan kemanusiaan. ————————————————————————————————— ———————————————Kelebihan dan Keuntungan Sistem Satelit Galileo Galileo ini merupakan satelit yang dirancang khususnya untuk keperluan non-militer. Bila dibandingkan dengan satelit navigasi lainnya seperti GPS dan GLONASS, satelit Galileo ini mempunyai beberapa keuntungan dan kelebihan antara lain: - Satelit Galileo didesain dan dikembangkan untuk aplikasi nonmiliter, sebaliknya GPS didesain terutama untuk aplikasi militer. - Galileo didasarkan pada teknologi yang sama seperti GPS dan menyediakan informasi posisi dan waktu dengan tingkat presisi yang lebih tinggi. - Galileo lebih dapat dipercaya meliputi suatu signal “pesan” yang memberitahu user dengan seketika apabila terjadi suatu kesalahan - Satelit Galileo terbuka dan meluas ke seluruh pasar yang meliputi seluruh dunia dan perusahaan-perusahaan komersil Eropa - Galileo memberikan pelayanan nyata bagi publik seperti pemberian garansi yang kontinyu yang ditetapkan untuk aplikasi khusus - Galileo telah menciptakan 140 000 job dan mampu menggerakkan pasar yang diperkirakan mencapai €9 billion per
tahun. Ini lebih rendah dibandingkan ketergantungan Eropa terhadap GPS untuk keperluan ekonomi. ————————————————————————————————— ———————————————Aplikasi Teknologi Satelit Galileo Sistem Satelit Galileo dibangun mirip dengan sistem GPS, oleh karenanya aplikasi dari sistem Galileo akan menyerupai aplikasi dari sateli GPS. Gambaran umum yang diberikan sistem satelit Galileo untuk bidang aplikasi diantaranya diperuntukan bagi kepentingan transportasi, keperluan penerbangan (aviation), aplikasi maritim, pekerjaan teknik sipil, perikanan, pertanian (precise farming), monitoring lingkungan. referensi waktu dan telekomunikasi. Bidang-bidang lainnya yang menjadi aplikasi sistem Galileo, sama halnya dengan sistem GPS yaitu: survai pemetaan, geodinamika, geodesi, geologi, geofisik, pemantauan deformasi, , dan bahkan juga bidang olahraga dan rekreasi
http://geodesy.gd.itb.ac.id/?page_id=502 http://www.esa.int/Our_Activities/Navigation/The_future_-_Galileo/What_is_Galileo
Survey BeiDou Navigation Satellite System is China’s global navigation satellite system which has been developed independently.The system’s target: maintain independence and keep the initiative in our own hands,keep open,compatible,stable and reliable on technology, offer global service, thereby accelerating the foundation of navigation satellite industrial chain,consummating the sustaining extending and guaranteeing system,expanding the range of application in the country's economic and social sector.
BeiDou Navigation Satellite System is composed of three parts: the space section, the ground section and the user section. The space section contains 5 geostationary orbit satellites and 30 nongeostationary orbit satellites. The ground section consists of a certan number of stations: including the main control stations, the injectionstations and the monitoring stations. And the user section includes terminators of BeiDou system,and some compatible with other navigation satellite system.
Service target The BeiDou Navigation Satellite System will provide global coverage with positioning, navigation and timing services, including two kinds of service modes: an open service and an authorized service. The open service is provided free of charge location, velocity and timing, with positioning accuracy of 10 meters, velocity accuracy of 0.2 meters / second and timing accuracy of 10 nanoseconds. The authorized service provides a more secure position, velocity, timing, and communications services as well as a higher level of integrity. In order to make BeiDou Navigation Satellite System work better for global service, strengthen compatiblityand interoperability between BeiDou and other countries’satellite navigation systems,and promote satellite positioning, navigation and timing service application, China is willing to cooperate with other countries in developing satellite navigation industry.
Development plan Now, China is implementing the BeiDou Navigation Satellite System. In accordance with the construction plan, the initial satellite navigation system will provide coverage in the Asia-Pacific
region with positioning, navigation, timing, and short-message communication service capabilities. The system isdesigned to provide global coverage around 2020.
Development Process Navigation satellite system is an important infrastructure of space information.China attaches great importance to the construction of such a system, and has been searching and developing the system which possesses independent intellectual property rights for years. In 2000, China set up a BeiDou navigation test system ,which made China the third country in the world capable of developing such a system on its own since the United States and Russia.The test system has been widely applied in areas including communication and transportation, forest fire prevention, disaster forecast, public security and more
，
making remarkable benefit in social, economic
aspects. In the 2008 Beijing Olympic Games and the Wenchuan earthquake in particular, this China-made system played an important role. To further serve the nation’s constructionand development,and meet the needs of the world, China recently put into effect the construction of BeiDou Navigation Satellite System.
COMPASS The BeiDou Navigation Satellite System (BDS), also known as BeiDou-2[1], is China’s second-generation satellite navigation system[1][2] that will be capable of providing positioning, navigation, and timing services to users on a continuous worldwide basis [3]. Although the evolution of its regional navigation system towards a global solution started in 1997, the formal
approval by the Government of the development and deployment of BDS System was done in 2006 and it is expected to provide global navigation services by 2020, similarly to the GPS, GLONASS or Galileo systems.[1] As of December 2011, the BeiDou system was officially announced to provide Initial Operational Service providing initial passive positioning navigation and timing services for the whole Asia-Pacific region with a constellation of 10 satellites (5 GEO satellites and 5 IGSO satellites)[4][2]. During 2012, 5 additional satellites (1 GEO satellites and 4 MEO satellites) were launched increasing to 14 the number of satellites of the constellation. Until 2020, the system is going to launch the remaining satellites and evolve towards global navigation capability. [5][4].
The BeiDou Navigation Satellite System (BDS), also known as BeiDou-2[1], is China’s second-generation satellite navigation system[1][2] that will be capable of providing positioning, navigation, and timing services to users on a continuous worldwide basis [3]. The first and second generation of BeiDou receivers are already available, including the combination of GPS and BeiDou systems - currently limited to the available regional services - with already over a thousand users.
BeiDou Receiver
The BeiDou User Segment consists of Beidou user terminals[4]. The first user terminals appeared in 2009 based in ASIC and comprising already GPS integration[5].
Particularities Each GNSS system uses a specific Reference Frame; although a multi-constellation receiver is able to convert all information to the same common frame, a BeiDou-only receiver uses the China Geodetic Coordinate System 2000 (CGCS2000), consistent with the International Terrestrial Reference System (ITRS). In an analogous way, each system has its own time reference defined by the respective control segments; the time reference for BeiDou is called “BeiDou Time” (BDT) and it is aligned with UTC. Each GNSS System transmits its own navigation message, defined in the respective Signal In Space Interface Control Document, SIS ICD, and whose content is used by receivers to compute their positions. The first version of the SIS ICD for BeiDou B1I open service signal on 1561.098 MHz was released December 27 at a news conference held in Beijing by the Chinese State Council Information Office [6]. GNSS signals modulation, structure, navigation message contents and formats are often different among signals from the same system and from
different systems. Most of these characteristics are easily implemented at the receiver (e.g. requiring only “software modifications”, such as the use of different PRN codes or the ability to cope with different message structures). The main difference among GNSS receivers falls into the specific characteristics that have impact at RF level, such as the Multiple Access Techniques employed. BeiDou (as GPS and Galileo) uses CDMA techniques allowing a simpler RF module (than for example GLONASS), since all signals in the same frequency band have a common carrier. Nevertheless, BeiDou supports a regional short message service, which allows the user to send information to the stations. This additional communication link adds complexity to the receiver, and therefore potentially higher costs. It should be noted that the current trend consists on facilitating the access of each system to the receivers, i.e. fomenting multi-constellation receivers. Hence, most discussions and agreements among the systems’ responsibles are conducted in the sense of taking this effort out of the user segment, focusing on compatibility andinteroperability aspects in the system design
The BeiDou Navigation Satellite System (BDS), also known as BeiDou-2[1], is China’s second-generation satellite navigation system[1][2] that will be capable of
providing positioning, navigation, and timing services to users on a continuous worldwide basis [3].
Contents [hide]
1 2 3 4 5
BeiDou Roadmap BeiDou Status BeiDou General Services International Context References
BeiDou Roadmap The BeiDou system is planned to be developed and deployed in three phases [4]:
Phase 1 (2003+) Phase 1 consists of an experimental regional navigation system, BeiDou-1, which provided active navigation service.
Phase 2 (2012+) BeiDou-2 consists of a reduced satellite constellation and provides open service over China. This phase aims at deploying a system with passive positioning and timing capability over a regional area. Phase 3 (2020+) By 2020, BeiDou would reach full operational capability with a Walker constellation of 27 MEOs plus 5 GEOs and the existing 3 IGSOs satellites of
the regional system[1]. BeiDou would provide global navigation services, similarly to the GPS, GLONASS or Galileo systems.[1]
BeiDou Status By December 2011, the BeiDou system went into operation on a trial basis providing initial passive positioning navigation and timing services for the whole Asia-Pacific region with a constellation of 10 satellites (5 GEO satellites and 5 IGSO satellites)[5][6] and the Initial Operational Service was declared officially available. During 2012, four launches where made in February, April, September and October, placing in orbit two adittional GEO and four MEO satellites in-line with the objective of expanding the service area to Asian-Pacific users and improving service performance (positioning accuracy better than 10 meters)[7]. The constellation is currently composed by 6 GEO + 5 IGSO + 4 MEO which corresponds to 15 operational satellites of the 35 planned. Furthermore, the first version of the SIS ICD for the BeiDou B1I open service signal was released on the 27 th December 2012 at a news conference held in Beijing by the Chinese State Council Information Office[8], where it was also announced that the
english name of the system was now to be replaced with BeiDou Navigation Satellite System, instead of its translation, BeiDou.
BeiDou General Services The future BeiDou is expected to support two different kind of general services: RDSS and RNSS. In the Radio Determination Satellite Service (RDSS) , the user position is computed by a ground station using the round trip time of signals exchanged via GEO satellite. The RDSS Long term feature further includes [9]:
Short message communication (guaranteeing backward compatibility with BeiDou-1)
Large volume message communication Information connection Extended coverage
The Radio Navigation Satellite Service (RNSS) is very similar to that provided by GPS and Galileo and is designed to achieve similar performances.
International Context The Chinese Government considers satellite navigation as strategic in the new generation information technology, and encourages
international cooperation to ensurecompatibility and interoperability with other navigation systems [7]. http://www.navipedia.net/index.php/BeiDou_Future_and_Evolutions http://www.unavco.org/help/glossary/glossary.html
