1

MOHAMMAD NORHERMAN ZULKFLI 01PUT11F1029MOHD SYAHIR MOHD HADURI 01PUT11F1020HAZIM HUSAINI MOHD FAHAMEE 01PUT11F1026NOR HIDAYAH NASRI 01PUT11F1017SARAH NADEHA SAMAD 01PUT11F1001HAFIZAH RASOL@MAT RASOL 01PUT11F1027

C 4344 - UKUR KADASTER 4PUAN NOORIZAWATY BINTI YUSUFF

GLOBAL POSITIONING SYSTEM (GPS)

2

Introduction

• The current global positioning system (GPS) is the culmination of years of research and unknown millions of dollars.

• Navigational systems have been and continue to be developed and funded by the U.S. government.

• The current system is managed by the U.S Air Force for the Department of Defense (DOD).

• The current system became fully operational June 26, 1993 when the 24th satellite was lunched.

• While there are millions of civil users of GPS worldwide, the system was designed for and is operated by the U. S. military.

• GPS provides specially coded satellite signals that can be processed with a GPS receiver, enabling the receiver to compute position, velocity and time.

• A minimum of four GPS satellite signals are required to compute positions in three dimensions and the time offset in the receiver clock.

• Accuracy and precision of data increases with more satellites.

Pengenalan

• Sistem penentu kedudukan global (GPS) yang kemuncak semasa tahun penyelidikan dan berjuta-juta dolar yang tidak diketahui.

• Sistem navigasi terus dibangunkan dan dibiayai oleh kerajaan Amerika Syarikat (AS).

• Sistem semasa yang diuruskan oleh Tentera Udara Amerika Syarikat untuk Jabatan Pertahanan (DOD).

• Sistem semasa beroperasi sepenuhnya pafa 26 Jun1993• Walaupun terdapat berjuta-juta pengguna sivil GPS di seluruh

dunia, sistem ini direka dan dikendalikan oleh tentera AS.• GPS menyediakan isyarat yang dikodkan khas satelit yang boleh

diproses dengan penerima GPS, yang membolehkan penerima untuk mengira kedudukan, halaju dan masa.

• Sekurang-kurangnya empat isyarat satelit GPS diperlukan untuk mengira kedudukan dalam tiga dimensi.

• Ketepatan dan ketepatan data yang meningkat dengan satelit yang lebih.

3

4

History1973 Decision to develop a satellite navigation system based on the systems TRANSIT, TIMATION und

621B of the U.S. Air Force and the U.S. Navy.1974 - 1979System tests 1977 First receiver tests are performed even before the first satellites are stationed in the orbit.

Transmitters are installed on the earthss surface called Pseudolites (Pseudo satellites) 1978 - 1985

A total of 11 Block I satellites are launched in this period.

1980 Launching of the first Block I satellite carrying sensors to detect atomic explosions. This satellite is meant to control the abidance of the agreement of 1963 between the USA and the Soviet Union to refrain from any nuclear tests on the earth, submarine or in space.

1979 Decision to expand the GPS system. Thereupon the resources are considerably shortened and the program is restructured. At first only 18 satellites should be operated.

1988 The number of satellites is again raised to 24, as the functionality is not satisfying with only 18 satellites.

1980- 1982

The financial situation of the project is critical, as the usefulness of the system is questioned again and again by the sponsors.

1983 When a civilian airplane of the Korean Airline (Flight 007) was shot down after it had gone lost over Soviet territory, it was decided to allow the civilian use of the GPS system.

1986 The accident of the space shuttle "Challenger" means a drawback for the GPS program, as the space shuttles were supposed to transport Block II GPS satellites to their orbit. Finally the operators of the program revert to the Delta rockets intended for the transportation in the first place.

http://www.kowoma.de

5

History

1989 The first Block II satellite was installed and activated. 1990 - 1991

Temporal deactivation of the selective availability (SA) during the Gulf war. In this period civil receivers should be used as not enough military receivers were available. On J uly 01, 1991 SA is activated again.

1993 The Initial Operational Capability (IOC) is announced. In the same year it is also definitely decided to authorize the worldwide civilian use free of charge.

1994 The last Block II satellite completes the satellite constellation. 1995 Full Operational Capability (FOC) is announced. 2000 Final deactivation of the selective availability and therefore improvement of the accuracy

for civilian users from about 100 m to 20 m. 2004 Launching of the 50st GPS satellite. 2005 Launch of the first IIR-M GPS-satellite. This new type supports the new military M-signal

and the second civil signal L2C. http://www.kowoma.de

Theory

Global Positioning System• GPS gives the user position, time and velocity, with better accuracy

and every second. The constellation consists of 24 ‘Navstar’ (Navigation Satellite Timing And Ranging) satellites, three of which are spares, ensuring that at least four are visible at any one time

• Each satellite broadcasts ephemerides - an algorithm that gives its spatial co-ordinates relative to the Earth’s centre - so its precise position in orbit is known.

• first signal places the receiver in the centre of a sphere a known distance from the first satellite. This distance is known as a ‘pseudorange’.

• . A second satellite’s signal provides two connected spheres, with a central intersection.

• A third signal puts the GPS receiver at one of two points, one of which can be discarded as not being on the Earth’s surface.

• three satellites should be able to pin-point the receiver’s location. • to measure distance, the receiver must know exactly when the signal

left the satellite.• the receiver and satellite generate a piece of code simultaneously,

called ‘pseudo-random’ code. 6

TeoriGlobal Positioning System

• GPS memberikan kedudukan pengguna, masa dan halaju, dengan ketepatan yang lebih baik dan setiap saat. Buruj terdiri daripada 24 'Navstar' (Navigation Satellite Timing And Ranging) satelit, tiga daripadanya adalah alat ganti, memastikan bahawa sekurang-kurangnya empat dapat dilihat pada bila-bila masa dan mana-mana satu.

• Setiap siaran satelit ephemerides - algoritma yang memberikan ruang yang bersama-ordinat relatif ke pusat Bumi - supaya kedudukan yang tepat dalam orbit dikenali.

• isyarat pertama meletakkan penerima di tengah-tengah sfera jarak dari satelit pertama. Jarak ini dikenali sebagai 'pseudorange'.

• Isyarat satelit kedua menyediakan dua sambungan sfera, dengan persimpangan pusat.

• Isyarat ketiga meletakkan penerima GPS di salah satu daripada dua mata, yang boleh dibuang sebagai tidak berada di permukaan Bumi.

• untuk mengukur jarak, penerima mesti tahu dengan tepat apabila isyarat meninggalkan satelit.

• penerima dan satelit menjana sekeping kod pada masa yang sama, yang dipanggil 'pseudo-rawak' kod. 7

The Satellites

• The satellites themselves are relatively large, using a multi-purpose military platform used for purposes other than global positioning, such as atomic flash detection.

• Twelve antennas point toward the Earth, and two solar arrays toward the Sun capable of generating 700 Watts, to drive the satellite’s navigation transmitters, its four atomic clocks, and its momentum wheels.

• The latest generation of satellites are designated ‘Block II’.

8

Satelit

• Satelit agak besar, ia menggunakan platform pelbagai guna yang digunakan oleh tentera untuk tujuan selain daripada kedudukan global, seperti pengesanan flash atom.

• Dua belas antena titik ke arah Bumi, dan dua tatasusun solar ke arah matahari yang mampu menjana 700 Watts, untuk memandu pemancar navigasi satelit, empat jam atom, dan roda momentum.

• Generasi terbaru satelit yang ditetapkan 'Block II'.

9

The Segments

• The operation of GPS is split into three segments.• The space segment is composed of the 24 Block II

Navstar satellites, that transmit precisely timed pulses of code and orbital data.

• The control segment helps keep track of the satellites with monitoring stations to find their exact orbit and any clock errors and hence correct the satellite’s own data if necessary.

• The user segment consists of all of the receivers located on the ground, or in aeroplanes, or in ships.

10

Segmen

• Operasi GPS dibahagikan kepada tiga segmen.• Segmen ruang yang terdiri daripada 24 Block II Navstar

satelit, yang menghantar denyutan tepat bagi menetapkan masa, kod dan data orbit.

• Segmen kawalan membantu menjejaki satelit dengan stesen pemantauan untuk mencari orbit yang tepat dan sebarang kesilapan jam dan seterusnya membetulkan data satelit itu sendiri jika perlu.

• Segmen pengguna terdiri daripada semua penerima yang terletak di atas tanah, atau kapal terbang, atau di kapal.

11

12

Three Parts

• Space segment

-segmen ruang

• Control segment

-segmen kawalan

• User segment

– segmen pengguna

13

Space Segment

• The Air force insures that at least 24 satellites are operational at all times.

• There are six orbital planes (with nominally four space vehicles (SVs) in each), equally spaced (60 degrees apart), and inclined at about fifty-five degrees with respect to the equatorial plane.– The satellite orbits are controlled so

that at least six should be available, unobstructed location, at all times.

– Each satellite circles the earth twice a day.• Each satellite broadcasts a unique signal that tells the

receiver its location and the exact time.

http://www.colorado.edu/geography/gcraft/notes/gps/gps_f.html

Segmen ruang

• Tentera Udara memastikan sekurang-kurangnya 24 satelit beroperasi pada setiap masa.

• Terdapat enam satah orbit (nominal empat kenderaan ruang (Svs) dalam setiap), pada jarak yang sama (60 darjah selain) dan cenderung pada kira-kira 55 darjah dengan satah khatulistiwa.– Orbit satelit yang dikawal bahawa sekurang-kurangnya

enam perlu disediakan, lokasi yang tidak terhalang, pada setiap masa.

– Setiap satelit mengelilingi bumi dua kali sehari.

• Setiap satelit siaran isyarat yang unik yang memberitahu penerima lokasi dan masa yang tepat.

14

15

Control Segment

•The Master Control facility is located at Schriever Air Force Base (formerly Falcon AFB) in Colorado.

•Originally Schriever AFB and four other stations monitored and controlled satellite positions.

•During August and September 2005, six more monitor stations of the NGA (National Geospatial-Intelligence Agency) were added to the grid.

•Now, every satellite can be seen from at least two monitor stations.•The Master Control station uploads ephemeris and clock data to the SVs. •The SVs then send subsets of the orbital ephemeris data to GPS receivers over radio signals.

A Synthetic Vision System (SVS) is a computer-mediated reality system for aerial vehicles, that uses 3D to provide pilots with clear and intuitive means of understanding their flying environment.

Segmen kawalan

• Kemudahan Kawalan Induk terletak di Schriever Air Force Base (dahulunya Falcon AFB) di Colorado.

• Originally Schriever AFB dan empat stesen-stesen lain yang dipantau dan dikawal kedudukan satelit.

• Semasa bulan Ogos dan September 2005, enam memantau stesen NGA (National Geospatial-Intelligence Agency) telah ditambah ke grid.

• Kini, satelit setiap boleh dilihat daripada sekurang-kurangnya dua stesen monitor.

• Master Kawalan stesen Gambar ephemeris dan data jam yang Svs.

• Svs kemudian menghantar subset data ephemeris orbit kepada penerima GPS melalui isyarat radio.

16

17

User Segment

• The primary use of GPS is navigation. • Navigation receivers are made for aircraft,

ships, ground vehicles, surveying, and for hand carrying by individuals.

• The accuracy of a receiver depends on the number of channels, compatibility with other navigational systems (WAAS, GLONAS, etc.) and design of the receiver (cost).

– Most civilian hand held units have an accuracy of 10 meters.

– Survey quality GPS units may be as good as one centimeter.

• The GPS User Segment consists of all GPS receivers.

– Surveying– Recreation– Navigation

• GPS receivers convert satellite signals into position, velocity, and time estimates.

• Four satellites are required to compute the four dimensions of X, Y, Z (position) and Time.

Segmen pengguna

• Penggunaan utama GPS navigation.• Penerima Navigation dibuat bagi pesawat udara, kapal, kenderaan

tanah, ukur, dan untuk tangan yang dibawa oleh individu.• Ketepatan penerima bergantung kepada bilangan saluran,

keserasian dengan sistem navigasi yang lain (WAAS, GLONAS, dll) dan reka bentuk penerima (kos).

-Yang tangan awam yang diadakan unit mempunyai ketepatan 10 meter.

-Survey kualiti GPS unit mungkin sebagai baik sebagai salah satu sentimeter.

• Segmen pengguna GPS terdiri daripada semua penerima GPS.-Ukur

-Rekreasi

-navigation

• Penerima GPS menukar isyarat satelit ke dalam kedudukan, halaju, dan anggaran masa.

• Empat satelit untuk mengira empat dimensi X, Y, Z (kedudukan) dan Masa.

18

19

User Segment--cont.

• Time and frequency dissemination, based on the precise clocks on board the SVs and controlled by the monitor stations, is another use for GPS.

• Astronomical observatories, telecommunications facilities, and laboratory standards can be set to precise time signals or controlled to accurate frequencies by special purpose GPS receivers.

• The GPS signals are available to everyone, and there is no limit to the number and types of applications that use them.

• Penyebaran masa dan kekerapan, berdasarkan jam tepat di atas kapal Svs dan dikawal oleh stesen monitor, satu lagi digunakan untuk GPS.

• Balai cerap astronomi, kemudahan telekomunikasi, dan standard makmal boleh ditetapkan untuk isyarat masa yang tepat atau dikawal kepada frekuensi tepat oleh penerima GPS bagi tujuan khas.

• Isyarat GPS tersedia untuk semua orang, dan tiada had untuk bilangan dan jenis aplikasi yang digunakan mereka.

Signals

• GPS satellites transmit on two L-Band frequencies: 1.57542 GHz (L1) and 1.22760 GHz (L2).

• The L1 signal is modulated by two codes - the P-code (precise) and the C/A-code (coarse acquisition).

• The L2 carrier contains only P-code, which is encrypted. However there are some civilian receivers which have the capability of using the L1 P-code without decoding it.

• The P-code is encrypted for use solely by authorised military users. The encryption is known as ‘Anti-Spoofing’.

• The C/A code is the standard freely available service for non-military users. Less accurate and unlike the P-code, easier to jam. It uses only one frequency and so can’t compensate for ionospheric delay as the P-code can. The C/A code is also degraded by a process known as ‘Selective Availability’.

20

Isyarat

• Satelit GPS menghantar isyarat kepada dua frekuensi :L-Band: 1,57542 GHz (L1) dan 1,22760 GHz (L2).

• Isyarat L1 termodulat oleh dua kod - P-kod (tepat) dan / C kod (pengambilalihan kasar).

• Syarikat penerbangan L2 mengandungi hanya P-kod yang disulitkan. Walau bagaimanapun, terdapat beberapa penerima awam yang mempunyai keupayaan menggunakan L1 P-code tanpa penyahkodan.

• P-kod disulitkan bagi kegunaan semata-mata oleh pengguna yang diberi kuasa oleh tentera. Penyulitan inidikenali sebagai 'Anti-menipu'.

• C / code perkhidmatan yang boleh diperolehi secara percuma untuk pengguna bukan ketenteraan. Kurang tepat dan tidak seperti P-code,ia lebih mudah untuk jem. Ia hanya menggunakan satu frekuensi.

21

Selective Availability

• Selective Availability (SA) describes the errors induced by the American Department of Defence (DoD) into the C/A code.

• It works in two ways: firstly by dithering the satellite clock. The second process is the process which introduces further inaccuracy by truncating the orbital information (the ephemerides), so the position of the satellites is not so accurately known.

• Selective availability is considered an important and useful mechanism, the DoD believe that GPS could be used against them. The periodical ‘GPS World’ reports that the threat is minor at present, but GPS could be used in conjunction with other technology to pose more danger in the future.

• For instance unstable developing countries could use the GPS system without SA to accurately aim cruise missiles, where an error of 100m could mean the difference between hitting a military target or missing it (improvements of 20-25% are expected). Absurdly due to this demand for military receivers, troops are now being issued with civilian receivers which would mean SA would have to be removed should the US go to war .

22

Selective availability

• Selecvtive Availability(SA) menerangkan kesilapan yang dikenalpasti oleh Jabatan Pertahanan Amerika (DOD) ke dalam C / A kod.

•  Ia bertindak dalam dua cara: pertama dengan penggetaran jam satelit. Proses kedua adalah proses yang memperkenalkan ketidaktepatan lanjut dengan truncating maklumat orbit (ephemerides), jadi kedudukan satelit tidak begitu tepat dikenali.

• Ketersediaan terpilih dianggap sebagai mekanisme yang penting dan berguna, DOD percaya bahawa GPS boleh digunakan terhadap mereka. 'Dunia GPS' melaporkan bahawa ancaman kecil berkala pada masa ini, tetapi GPS boleh digunakan bersama-sama dengan teknologi lain untuk menimbulkan bahaya yang lebih pada masa akan datang.

• Sebagai contoh negara-negara membangun boleh menggunakan sistem GPS tanpa SA dengan tepat bertujuan melepaskan peluru berpandu, di mana ralat-100m mungkin perbezaan antara sasaran ketenteraan atau hilang (peningkatan sebanyak 20-25% dijangka).

23

The Transit System

• Transit was the first satellite navigation system, implemented in the early sixties. It has the same military origins as GPS, but works on the Doppler principle. By measuring the shifted frequencies from the satellites, it is possible to derive its range, and hence from a number of other orbital positions, the observer’s position.

• The Transit system consists of six satellites with two transmitting frequencies of 150 MHz and 400 MHz. The accuracy is given as 250m at the 95% level, and each fix is given roughly every 90 minutes.

• Transit was switched off at the end of 1996.

24

Sistem Transit

• Transit adalah sistem navigasi satelit yang pertama, yang dilaksanakan pada awal tahun enam puluhan. Ia mempunyai asal-usul yang sama sebagai GPS, tetapi kerja-kerja pada prinsip Doppler. Dengan mengukur frekuensi yang beralih dari satelit, ia mungkin untuk memperolehi rangkaian, dan dengan itu daripada beberapa kedudukan orbit yang lain dan kedudukan pemerhati.

• Sistem Transit terdiri daripada enam satelit dengan dua frekuensi pemancar 150 MHz dan 400 MHz. Ketepatan diberikan sebagai 250m di peringkat 95%, dan menetapkan setiap ketepatan diberikan kira-kira setiap 90 minit.

• Transit telah dimatikan pada akhir tahun 1996.

25

Conclusion

• The technology of the Global Positioning System is allowing for huge changes in society. The applications using GPS are constantly growing. The cost of the receivers is dropping while at the same time the accuracy of the system is improving. This affects everyone with things such as faster Internet speed and safer plane landings.

• Even though the system was originally developed for military purposes, civil sales now exceed military sales (See Figure 1 below).

26

Kesimpulan

• Teknologi Global Positioning System membenarkan perubahan besar dalam masyarakat. Aplikasi yang menggunakan GPS sentiasa berkembang. Ini memberi kesan kepada semua orang dengan perkara-perkara seperti kelajuan internet yang lebih cepat dan pendaratan kapal terbang yang lebih selamat.

• Walaupun sistem yang pada asalnya dibangunkan untuk tujuan ketenteraan, jualan awam kini melebihi jualan tentera (Lihat Rajah 1 di bawah).

27

Graph shown the use of gps by public

28

GPS Update

• On May 1, 2000 President Clinton announced that the government will no longer scramble signals from the GPS satellites. This means that civilians will be able to enjoy the high accuracy that the military has had for years. The DGPS techniques and the equipment needed to use them will no longer be necessary to get the same effects on accuracy. The affects on society will be:

-more reliable and accurate measurements-less costly to corporations - since the error removing

equipment will no longer be needed-more affordable and accessible to consumers-greater incentive for the development of new uses

• The accuracy should increase ten-fold, from 100 meter to 10 meter accuracy. The $8 billion dollar a year GPS industry should also see a much larger than expected increase in sales.

 

29

GPS Update

• Pada 1 Mei, 2000 Presiden Clinton mengumumkan bahawa kerajaan tidak lagi akan berebut isyarat dari satelit GPS. Ini bermakna bahawa orang awam akan dapat menikmati isyarat ketepatan yang tinggi seperti yang telah digunakan oleh tentera selama bertahun-tahun. Teknik DGPS dan peralatan yang diperlukan untuk digunakan oleh mereka tidak lagi perlu bagi mendapatkan kesan yang sama terhadap ketepatan.

• Kesan kepada masyarakat ialah:– ukuran lebih boleh dipercayai dan tepat– kurang mahal kepada syarikat-syarikat-sejak kesilapan

mengeluarkan peralatan tidak lagi akan diperlukan– lebih mudah dan murah kepada pengguna– Insentif yang lebih besar untuk pembangunan kegunaan baruKetepatan meningkat sepuluh kali ganda, daripada 100 meter kepada

10 meterketepatan. Dolar $ 8 bilion tahun industri GPS juga harus melihat

peningkatanyang jauh lebih besar daripada yang dijangkakan dalam jualan.

30

References

• http://en.wikipedia.org/wiki/Global_Positioning_System• http://www.ion.le.ac.uk/kallisto/dgps_project.html• http://www8.garmin.com/aboutGPS/• http://www.flygps.com/gps/sld009.html

31

THANKYOU

32