INDIAN REGIONAL NAVIGATION SATELLITE SYSTEM

Transcription

1 INDIAN REGIONAL NAVIGATION SATELLITE SYSTEM R. Shriwas 1, R. Bele 2, R. kalaskar 3, P. Jaiwsal 4 Prof. Ravi S. Shriwas- ravi.shriwas@gmail.com Ms. Rupali D.Bele - rupalibele02@gmail.com Ms.Rhutuja R. Kalaskar- rhutujakalaskar14@gmail.com Ms. Payal Jaiswal- jaiswalsonal@gmail.com Department of Electronics and Telecommunication Engineering, Jawaharlal Darda Institute of Engineering and Technology, Yavatmal, India ABSTRACT The Indian Regional Navigation Satellite System (IRNSS) is an emerging satellite based navigation system offering an independent positioning and timing service over India and neighbouring regions. Based on satellite laser ranging data collected by selected stations of the International Laser Ranging Service (ILRS) precise orbits have been determined for the first pair of inclined geosynchronous satellites (IRNSS-1A/B). These orbits are used to assess the quality of the IRNSS navigation messages. A Signal in-space Range Error (SISRE) at the five meter level is confirmed which is consistent with the accuracy assessment given in the message itself. Even though the current satellite constellation does not yet support stand alone navigation, the results offer a first indication of the navigation equality that can be expected by future users in the area. The Indian Regional Navigational Satellite System (IRNSS) is an autonomous regional satellite navigation system being developed by the Indian Space Research Organization (ISRO) which would be under complete control of the Indian government. The requirement of such a navigation system is driven by the fact that access to Global Navigation Satellite Systems, GPS is not guaranteed in hostile situations. The IRNSS would provide two services with the Standard Positioning Service open for civilian use and the Restricted Service. Keywords: IRNSS, GPS, ISRO,GNSS etc INTRODUCTION TO IRNSS ISRO developed a satellite based navigation system called Indian Regional Navigation Satellite System (IRNSS) with a constellation of 7 satellites and complementary round infrastructure. Two spare satellites are also planned. The IRNSS system was planned to be made operational by end of Government has approved the IRNSS project at a total cost of Rs crores in May 2006 for both space and ground infrastructure. The IRNSS is expected to provide positional accuracies similar to the Global Positioning System (10 meters over Indian landmass and 20 meters over the Indian Ocean) in a region centred around the country with a coverage extending up to 1,500 km from India between longitude 40 E to 140 E and between latitude ± 40. IRNSS was featured with highly accurate position, velocity and time information in real time for authorized users on a variety of vehicles. This system provides Data with good accuracy for a single frequency user with the help of Ionospheric corrections and also provide all environmental operation on a 24 hour basis. Polar Satellite Launch Vehicle in its twenty fourth flight (PSLV-C22) have launched India s first dedicated navigational satellite system IRNSS-1A. Each IRNSS satellite weights about 1,380 kg and

2 their solar panels generate 1,400 Watt of power. The satellites will be configured with an optimized I-1K bus (compatible for launch onboard PSLV) with a power handling capability of around 1600W. The IRNSS mainly consists of three segments: space segment, ground segment and user segment. The ground segment of the IRNSS constellation would consist of a Master Control Centre (MCC) (stationed at Karnataka) and ground stations to track and control the satellites. The MCC would predict the position of all satellites, integrity, make necessary ionospheric and clock corrections and run the navigation software. The navigation software has been indigenously developed at ISRO Satellite Centre. The software modules interface with various subsystems of the ground segment and generate navigation parameters required for broadcast from the spacecraft. The satellite system will provide two basic services Standard Positioning Service (SPS) for civil users and Restricted Service (RS) with encryption for special authorised users like the armed forces. The navigation signals would be transmitted in the S-band frequency (2-4 GHz) and the system expected to provide an absolute position accuracy of about 10 metres over India as well as the region extending 1,500 km around India. The system will provide accurate Position, Navigation and Time (PNT) services on various platforms with all the time availability under all environmental conditions. As of now, the IRNSS is a regional system with s even satellites, which would be further expanded into eleven satellites in the coming years, civil aviation is one of the sectors that will benefit from the IRNSS and satellite based augmentation system. We currently have 456 airfields and 85 operational airports in the country. ISRO has also developed a GPS supported geo-augmented navigation system (GAGAN) to assist the navigation of civilian air traffic over Indian airspace. Once the IRNSS and GAGAN are fully functional, They will help us with precise navigation, provide data on mountainous, oceanic areas and enhance security tremendously. The vast spectrum of services that would be provided by the network will be significant to the growth of the nation in the field of science and space technology which would proper our economic growth in the years to come. The objective of the IRNSS is to implement an independent and indigenous regional space born navigation system for national applications. The IRNSS design requirements call for a position accuracy of < 20 m throughout India and within the region of coverage extending about 1500 km beyond. The system is expected to provide accurate real-time position, velocity and time observables for users on a variety of platforms with 24 hour x 7 day service availability under all weather conditions. The IRNSS was being developed parallel to the GAGAN (GPS Aided GEO Augmented Satellite Navigation) program, the ISRO SBAS (Satellite Based Augmentation System) version of an overlay system for GNSS signal corrections. The IRNSS system consists of a constellation IRNSS was featured with highly accurate position, velocity and time information in real time for authorized users on a variety of vehicles. This system provides Data with good accuracy for a single frequency user with the help of Ionospheric corrections and also provides all environmental operation on a 24 hour basis. Polar Satellite Launch Vehicle in its twenty fourth flight (PSLV-C22) have launched India s first dedicated navigational satellite system IRNSS-1A. Each IRNSS satellite weights about 1,380 kg and their solar panels generate 1,400 Watt of power. The satellites will be configured with an optimized I-1K bus (compatible for launch onboard PSLV) with a power handling capability of around 1600W. The IRNSS mainly consists of three segments: space segment, ground segment and user segment. The ground segment of the IRNSS constellation would consist of a Master Control Centre (MCC) (stationed at Karnataka) and ground stations to track and control the satellites. The MCC would predict the position of all satellites, integrity, make necessary ionospheric and clock corrections and run the navigation software. The navigation software has been indigenously developed at ISRO Satellite Centre. The software modules interface with various subsystems of the ground segment and generate navigation parameters required for broadcast from the spacecraft. The satellite system will provide two basic services Standard Positioning Service (SPS) for civil users and Restricted Service (RS) with encryption for special authorised users like the armed forces. The navigation signals would be transmitted in the S-band frequency (2-4 GHz) and the system expected to provide an absolute position accuracy of about 10 metres over India as well as the region extending of seven satellites and a supporting ground segment. Three of the satellites in the constellation will be placed in a geostationary orbit and the remaining four in a geosynchronous inclined orbit of 29º relative to the equatorial plane. Such an arrangement would mean all seven satellites would have continuous radio visibility with Indian control station. 2. ARCHITECTURE OF IRNSS The IRNSS will consist of three segments: space, ground and user. The space segment consists of a constellation of seven satellites: three (Geostationary Orbit) GEOs located at 34 E, 83 E and E and four (Geosynchronous Orbit) GSOs at an inclination angle of 29 placed two each at with equator crossing at 55 and

3 111 East. IRNSS ground segment consist ground stations for generation and transmission of navigation parameters, satellite control, satellite ranging and monitoring. A total of 20 stations are planned, most of them located at airports along with GAGAN ground elements. IRNSS will have two types of signals in L5 ( MHz) & S ( MHz) band. Both L5 and S-band consists of two downlinks. IRNSS provides two basic services such as Standard Positioning Service (SPS) for common civilian users and Restricted Service (RS) for special authorized users. The system can be augmented with local area augmentation for higher accuracy. Table1: IRNSS SERVICES Service Type Signals Frequency Band Standard Positioning Service Mcps L5( Mhz) S( Mhz) Precise Positioning Service Mcps L5 S Restricted Services for Special Users Mcps L5 Fig1. IRNSS CONSTELLATION

4 2.1 Space Segment The space segment consists of seven satellites with three satellites in GSO orbit and four satellites in GSO orbit. The 3 GSOs is located at 32.5º E, 83º E and 131.5º E and the 4 GSOs have their equatorial longitude crossings at 55º E and º E (two in each plane) as shown in Figure1. IRNSS satellites have two types of payloads, navigation and ranging payload. The navigation payload will transmit the ranging codes being generated onboard along with the navigation data uplink from the ground stations. 2.2 Ground segment The ground segment is responsible for navigation data generation, spacecraft control and maintenance of IRNSS constellation. It comprises of ISRO navigation centre (INC) responsible for estimation of navigation parameters for IRNSS satellites, IRNSS Range and Integrity Monitoring Stations (IRIMS) for one way ranging, IRNSS CDMA Ranging Station for two way ranging, Laser ranging stations, IRNSS Spacecraft Control Facility Centre for health monitoring, analysis and control of IRNSS satellites, IRNSS Network Timing centre (IRNWT) for precise time generation for IRNSS system and Data communication network. 2.3 User segment The User segment mainly consists of: Single frequency IRNSS receiver capable of receiving signals at L5 or S band frequency, dual frequency IRNSS receiver capable of receiving both L5 and S band frequencies and receiver compatible to IRNSS and other GNSS signals. Each IRNSS satellite provides SPS and RS signals in L5 and S band. 3. ANALYSIS OF IRNSS 3.1 CONSTRUCTION OF A SATELLITE: Each IRNSS satellite will weigh about 1,380 kg and their solar panels generate 1,400 Watt of power. The satellites will be configured with an optimized I-1K bus (compatible for launch onboard PSLV) with a power handling capability of around 1600W. The satellite is designed for a nominal life of 7 years. Its payload will consist of electronic equipment to generate navigation signals and extremely accurate on-board atomic clocks. The navigation signals in S-band (2-4 GHz) are fed to a high performance phased array antenna for the required coverage. There is a ranging payload consisting of a C-band transponder that facilitates accurate determination of the range of the satellite. IRNSS-1A also carries corner-cube retro-reflectors for laser ranging. Fig2. IRNSS Satellite Components

5 3.2 SATELLITES IRNSS-1A IRNSS-1A was the first navigational satellite in the Indian Regional Navigation Satellite System series of satellites to be placed in geosynchronous orbit. It was built at ISRO Satellite Centre, Bangalore, costing Rupees 125 crore (US$19 million). It has a lift-off mass of 1380 kg, and carries a navigation payload and a C- band ranging transponder, which operates in L5 band ( MHz) and S band ( MHz). An optimized I-1K bus structure with a power handling capability of around 1600 watts is used and designed for a ten-year mission. The satellite was launched on-board PSLV-C22 on 1 July 2013 from the Satish Dhawan Space Centre at Sriharikota IRNSS-1B IRNSS-1B is the second out of seven in the Indian Regional Navigation Satellite System. It was very precisely and successfully placed in its orbit through PSLV-C24 rocket on 4 April IRNSS-1C IRNSS-1C is the third out of seven in the Indian Regional Navigation Satellite System series of satellites. The satellite was successfully launched using India's PSLV-C26 from the Satish Dhawan Space Centre at Sriharikota on 16 October 2014 at 1:32 am. IRNSS-1D IRNSS-1D is the fourth out of seven in the Indian Regional Navigation Satellite System series of satellites system. It was successfully launched using India's PSLV-C27 on 28 March 2015 at 5:19 pm. IRNSS-1E IRNSS-1E is the fifth out of seven in the Indian Regional Navigation Satellite System series of satellites system. It was successfully launched on 20 January 2016 using India's PSLV-C31 at 9:31 am. IRNSS-1F IRNSS-1F is the sixth out of seven in the Indian Regional Navigation Satellite System series of satellites system. It was successfully launched on 10 March 2016 using India's PSLV-C32 at 4:01 pm. IRNSS-1G IRNSS-1G is the seventh out of seven in the Indian Regional Navigation Satellite System series of satellites system. It is targeted for launch on April 2016 using India's PSLV. 3.3 IRNSS CONSTELLETION PROGRESS The full constellation of 7 satellites is planned to be realized by Six satellites IRNSS-1A, IRNSS-1B, IRNSS-1C, IRNSS-1D, INRSS-1E, INRSS-1F have been already launched. IRNSS-1G is scheduled to be launched in April IRNSS-1G was earlier scheduled to be launched during session , but would now be launched in By the middle of 2016, the IRNSS would be able to provide of seven satellites that will comprise IRNSS is a major step towards boosting India s navigation satellite program. The system will start operating once four satellites are up and it will be fully operational by Indian Regional Navigation Satellite System (IRNSS) and its sixth navigation satellite system in whole world.

6 Fig3. Signal receive from IRNSS Fig4. IRNSS space segment comprising of 7satellite 4. HISTORY OF NAVIGATION SATELLITE SYSTEM The combinations of radio frequency signals and satellite which enhance the process of navigation called navigation satellite system.global Satellite Navigation Systems (GNSS) use radio signals transmitted by satellites to enable mobile receivers to determine their exact location. Each GNSS satellite broadcasts a signal that contains the position of the satellite and the precise time the signal was transmitted. The position of the satellite is transmitted in a data message that is superimposed on a spreading code that serves as a timing reference. The satellite uses an atomic clock to maintain synchronization of all the satellites in the constellation. The receiver compares the time of broadcast encoded in the transmission with the time of reception measured by an internal clock, thereby measuring the time-of-flight to the satellite has to calculate the point where pseudoranges from a set of satellites intersect (pseudo-range is a distance measurement based on the correlation of a satellite transmitted code and To estimate how far away a satellite is the receiver determines the sizes of several spheres centred at each satellite. If three satellites are available with known positions, then three spheres are known, whose intersection is two points, one of which is the receiver s location: in theory, the problem is reduced to computing this intersection. However, there is a major problem with the above analysis: the satellites transmissions are precisely timed within 10-7 sec by onboard atomic clocks. In respect of this, the clock in the typical low-cost receiver on Earth has a relatively poor accuracy, so if we solve the three equations with slightly inaccurate timing, the calculated position could be wrong by several kilometres. To solve this problem, the price to pay is one extra satellite. That is why at least four navigation satellites are required to solve the all three dimensions of location latitude, longitude, and altitude and time. The antenna at a user terminal should be able to provide good reception of multiple satellites signals coming from different directions at the upper hemisphere. 5. COMPARISON WITH OTHER NAVIGATOINAL SATELLITE SYSTEM 5.1 GPS The best known satellite navigation system is the Global Positioning System (GPS) developed by the US military and became fully operational on 17 July This system consists of 24 to 28 satellites that orbit in six different planes. The exact number of satellites varies as satellites are replenished when older ones are retired. They orbit at an altitude of approximately 20,000 km with an inclination of 55 degrees.

7 Fig5. GPS Satellite Constellation GPS has been recognized as the future of navigation for different applications: the civil community is one of the main benefactors of its flexibility and worldwide applicability. 5.2 GLONASS The Russian counterpart to GPS is called GLONASS. Like GPS, fully deployed GLONASS constellation is composed of 24 satellites in three orbital planes whose ascending nodes are 120 degrees apart. Each GLONASS satellite operates in near-circular km orbits at an inclination angle of 64.8 degrees and completes an orbit in approximately 11 hours 15 minutes. The spacing of satellites in orbits is arranged so that a minimum of 5 satellites from the nominal constellation of 24 satellites are in view to user s world-wide with adequate geometry. 5.3 Galileo Union and European Space Agency have agreed (March 2002) to introduce their own alternative to GPS called Galileo. The required satellites will be launched between 2006 and 2012 and the system is expected to be working, under civilian control, from 2012 when the full operational mode is planned to be achieved. Galileo is expected to be compatible to the next-generation GPS system that will be operational by The receivers will be able to combine the signals from 30 Galileo and 28 GPS satellites. 5.4 Beidou The china s Beidou navigation system is global system; currently with local service coverage utilising satellites is geostationary orbit, future extension to the global coverage over china and surrounding area. The full constellation will consist of 5 satellites in geostationary orbit at an altitude of 36,000 Km. 3 inclined at geosynchronous orbit at an altitude of 36,000 Km and remaining 27 satellites are inclined at an altitude of 21,000 Km in 3 orbital planes.by October 2012, 16 Satellites were launched. The system not yet operational. 5.5 QZSS Japan s Quasi-Zenith Satellite System (QZSS) covering the Japanese Flight Information region. 3 satellites in elliptical orbits at an altitude 40,000 Km by 30,000 Km, each in different orbital plane, intended to be use along with GPS satellites improve location services over Japan. First satellite launched in The global and regional Satellite Navigation Systems are summarised in table2: Sr.NO System Start/End of operability Carrier Frequencies Coverage 1. GPS US GHz(L1) GHz(L2) 1.176GHz(L5) 2 GLONASS Russia 1995(25sat) 1998(13sat) 2010(24sat) 1.6GHz 1.2Hz GLOBAL GLOBAL

8 3 Galileo Europe 2008/ GH(E5a) GLOBAL 1.207GHz(E5b) 1.278GHz(E6) 4 Beidou China GHz ASIA 6. FUTURE SCOPE The successful launch by ISRO of the second of the string of seven satellites that will comprise the Indian Regional Navigation Satellite System (IRNSS) is a major step towards boosting India s navigation satellite programme. The system will start operating once four satellites are up and it will be fully operational by The fourth satellite IRNSS-1D was launched recently in March Three more satellites will be launched by mid 2015 after which India would have seven constellations of seven satellites carrying out important services. Indeed, the satellite launches would revolutionise the entire navigation business. System offers a reliable alternative for military applications, which alone makes it worth building. However, about 95 percent of IRNSS usage is likely to be in the in the civilian domain and there s plenty of scope for commercial payoffs there. The system will be used for terrestrial, aerial and marine navigation, disaster management, vehicle tracking and fleet management, integration with mobile phones, mapping and geodetic data capture. The navigational system developed by India is designed to offer accurate position information service to users within the nation and upto 1,500 km from its boundary line. The system is similar to the (GPS) global positioning system of the US, GlONASS of Russia, Galileo of Europe, China s Beidou or the Japanese Quasi Zenith Satellite (QZSS) System. In July 2013, PSLV-C22 had launched IRNSS-1A, which is operating satisfactorily from its designated geostationary orbital position. The launch of the second IRNSS that also marked the 25th success in a row for the PSLV had boosted the image of the launching vehicle. 7. ADVANTAGES 1. The IRNSS system provides highly accurate position, velocity and time information in real time for authorized users on a variety of vehicles. 2. It provides Data with good accuracy for a single frequency user with the help of Ionospheric corrections. 3. All weather operation on a 24 hour basis. 4. Terrestrial, aerial & marine Navigation. 5. The IRNSS L5 and S1 will transmit signals for civilian use and will adopt the BPSK modulation scheme. 6. Location based services, fleet management: 7. Security: as vehicle tracking, tracking of animals to avoid clashes like elephants, Protection from criminal and hackers. 8. Military uses: satellite can be used for precision guiding of missiles, bombs and aircraft. 8. IRNSS APPLICATIONS 1. IRNSS provides fairly good accuracy and the whole constellation is seen all the time. There are plans to send integrity and ionospheric correction messages to the user. 2. A variety of applications taking the benefit of above will be catered by IRNSS. 3. In view of the independent nature of the constellation it is planned to cater to specialized users. 4. Surveying and town/construction planning: precision pinpoint of geographical location can be used to set markers. 5. Disaster management: rescue operation can be aided by the IRNSS. Also techniques are available to detect fault movement and land deformation. 6. Agriculture: Precision agriculture taken into account the soil type, weather and crop and helps in increasing the output.

9 7. Vehicle tracking and fleet management. 9. CONCLUSION The success of the Independent IRNSS programme would make India self sufficient and in full control of its space based assets. The Indian Regional Navigation Satellite System envisages establishment of constellation made up of combination of geostationary Earth orbit (GEO) and geosynchronous orbit (GSO) spacecraft over the Indian Regional. This seminar proposed first, an optimization with respect to the satellite signal payloads distributed across GAGAN and IRNSS was deduced. Based on this, the third frequency of operation for IRNSS was designed. Finally, GAGAN signals as part of IRNSS were proposed. The proposal was experimentally analysed and verified. This seminar has presented a scheme to optimize the satellite payloads and thereby achieve a drastic reduction in the satellite hardware and associated ground station networks. ACKNOWLEDGEMENT We take this opportunity to express our gratitude and deep regards to our Prof. R.S.Shriwas for his exemplary help for the topic selection, valuable guidance, monitoring and constant encouragement throughout course of this paper. We have taken this opportunity to express a deep sense of gratitude to our Head of Department Dr. S. M. Gulhane for his cordial support, valuable information, guidance and all facilities provided in department for our convenience and completing the project through various stages. We are highly indebted to Principal of our college Dr. A.W.Kolhatkar for all facilities provided in college and to help to innovate our thoughts and ideas under the conduction of paper presentation in college. Lastly thanks to almighty and each other for constant encouragement without which this assignment would not be possible. REFERENCES [1] Ganeshan A. S., Rathnakara S. C., Gupta R., Ja in A.K. (2005) Indian Regional Navigation Satellite System (IRNSS) Concept, ISRO Satellite Centre Journal of Spacecraft Technology, 15(2): [2] Ganeshan A.S. (2012) Overview of GNSS and Indian Navigation Program, GNSS User Meeting, 23 Feb. 2012, ISRO Satellite Centre, Bangalore. [3] Saikiran B, Vikram V (2013) -IRNSS Architecture and Applications, KIET Institute of Comm. & Electronics. [4]. GAGAN Update Dr. Arjin Singh, Additional GM, Directorate of Global Navigation System, Airport Authority of India. [3]. [5]. "India's first dedicated navigation satellite placed in orbit", NDTV, 2 July [6]. "ISRO opens navigation centre for satellite system", Zeenews.com, [7]. "India Making Strides in Satellite Technology", Defense News, 26 July 2012 [8]. "India's first ever dedicated navigation satellite launched", DNA India. 2 July [9]. K.N. SuryanarayanaRao and S. Pal. The Indian SBAS System GAGAN, Abstract from the India-United States Conference on Space Science, Applications, and Commerce, June 2004.