Indian GNSS Paradigm

Dr. S. PAL [FIEEE, FNAE, FNASc, Dist. Fellow IETE, IET(UK), MIAA(Paris)] Vice Chancellor Defence Instute of Advanced Technology, (Deemed University), Girinagar, Pune – 411025 (Former S. Dhawan Professor and Senior Advisor SATNAV-ISRO)

A.S.GANESHAN

Program Director - SATNAV SCPNT-12-13 Nov.2015 ISAC/ISRO, Bangalore STANFORD PALOALTO 1

Indian GNSS Paradigm

Ø Satellite Posioning System (SPS) started in 1996. First SPS was used On Board IRS-P4. In-house orbit determinaon soware SANGAM was developed. Ø Satellite Based Augmentaon System (SBAS) studies were undertaken along with AAI in 2001. GAGAN project was formed in 2003. Technology Demonstraon System (TDS) was over in 2007 and Final Operaonal Phase (FOP) from year 2009 to 2013. Ø GAGAN cerfied for APV1.0/1.5 in April, 2015. Ø Indian Regional Navigaon Satellite System (IRNSS) studies were started in 2003. Project formulaon was completed in 2006. First IRNSS satellite was launched on 1st July, 2013. Constellaon of seven satellites is slated to be completed by 2016. Ø Collaborave studies and efforts have been connuously undertaken with GPS, GLONASS, EGNOSS/GALILEO and JAXA. Ø Ionospheric & Tropospheric – Studies and modeling

India may become a great user of GNSS for GIS, mobile, survey, mining, fishing industry, aviaon, road, rail transport etc. 2

Major Specificaons of SPS Description Specification Remarks

Type of System GPS Receiver, L1, C/A (6/8/10/12 In Future, this could change Channel SPS) in a Multi-GNSS L1 C/A, L2C & GAGAN (21 environment Channel SPS)

No of Channels 6/8/10/12/21 More Channels need More On-board Resources

Time To First Fix 480/100/85/80 (Sec) Faster is Better

Velocity ± 10 km LEO Satellites typically (Doppler range of about orbit at 28,000 km/h speed 100KHz at L1 frequency)

Acceleration 5g High during launch/re- entry. On-Orbit much lesser.

On-board storage 2 Orbits Data Down linked at 16 kbps through a Ground Station

S/C Interface MIL-1553B or Serial Mission Requirements3 GNSS-based Satellite Posioning System GNSS Receiver is used to compute precise orbit of LEO satellites. The major challenges are § Very high velocity § Wider visibility angle § Frequent memory/data corrupon § Auto-recovery § 24/7 operaon for many years Specialized acquision tracking algorithms, dual- redundant dissimilar hardware, screening and special processes are used to meet the above challenges. GNSS-based SPS are successfully flown since 1999 in many missions including IRS P4, TES, IRS P6, IRS P5, CARTOSAT, SRE, Ocean Sat etc. Further GNSS Receiver is used in the PSLV launch vehicles starng from C8.

4 SPS: Performance Enhancements (1999-2016) (Posion Accuracy in meters & No. of Channels)

120 25

100 100 21 20

80 15 Accuracy 60 12 Channels 50 10 10 40 8 6 5 20 15 8 3 0 0 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 2018

• SPS provides a mechanism of precise time transfer for On Board Timer (OBT) and Precise to Payloads (Science Missions). Transfer of • Plot showing achieved time transfer accuracy of better Time than 1µsec for ASTROSAT mission. 5 Navigaon- Air, Sea and Land Posioning Applicaons Survey Image Correcon GIS Timing Surveillance/Fleet Monitoring 6 SBAS System Universally

15.3 dBi 17.1 dBi 16.8 dBi 15 dBi 15 dBi

7 System Configuraon of GAGAN

8 Common coverage of GAGAN GEO satellites GAGAN payload is a hosted payload already operaonal through GSAT-8 (55oE), GSAT10 (83oE) operang in L1 (1575.42 MHz) and L5 (1176.45 MHz) bands GSAT-15 (93.5oE) :To be launched GSAT-1 GSAT-8 GSAT-10 5 Launched on Launched on Slated for launch 21st May,2011 29th Sept,2012 by Nov,2015

broadcasng broadcasng Will broadcast GAGAN signal with GAGAN signal with GAGAN signal with PRN128 PRN127 PRN 139 Antennas:0.7m & Antennas:0.6 m C- 0.9m parabolic for band and 0.8m X 0.7m prime focal C band, sixteen Rx & 0.8m X 0.8m 0.8m L-band element helical helical antenna helix array Tx antenna for L band 9 GAGAN Ground Segment

15 Indian Reference Staons (INRES) at Ahmedabad, Bengaluru, Bhubaneswar, Kolkata, Delhi, Dibrugarh, Gaya, Goa, Guwaha, Jaisalmer, Jammu, Nagpur, Porbandar, Port Blair, Trivandrum. 2 Indian Master Control Centers (INMCC) at Bengaluru. 3 Indian Land Uplink Staons (INLUS) at Bengaluru and Delhi. 4 Data Communicaon Networks (2 OFC + 2 VSAT)

10 GAGAN TDS Posion Plots for 24 hrs

11 The objective of GAGAN-FOP was to realize a certified and operational SBAS for all phases flight path over the Indian Flight Information Region (FIR) to provide air navigation services. Certified Performance:

Navigation Approach with Performance Vertical (RNP) 0.1 en Guidance route (APV)-1/1.5 navigation precision within Indian approach over FIR Indian FIR.

12 13 GAGAN Cerficaons GAGAN has been cerfied by Directorate General of Civil Aviaon (DGCA) for the provision of RNP 0.1 and APV 1.0 services.

• RNP 0.1 Service Cerficaon: 30-Dec-2013 Commissioning: 14-Feb-2014 • APV 1.0 Service Cerficaon: 21-Apr-2015 Commissioning: 19-May-2015

3 GEO’s GSAT-8, GAST-10 and GSAT-15 carry GAGAN Payload. 14 Indian Regional Navigaonal Satellite System (IRNSS) Constellaon

IRNSS-1A

IRNSS-1B IRNSS-1C IRNSS-1D • IRNSS is being realized by the Indian Space Research Organizaon (ISRO). • The main objecve is to provide Reliable Posion, Navigaon and Timing services. • Provides the user with a targeted posion accuracy of beer than 20 m over India and the region extending to about 1500 km around India. • Provides Standard Posioning Service (SPS) and an Encrypted Restricted

Service (RS). 16 IRNSS Architecture

IRNSS-1B GEO at 83° E GEO at 131.5° E IRNSS-1C GEO at 32.5° E GSO at 55° E GSO at 111.75° E IRNSS-1A IRNSS-1D

17 IRNSS Architecture Space segment •Seven satellites configuraon, 3 SVs in Geo-Staonary orbit ( 32.5°, 83° and 131.5° East), 4 SVs are in GEO Synchronous orbit placed at inclinaon of 29° (two each at 55° and 111.75° East Longitude crossings ) •The satellites are specially configured for Navigaon. •IRNSS satellites are to be launched by the Indian launcher PSLV. •Payloads transmit on L5 (1164.45 MHz-1188.45 MHz) and S (2483.5 MHz-2500 MHz) bands. Ground Segment • 4 IRNSS CDMA Ranging Staon (IRCDR) • Mulple LASER Tracking Staons • 15 IRNSS Range & Integrity Monitoring Staons (IRIMS) • IRNSS Spacecra Control Facility (IRSCF) • IRNSS Navigaon Centre (INC) • IRNSS Network Time Centre (IRNWT) User Segment • Includes a dual-frequency (L5 and S band) IRNSS receiver, a GNSS receiver compable with IRNSS, GPS, GLONASS and Galileo. 18 IRNSS Satellites Specificaons IRNSS 1A IRNSS 1B IRNSS 1C IRNSS 1D Launch Date 1st July, 2013 4th April, 2014 16th Oct, 2014 28th March, 2015 Launch Vehicle PSLV-C22 PSLV-C24 PSLV-C26 PSLV-C27

Orbit GSO at 55° E with GSO at 55° E with GEO at 83° E GSO at 111.75° E 29° inclinaon 29° inclinaon with 30.5° inclinaon

Li-OFF Mass (Kg) 1425 1432 1425.4 1425 Dry Mass (Kg) 614 614 600.1 603 Power Generaon 1660 1660 1660 1660 Capability (W)

Physical 1.58 m X 1.50 m X 1.58 m X 1.50 m 1.58 m X 1.50 1.58 m X 1.50 m X Dimensions 1.50 m X 1.50 m m X 1.50 m 1.50 m

Mission Life 10 years 10 years 10 years 10 years

All the seven satellites of IRNSS are expected to be in orbit by 2016. 19 IRNSS-1D Undergoing Solar Panel Deployment Test PSLV C-24 Payload Fairing enclosing the IRNSS-1B

20 IRNSS-1C spacecra undergoing EMI-EMC Tests IRNSS-1C spacecra undergoing Vibraon Test IRNSS Coverage 17 dBi Primary Service Region Polygon for IRNSS-1C: India mainland and surrounding 1500 km Extended service Region Polygon: Long. 30° E to 130° E, Lat. 30° S to 50° N

16 dBi

21 IRNSS Coverage

IRNSS Coverage Area HDOP & VDOP (99%) for the Proposed Constellaon GEO 34,83,132 GSO 55(55,235), 111(111,291)

User Mask Angle 5deg 22 Possible Expansions of IRNSS (Study)

23 IRNSS Signal Plan

Navigation Down Link Signals 24 IRNSS Signal Specificaons L5 S

SPS RS SPS RS

Centre Frequency (MHz) 1176.45 2492.028

Chipping Rate (Mcps) 1.023 2.046 1.023 2.046

Modulaon Type BPSK(1) BOC(5,2) BPSK(1) BOC(5,2)

Data/Symbol Rate (sps) 50 50 50 50

Bandwidth (MHz) 24 24 16 16

Min. Required Power (dBW) -159 -156 -162.3 -159.3

Max. Required Power (dBW) -154 -157.3

Max. Correlaon Loss (dB) 0.6 0.6 0.6 0.6

Jamming Margin (dB) 40 46 40 46 25 IRNSS Frame Structure

26 IRNSS Ground Segment

27 IRNSS Ionospheric Correcons vIonospheric effects on signal propagaon is the largest error source for single-frequency IRNSS users operang on L5. vFollowing figures show the total electron count (TEC) for a typical lines-of-sight on L5 over the course of a day.

Ionospheric delay comparison (dual- Ionospheric delay comparison (dual- versus single-frequency grid) on L5 versus single-frequency coefficient) on over 24 hours L5 over 24 hours 28 IRNSS Ionospheric Correcons

Posion errors for single-frequency user equipment Posion errors for single-frequency user equipment using grid-based correcons compared with dual- using coefficient-based correcons compared with frequency receivers dual-frequency receivers

RSS Posion Error at Bangalore and Bhopal Reference Staons with 4 IRNSS Satellites 29 IRNSS Network Timing System(IRNWT) The IRNSS ming facility generates the free running me scale is designated Free-(n), where ’n’ is either A or B depending on whether it is the online or backup system. The steered me scale is designated Steered-(n) or System me. The physical realizaon of the steered me scale is IRNWT, which is a leap second free me scale. This will be synchronized & steered to TAI from internaonal me lab maintained with in accuracy beer than 25ns at any instant of me over a year. This will be/ can also be called as TAI aer synchronizaon. IRNWT is normally delivered by the primary system, and it is delivered by the redundant system in case the primary fails.

30 Top level diagram of IRNWT facility configuration Applicaon Areas

Ø BIG (BHUVAN + IRNSS + Ø Feeding into the Flagship KEY AREAS GAGAN) Programs of India Ø Ganga Cleaning Mission: Ø Forest Fire Alert System Ø Visualizaon Mapping the River Bed and Ø Forest Cover Monitoring Ø Water Bodies and Ground Enre Basin Ø GIS-based Infrastructure Water Prospects Mapping Ø Crop Forecasng Planning Ø Traffic Control, Scienfic Ø Idenfying Potenal Fisheries Ø Geo-morphological Mapping Research and Security Zones for Mining Agencies Ø Wasteland Development Ø Mapping of Protected Areas Ø Disease Surveillance Ø Preparing Master Plan for and Coastal Zones Ø Micro and Mini Irrigaon and Cies Ø Toll Informaon System for Agricultural Projects Ø Satellites to provide Crical Naonal Highways Ø Micro and Mini Farming Data on Natural Resources of Ø Site Management Plan for Ø Weather and Ionospheric the Country Tourist Places under ASI, Geo- Studies Ø Environment Impact tagging and 3D Ø Geo Dynamics Assessment 31 HISTORY OF NAVIGATION

The great sanskrit scholar Kalidas (4th century A.D) was the first one to imagine above land navigaon. In his famous Sanskrit composion `Meghdoot’ , Kalidas’s Yaksha instructs `Megha’ ,how to navigate from Ramagiri to Alkapuri. He used complete Bio-Sphere as Navigaonal Control Points.

32 T H A N K S