Indian Satellite Navigation Programme

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Indian Satellite Navigation Programme

• N. G. Vasantha Kumar
• Dy. Director (Satnav ACS)
• Indian Space Research Organisation
• INDIA

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Basic Positioning Today
10-20 m

• Navigation satellites are Earth Satellites.
• Follow Keplers laws of motion, transmit their
  Position, Navigation, Time (PNT).
• Provide PNT service through hand-held receivers
  to users.
• Satellites orbits and health monitored through
  an elaborate ground segment.

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Global Satellite Navigation Systems
GPS
GALILEO
GLONASS
All Global Systems have more than 24 satellites
each in 19000 24000 km altitude orbits. All
transmissions from the satellite to date are in
L-band. The satellites transmit the ephemeris,
clock and ionospheric data. The details of the
signal structure and data structure vary
slightly. User receivers measure their distance
from at least 4 satellites through one-way
ranging technique. Most downlink signals use Code
Division Multiple Access (CDMA) and RF modulation
such as, BPSK, Binary Offset Carrier (BOC) etc.
GLONASS uses CDMA ranging codes with Frequency
Division Multiple Access (FDMA) These
constellations represent a wonderful laboratory
for fundamental scientific work
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Spectrum for GNSS

• GNSS spectral bands are
• L1 (1559 1610 MHz),
• L2 (1215 1300 MHz),
• L5 (1164 1215 MHz),
• S-band (2483.5 2500 MHz)
• L1 and L2 bands are being used for 30 years
  now.
• L5 is the latest and much sought after band.
• S-band is for Regional use in Region 3. The
  World Radio Conference (WRC-12) will discuss
  global allocation for this band.

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Radioastronomy 1610.6 1613.6 MHz
S
C
L2
L1
L5
E5
GPS
GPS
GPS
GLONASS
GLONASS
GALILEO
GALILEO
GALILEO
1260.000 MHz
1239.600 MHz
1215.000 MHz
1215.600 MHz
1237.827 MHz
1559.000 MHz
1261.610 MHz
1164.000 MHz
1188.000 MHz
1212.000 MHz
1300.000 MHz
1592.952 MHz
1610.000 MHz
1620.610 MHz
1626.500 MHz
1587.420 MHz
1563.420 MHz
5010.000 MHz
5030.000 MHz
2483.5 - 2500 MHz
Spectral bands for Radio Navigation Satellite
Systems
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GPS Augmentation systems in the World
2010(?)
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GAGANGPS Aided GEO Augmented Navigation
GAGAN is a Satellite Based Augmentation
System being implemented by India based on GPS
GAGAN jointly implemented by ISRO and Airports
Authority of India (AAI) GAGAN implementation
in two phases GAGAN TDS (Technology
Demonstration System) GAGAN FOP (Final
Operation Phase)
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GAGAN
OBJECTIVE To provide Satellite-based Navigation
services with accuracy and integrity required for
civil aviation applications over Indian Air
Space. Better Air Traffic Management over
Indian Airspace.
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GAGAN CONFIGURATION

• SPACE SEGMENT
• Three GEO Satellites
• Two operational Navigation Payloads
• One in-orbit spare Navigation Payload
• GROUND SEGMENT
• Indian Master Control Centre (INMCC)
• Indian Navigation Land Uplink Station (INLUS)
• Indian Reference Stations (INRES)
• Communication links

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GAGAN NAVIGATION SIGNALS
GAGAN Space Segment uses SBAS PRN codes 127 and
128 to transmit corrections and integrity
parameters to SBAS receiver. Signals Received by
GAGAN Receiver
Signals Frequency Band
1 MHz BPSK L1 (1575.42 MHz)
10 MHz BPSK L5 (1176.45 MHz)
When GPS L5C is available
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GAGAN CONFIGURATION
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GAGAN INTENDED SERVICES

• High position accuracies with integrity (APV-1.5
  or better) over a wide geographical area such as
  the Indian Airspace.
• These position accuracies to be simultaneously
  made available to all airports and air fields in
  Indian FIR, enabling satellite based landing of
  aircraft fitted with SBAS receivers.
• To provide fuel efficient air corridors.
• Better upper Air-space management over India.

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IRNSS Indian Regional Navigation Satellite System

• IRNSS is an independent regional navigation
  system
• 7 satellite constellation and ground segment.
• Coverage area is about 1500 km beyond Indian
  territory.
• Estimated horizontal position accuracy of 10m in
  over India and adjoining areas.

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IRNSS Indian Regional Navigation Satellite System

• OBJECTIVES
• Reliable Position, Navigation and Timing services
  over India and its neighbourhood
• To provide fairly good accuracy to the user.
• Most of the constellation is seen by user all the
  time.
• Integrity and ionospheric correction messages to
  user.

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IRNSS CONFIGURATION
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IRNSS SPACE SEGMENT
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IRNSS SPACE SEGMENT

• 3 GSO satellites at 340, 830, and 131.50 East.
• 4 Inclined GSO satellites at 290 inclination with
  Longitude crossing at 550 and 111.50.
• To be launched by Indian PSLV.
• First satellite launch by second half of 2011.
• Full constellation completion by 2014.
• Space segment will be augmented with 4 more
  satellites to make 11 satellite constellation
  with better coverage and accuracy.

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IRNSS- GROUND SEGMENT Architecture

• IRNSS Navigation Control Facility ( IRNCF )
• IRNSS Navigation Centre ( INC )
  
• IRNSS Network Time ( IRNWT )
  
• IRNSS CDMA Ranging Stations ( IRCDR )
  
• IRNSS Laser Ranging Service ( ILRS )
• IRNSS Range and Integrity Monitoring Stations
  
• IRNSS Data Communication Network (IRDCN)
• IRNSS Satellite Control Facility ( IRSCF )
• IRNSS TTC Land Uplink Stations (INLUS)
  
• IRNSS Satellite Control Centre ( IRSCC )
  

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IRNSS- GROUND SEGMENT Architecture
IRNWT
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IRNSS NAVIGATION SIGNALS
SPS RS
L5 (1176.45 MHz ) BPSK BOC (5,2)
S band (2492.028 MHz) BPSK BOC(5,2)

• CDMA Ranging Frequencies
• Uplink 6712 .0MHz (B.W 24MHz)
• Downlink 3412 .0 MHz (B.W 24MHz)

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IRNSS NAVIGATION SIGNALS
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THANK YOU
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GNSS- Aviation Alert Limits
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GNSS- Aviation Operational Performance
Requirements
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IRNSS Data Structure
Master Frame
SUBFRAME 1 SUBFRAME 2 SUBFRAME 3 SUBFRAME 4
300 BITS 300 BITS 300 BITS 300 BITS
Sub Frame
1 23 45 277
TLM HOW DATA CRC
22 BITS 22 BITS 232 BITS 24 BITS
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GAGAN PAYLOAD CHARACTERISTICS
L5 Freq. (1176.45 MHz)
L1 Freq. (1575.42 MHz)
System characteristics
Sl. No.
29.2 dBW
30.2 dBW
Transmit EIRP (EOC)
1.
-2 dB/deg.K
Receive G/T
2.
-2 dB/deg.K
24 MHz
20 MHz
Bandwidth
3.
Global
Global
Footprint
4.
C-band
Feeder Link frequency
5.
C-band
RHCP
RHCP
Transmit polarisation
6.
Helix
Type of Antenna
7.
Helix
15.8 dB
Antenna Gain
8.
15.8 dB
40W
RF Power rating
9.
40W
50 Kg

Total Payload weight
10.
240W
Power D C
11.
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IRNSS- GROUND SEGMENT Architecture

• IRNSS Navigation Control Facility ( IRNCF )
• IRNSS Navigation Centre ( INC )
  - 2 Nos
• IRNSS Network Time ( IRNWT )
  - 2 Nos
• IRNSS CDMA Ranging Stations ( IRCDR )
  - 4 Nos
• IRNSS Laser Ranging Service ( ILRS )
• IRNSS Range and Integrity Monitoring Stations
  -16 Nos
• IRNSS Data Communication Network (IRDCN) - 2
  Nos
• IRNSS Satellite Control Facility ( IRSCF )
• IRNSS TTC Land Uplink Stations (INLUS)
  - 9 Nos
• IRNSS Satellite Control Centre ( IRSCC )
  - 2 Nos

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Challenges in Technology

• Astronomy ( Orbital Mechanics )
• - Precision Orbits, Accurate Ephemeris
  determination
• Signal structure Modulation and Codes
• Stable On-board atomic clocks and their
  estimation
• Atmospheric Science Modeling delays
• GNSS Receiver technology, indoor positioning
• The ICE (Ionosphere, Clock, Ephemeris) errors
• Hazardously Misleading Information (HMI)
• GAGAN certification, Software standards
• Safety of Life system Software and its
  certification

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Applications of Satellite Navigation systems
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Satellite Communications and Navigation programme
of ISRO/DOS

• Leadership in Satellite Communication
  demonstrated through the deployment of the INSAT
  system since 1982.
• Leadership in Satellite Navigation through
  deployment of GAGAN and IRNSS to be demonstrated
  in this decade. GAGAN is an AAI-ISRO Project.
• Continue to maintain leadership in these areas to
  serve India and its people.
• Develop technical and human resources to address
  technology issues. Coordinate and use spectrum.
• Satellite based communication and navigation
  systems for rural connectivity, security needs
  and mobile services.