Project Report on

Satellite Communication in ONGC

SUBMITTED BY:

Name: PRIYA APTE

Branch: Electrical Engineering

Roll No.:1101EE05

INDIAN INSTITUTE OF TECHNOLOGY PATNA

Training Period: 05/05/2014 TO 30/06/2014

CERTIFICATE

This is to certify that Priya Apte has completed the Summer

training on “Satellite Communication in ONGC” during 05th May 2014 to

30th June 2014 at ONGC Vasundra Bhavan,Bandra(East) under the

guidance of Vikas Shinde, Chief Engineer (E &T),ONGC Mumbai.

(Vikas Shinde)

C.E .(E&T),ONGC

ACKNOWLEDGEMENT I sincere acknowledgement to Oil and Natural Gas Corporation

Limited for giving me valuable opportunity to work with them. This

project report is dedicated to all the people, whom I met, took guidance,

talked and gained knowledge from them.

I also express my sincere thanks to Mr. K. C. Ghosh ,C.E.(Inst.)

,ONGC,Mumbai and Mr. D.K. Dhiraj ,DGM (E&T),ONGC ,Mumbai for

providing us conductive environment and allowing us to reach desired

accomplishment.

With warm regards I would like to thank my project mentor

Mr.Vikas Shinde C.E.(E&T),ONGC ,Mumbai for the encouragement and

guidance continuously provided by him to undergo my summer training

in this esteemed organization .

I would like to thank all the staff ONGC, Mumbai for being so

helpful during this summer internship.

Lastly, I thank almighty , my parents for their constant

encouragement and support without which this project would not be

possible .

About the company Oil and Natural Gas Corporation Limited (ONGC) is an

Indian multinational oil and gas company headquartered

in Dehradun, India.

It is one of the largest Asia-based oil and gas exploration and

production companies.

produces around 77% of India's crude oil(equivalent to around

30% of the country's total demand) and around 81% of its natural

gas.

ONGC has been ranked 357th in the Fortune Global 500 list of the

world's biggest corporations for the year 2012.

It is also among the Top 250 Global Energy Company by Platts.

ONGC was founded on 14 August 1956 by the Indian state, which

currently holds a 69.23% equity stake.

. Its international subsidiary ONGC Videsh currently has projects in

15 countries.

A Brief on ONGC’s Mumbai High Asset Mumbai High is biggest oil & gas field in Western offshore .

The field is located about 165 kilometers away in Arabian Sea at a

water depth of 70 to 80 meters.

The field was discovered in 1974 by the legendary rig Sagar Samrat.

The field was put on commercial production in 1976. The field has

developed with mammoth infrastructure for Oil & Gas production,

process and export.

The field producing currently about 2,60,000 barrels of oil per day,

about 15 mms cmd of sweet gas besides injecting nearly 10,00,000

barrels of water per day into the reservoir.

ONGC has its own telecommunication network which connects its

HQ at Dehradun to all regional offices located all over India, Offshore

Rigs & Process Platforms.

- (Ref. : www.ongcindia.com)

What is Satellite Communication?

Satellite Communication operates in Microwave frequency Band

and can be considered as a Repeater placed in Space.

It consist of ground-based or Earth stations (i.e. parabolic

antennas) and orbiting transponders which receives signal from the

ground unit (uplink) amplifies it and then transmits it back to earth

(downlink).

Large coverage area across terrestrial boundaries, cost is

independent of the distance.

How do Satellites work? An Earth Station sends message in GHz range. (Uplink)

Satellite Receive and retransmit signals back. (Downlink)

Other Earth Stations receive message in useful strength area.

(Footprint)

Microwaves are electromagnetic waves with frequency from

30MHz to 1 GHz. The ionosphere cannot reflect microwaves back

to the earth. They pass through the ionosphere. A satellite used to

receive microwaves and then transmit them back to the earth.

Satellites provide links in two ways. Firstly a satellite provide point

to point communication link between one ground station and the

other.

One ground station transmit signal to the other satellite and next

ground station receives them from the satellite. Secondly, satellite

receives signals from one ground station and transmits to them to

the number of ground receivers.

Most satellite use frequency bandwidth through from 5.92 to

6.4GHz from transmission of data from earth to the satellite and a

frequency bandwidth from 3.7 to 4.1GHz for transmission from

satellite to the earth.

Types of Satellites Anti-Satellite weapons sometimes called "Killer satellites" are

satellites designed to destroy "enemy" satellites, other orbital weapons and targets.

Astronomical satellites are satellites used for observation of

distant planets, galaxies, and other outer space objects. Biosatellites are satellites designed to carry living organisms,

generally for scientific experimentation. Communications satellites

are an artificial satellite stationed in space for the purposes of telecommunications.

Modern communications satellites typically use geosynchronous orbits, Molniya orbits or low Earth orbits.

Navigation satellites are satellites which use radio time signals

transmitted to enable mobile receivers on the ground to determine their exact location.

A communications satellite is a satellite located in space for the purposes of telecommunications.

There are three altitude classifications for satellite orbits: LEO – Low Earth Orbit

LEO satellites orbit from 160-2000km above the earth, take approximately 1.5 hrs for a full orbit and only cover a portion of the

earth’s surface, therefore requiring a network or constellation of satellites to provide global, continual coverage. Due to the proximity to Earth, LEO satellites have a lower latency (latency is the time between the moment a packet is transmitted and the moment it reaches its destination) and require less amplification for transmission.

MEO – Medium Earth Orbit MEO satellites are located above LEO and below GEO satellites and typically travel in an elliptical orbit over the North and South Pole or in an equatorial orbit. These satellites are traditionally used for GPS navigation systems and are sometimes used by satellite operators for voice and data communications. MEO satellites require a constellation of satellites to provide continuous coverage. Tracking antennas are needed to maintain the link as satellites move in and out of the antenna range. GEO – Geostationary Orbit

GEO satellites orbit at 35,786 km (22,282 mi) above the equator in the same direction and speed as the earth rotates on its axis. This makes it appear to the earth station as fixed in the sky. The majority of commercial communications satellites operate in this orbit; however, due to the distance from the earth there is a longer latency.

Satellite Orbits

GSAT 10 GSAT 10 communication satellite is presently used by Oil and

Natural Gas Corporation Limited ,Mumbai.

GSAT-10, India’s advanced communication satellite, is a high power

satellite being inducted into the INSAT system.

GSAT-10 was launched by Ariane-5ECA carrier rocket in September

2012.

It has 12 KU Band, 12 C Band and 6 lower extended c band

transponders.

GSAT-10 also carries a Ku-band beacon to help in accurately

pointing ground antennas towards the satellite.

Features: Spacecraft design -ISRO

Orbital location -83 degree east

Orbit -Geostationary , co-located with

INSAT-4A and GSAT-12

Vehicle -Ariane-5 VA-209

Design life -15 yrs

Power - Solar array providing 6474 Watts (at

Equinox) and two 128 AH Lithium-

Ion batteries

Transponder -12 ku –band ,12 c-band, 6 lower extended

c-band

Launch mass(kg) -3400 Kg

Dry mass(kg) -1498 Kg

Model(bus) - insat-2/-3

Frequency Bands Different kinds of satellites use different frequency bands.

1)L-Band 1 - 2 GHz

2)S-Band 2 - 4 GHz

3)C-Band 4 - 8 GHz

4)X-Band 8 - 12 GHz

5)Ku-Band 12 - 18 GHz

6)K-Band 18 - 26.5 GHz

7)Ka-Band 26.5 - 40 GHz

8)Q-Band 30 - 50 GHz

9)U-Band 40 - 60 GHz

10)V-Band 50 - 75 GHz

11)E-Band 60 - 90 GHz

12)W-Band 75 - 110 GHz

13)F-Band 90 - 140 GHz

14)D-Band 110 - 170 GHz

C band – uplink 5.925-6.425 GHz; downlink 3.7-4.2 GHz: The C band is primarily used for voice and data communications as well as backhauling. Because of its weaker power it requires a larger antenna, usually above 1.8m (6ft). However, due to the lower frequency range, it performs better under adverse weather conditions on the ground.

Ku band– uplink 14 GHz; downlink 10.9-12.75 GHz Ku band is used typically for consumer direct-to-home access, distance learning applications, retail and enterprise connectivity. The antenna sizes, ranging from 0.9m -1.2m (~3ft), are much smaller than C band because the higher frequency means that higher gain can be achieved with small antenna sizes than C-band. Networks in this band are more susceptible to rain fade, especially in tropical areas.

Satcom Technology (In ONGC)

FDMA

FAMA-FDMA

DAMA-FDMA

TDMA

Advantages over FDMA

FDMA- Satellite frequency is already broken into bands and is broken in to

smaller channels in frequency division multiple access.

Overall bandwidth and frequency band is increased due to frequency

reuse.

The number of sub channels is limited by three factors:

Thermal noise (too weak signals will be effected by background noise).

Intermodulation noise (too strong a signal will cause noise).

Crosstalk (cause by excessive frequency reusing).

FDMA can be performed in two ways :

Fixed assignment multiple access(FAMA):

The sub channel assignments are of a fixed allotment .Ideal for broadcast

satellite communication .

Demand assignment multiple access(DAMA):

The sub channel allotment changes based on demand. Idea for point to

point communication.

TDMA- TDMA (Time Division Multiple Access) breaks a transmission into

multiple time slots , each one dedicated to a different transmitter.

TDMA is increasingly becoming more widespread in satellite

communication.

TDMA uses the same technique (FAMA and DAMA) as FDMA does.

Advantages of TDMA over FDMA Digital equipment used in time division multiplexing is increasingly

becoming cheaper.

Lack of intermodulation noise means increased frequency.

Evolution of SATCOM in ONGC OPSNET:

In 1982-83, two Satellite Earth Stations at Uran and BHN (offshore) were

established under ‘Titan’ project in Mumbai. Subsequently three more

SES at Hazira, BPA and Heera were setup during mid/late 80’s.

TELNET:

During early 90’s 5 more SES were installed at DDN, BDA, NZR, AGT, JDR

and RJY. Two SES of DOT at KOL, Chennai and NTPC Delhi Were used.

ICNET:

During 2000, VSAT based SATCOM network was established to cover 21

locations for providing voice and data circuits.

MFTDMA – C-band VSAT:

During 2008-09, MFTDMA based SATCOM network was established to

cover the field installations like Production Installations, Geophysical

Field Parties, and Drilling Rigs.

Introduction to VSAT

A class of Very Small Aperture Terminal,

Intelligent satellite earth station,

Suitable for easy on-premise installation,

Capable of supporting a wide range of two-way, integrated

telecommunication and information services.

consisting of hub, a relatively large central station and many VSAT

(remote) earth stations

network with star/ mesh topology

Data rate - low to medium bit rate (<= 2 Mbytes/sec)

Ku (14/11-12 GHz) and C (6/4 GHz) operation

MFTDMA BASED C-BAND VSAT The project was based on MF-TDMA technology, covers 183 Satcom

locations & 25 radio links spread across the country. Under the project

the following installations have been provided with Satcom links.

o Production installations at various Assets (3.8m/ 2.4m)

o Geophysical Field Parties (2.4m)

o On-shore Drilling Rigs (2.4m)

o Augmentation of 8 off-shore Drilling Rigs

Based on IP technology, capable of handling fast data rates and

provide a highly reliable and bandwidth efficient solutions for Voice

& Data communication.

Providing communication links between the field locations and

their respective Assets/Basins for Enterprise Wide on-line SCADA

to facilitate analysis of valuable well / Process data and Drilling data

available in the SCADA servers.

To ensure access to various corporate wide I.T. applications like

SAP, Intranet/internet, e-mail from these field installations.

COMMUNICATION NETWORK IN ONGC

(Schematic)

Equipments used in Voice and Data Communication EPABX(for voice)

MUX

MODEM(modulator & demodulator)

ROUTER(for data)

UP-CONVERTER

DOWN-CONVERTER

SSPA(solid state power amplifier)

LNA(low noise amplifier)

ANTENNA

Electronic Private Automatic Branch Exchange(EPABX) A private branch exchange is a telephone exchange that serves a

particular business or office (in our case, ONGC). This is the

opposite of one that a common carrier or telephone company

operates for many businesses or for the general public.

The EPABX in the above used system is only for the transmission

and the reception of the voice signals via the satellite.

The EPABX makes connection among the internal telephones of

a private organization (ONGC) and also connect them to the public

switched telephone network (MTNL) as also to the satellite

network as shown in the above case.

Multiplexer (MUX) A MUX or a multiplexer combines the many voice signals into a

single path and gives the output to the modem.It is used only for

the voice signals and not for the data signals.

For eg.,in telecommunication ,several telephone calls may be

carried using one wire.

A process known as demultiplexing can extract the original signals

on the receiver side.

Generally the MUX used is of the brand (3600/3600+ Mainstreet

Company Alcatel).There are various cards that are used and fitted

in the MUX used as follows

3600 mainstreet alcatel mux

ONGC uses this mux for satellite communication . This mux consists of

the following cards:

V.35 PRI-connected to modem

V.35 –for data communication

DSP-handles configuration of circuits

E&M(ear & mouth)

DAP card

Control card-controls entire system

Up Converter A radio frequency up-converter is a device that takes an input of

intermediate frequency energy of a specific frequency range and

outputs it on a higher frequency.

The up-converters are designed for use in the communication

systems or in the satellite uplink data systems (like here) for the

transmission of SCPC, DAMA and TDMA communication signals.

The up-converter used in the satellite communication system

above is the Comtech UT 4505.

Upconverter-UT-4505

The RF output frequency range for the up-converters used here is

5845-6425 MHz

Upconverter converts IF to RF frequency .

Eg.Upconverter converts 70MHz to 6175MHz for C band

application.

Down Converter A radio frequency down-converter is a device that takes an input of

higher frequency energy of a specific frequency range and outputs

it on a intermediate frequency.

The down-converters are designed for use in the communication

systems or in the satellite uplink data systems (like here) for the

reception of SCPC, DAMA and TDMA communication signals.

The down-converter used in the satellite communication system

above is DT-4503.

Downconverter-DT-4503

The RF output frequency range for the down-converters used in the

system is the same as up-converters and is given as

5845-6425 MHz

Downconverter converts RF to IF frequency .

For eg.Downconverter converts 3950MHz to 70MHz for C band

application.

Splitter/combiner and codec

It eliminates the need for extra wiring thereby reducing the cost of

installation.

A codec converts analog input into digital format and vice versa.

Modem

It performs modulation and demodulation on transmit and receive

side.

Digital signals are modulated to take full advantage of existing

circuitry,eg.in telephone lines.

Modulation refers to the method of changing the carrier signal with

respect to the message signal.

• The modem used for our satellite communication is the Radyne

Corporation DMD2401 Satellite Modem.

• Modulator inserts information on intermediate

frequency(IF),usually called carrier.This is done based on

modulation scheme set.Usually QPSK scheme is used.

• In order to communicate between VSAT1 and VSAT2,modulation

frequency of VSAT1 and demodulator frequency of VSAT2 need to

be same.

Types of modulation: Amplitude shift keying(ASK):Uses one amplitude at a fixed

frequency to convey a logic high(1) and zero amplitude to convey a

logic low(0).

Frequency shift keying(FSK):One frequency is used to show logic

high and another is used to show logic low.

Phase shift keying(PSK):It relies on transmitter and receiver being

perfectly synchronized so that reference used by demodulation process

is same as that for modulation.

Router(CISCO 3600 & 7200 series)

A wide area network (WAN) is a network that covers a broad area

using leased telecommunication lines.

ONGC utilize WANs to relay data among employees from various

geographical locations.

In essence, this mode of telecommunication allows a business to

effectively carry out its daily function regardless of location.

Router is a device that determines the next network point to which

a packet must be forwarded towards its destination.

Solid State Power Amplifier (SSPA) Solid state power amplifiers are usually divided into low power

driver sections and high power output stages.

Gallium Arsenide Field Effect Transistors (GaAs FET) are used for

power amplification.

To obtain high powers, many stages are fed in parallel from a

medium to high power amplifier and combined at the output

These C band high power amplifiers (100 through 250 watts)

provide the linearity and gain stability required for earth station.

The SSPA used here is ADVANTECH ARMA C-200 watt.

Features:

Frequency range: 5.85 to 6.425 GHz

Output Power @ 1dB Gain compression is 50.6 dBm

Temperature compensation

20 dB Gain adjustment

1:1 Redundant system

Low Noise Amplifier (LNA) The low noise amplifier (LNA) is a special type of electronic

amplifier or amplifier used in communication systems to amplify

very weak signals captured by an antenna.

It is often located very close to the antenna. If the LNA is located

close to the antenna, then losses in the feed line become less

critical.

It is a key component, which is placed at the front-end of a radio

receiver circuit. Using an LNA, the noise of all the subsequent

stages is reduced by the gain of the LNA and the noise of the LNA

is injected directly into the received signal. Thus, it is necessary for

an LNA to boost the desired signal power while adding as little

noise and distortion as possible so that the retrieval of this signal is

possible in the later stages in the system.

The LNA used here is a LOCUS Lnac-1100-7.

Antenna

The 6.3 meter earth station scientific antenna meets international

specifications is deployed at Vasundhara Bhavan hub Station.

The reflector consists of 40 dual shaped panels placed in 3 rows

over 16 trusses emanating from a center hub.

The antenna features shaped cassegrain paraboloid configuration

with a conical corrugated horn, sub-reflector and shaped reflector.

The center hub is spacious to accommodate receive electronic

equipments.

Parabolic antenna

It uses a parabolic reflector , a curved surface with the cross

sectional shape of a parabola ,to direct the radio waves.

Uses:

satellite communication

used in radio telescopes

radar antennas to transmit a narrow beam of radio

wireless WAN/LAN

ONGC uses cassegrain antenna:

9metres

Transmission: horizontal polarisation

Reception: vertical polarization.

The Cassegrain Antenna

In telecommunication and radar use, a Cassegrain antenna is an

antenna in which the feed radiator is mounted at or near the

surface of a concave main reflector and is aimed at a convex

subreflector.

Both reflectors have a common focal point. Energy from the feed

unit (a feed horn mostly) illuminates the secondary reflector, which

reflects it back to the main reflector, which then forms the desired

forward beam.

SUMMARY All applications in ONGC are supported through a star/mesh WAN

infrastructure spread across the country, interconnecting all offices

and field locations using a combination of connectivity mediums

like hired terrestrial leased lines, ISDN, satellite, and radio links.

Major work centers across the country are connected to regional

gateway offices using intercity leased line, satellite, or radio links.

Communication network in ONGC allow geographically dispersed

personnel to collaborate with subject matter experts and other

human resources from a distance through voice and data

communication as well as video conferencing.

As operations expand and move increasingly to offshore and other

challenging environments, it will provide the ability to monitor rig

operations remotely while improving safety, helping reduce costs

and, ultimately, enabling them to make better decisions.

Conclusion Infrastructure of the organization has kept pace with evolving

technologies. HF/ VHF radio communications, point to point microwave links, point to multipoint TDMA network, TDM/ TDMA, MF-TDMA access techniques, have been installed from time to time to meet the voice and data connectivity requirements at remote locations.

In the present deployment in ONGC, redundancy for sector and power supply was conceived and implemented.

Reference 1. www.ongcindia.com

2. www.isro.org

3. Behrouz A.Forouzan:Data communications and networking(4th

edition),McGrawHill

4. Onsite visit at ONGC,Mumbai