Alvin Toffler‟s “Future shock” (1970)

•1800 Discovery of infrared by Sir William Herschel

•1839 Beginnings of photography

•1850 Aerial photography using balloons

•1909 Photography from aircraft

•1972 Launch of Landsat

•1970s - 1990s: Rapid development of digital image

processing and launch of high resolution satellite

sensors

•Today ….. >125 Satellites in operation ; 90 satellites

planned for launch in next 4 years ...... CEOS Report

‘Too much change in too short a period of time’.

NASA‟s Earth Resources Technology satellite – later named

„Landsat‟ launched in 1972 was the first civil RS satellite.

“ In early 1990s the national Earth remote sensing systems were

operated by six countries (USA, China, France, India, Israel and

Japan), this number constituted 20 in 2000 and presently there

are over 30.

Current plans supplied by CEOS agencies estimate that around 90 new

satellite missions will be launched for operation between 2014 and

2018. The next few years mark a significant era for satellite Earth

observations, with more then half of these new missions to be

launched by the end of 2015.

Future Missions

China‟s FY-3 series

Korea‟s COMS series

The NOAA series of polar-orbiting satellites

EUMETSAT will launch further MetOp series

Meteosat Third Generation – Imagers & Sounders

ESA Sentinel-4 UVN mission

GCOM series (JAXA), OCO-2 (NASA) and EarthCARE (ESA/JAXA).

ADM-Aeolus (ESA) will provide new information on winds.

• AGRICULTURE & CROPS

• FOREST & BIO-RESOURCES

• WATER RESOURCES

• GEOLOGY

• OCEAN/COASTAL

• ENVIRONMENT

• RURAL DEVELOPMENT

• URBAN MANAGEMENT

• CARTOGRAPHY/MAPPING

• CLIMATE MODELLING

• GLOBAL CHANGE

INFORMATION TO SOLUTIONS

INSAT-2E

VHRR, CCD (1 KM)

INDIAN IMAGING SYSTEMS

1999

IRS-P2

LISS-2

IRS-1A & 1B

LISS-1&2 (72/36M)

BHASKARA VIDICON, SAMIR

RS-D1 SMART SENSOR

1979/81

1982

1988/91

1994

INSAT-1D

VHRR

INSAT-2A

VHRR

Geo stationary missionsPolar missions

1992

1990

IRS-1C/1D LISS-3 (23/70M,

STEERABLE PAN (5.8 M);

WiFS (188M)

IRS-P3

WiFS, MOS X-Ray

1996

1995/1997

IRS-P4 (OCEANSAT-1)

OCM, MSMR

1999

TES

STEP & STARE CONCEPT

2001

INSAT-2B

VHRR 1993

KALPANA-1

VHRR – 2 Km(vis);

8 Km(IR & WV)

2002

P band : 0.3 - 1 GHz (30 - 100 cm)

L band : 1 - 2 GHz (15 - 30 cm)

S band : 2 - 4 GHz (7.5 - 15 cm)

C band : 4 - 8 GHz (3.8 - 7.5 cm)

X band : 8 - 12.5 GHz (2.4 - 3.8 cm)

Ku band : 12.5 - 18 GHz (1.7 - 2.4 cm)

K band : 18 - 26.5 GHz (1.1 - 1.7 cm)

Ka band : 26.5 - 40 GHz (0.75 - 1.1 cm)

Pointing knowledge can sometimes be improved after the

fact, such as by monitoring the earth’s magnetic field and

later post-processing the output of a magnetometer for

better knowledge of a telescope’s pointing direction for a

particular photograph.

Pointing Stability

When given as a requirement, this is the maximum rate of

change of angular orientation allowed.

Jitter

Jitter refers to the errors in attitude of a frequency too high

to be controlled by the attitude control system. When given

as an attitude control performance requirement, it is a

specified angle bound or angular rate limit on short-term,

high-frequency motion of the spacecraft.

Pointing accuracy affects location accuracy

Angular velocities (drift rates) distorts image and affects pixel

registration

Jitter affects the resolution

Push-broom scan

• High SNR due to increased ‘dwell time’

• High geometric fidelity/accuracy

• Lower size optics – less volume, weight

• High reliability due to no moving parts and solid state technology

• Better MTF without scan mirror

Whisk-broom scan

• Less dwell time results in poorer SNR

• Scan mirror non-linearity introduce geometric errors

• Large aperture optics – more volume & weight

• Moving element - less reliable system

For

TV camera - 16 kbps

LISS - 1 - 5.2 Mbps

PAN - 105 Mbps

SAR - 360 Mbps

intT

BPbDR

Where; b is no.bits/pixel , P is no.of pixels

per band & B is no. bands Tint is

Integration time.

Payload Data Rate

sec/sec

bits

bandsbands

pixel

pixel

bits

DR

On-board storage capacity

11.375 1.375

2.75

7.33

1 1.375 1.3752.75

55

0

10

20

30

40

50

0

1

2

3

4

5

6

7

8

INSAT 1 INSAT 2 Kalpna INSAT 3D GISAT

Imp

rove

me

nt

in V

is R

es

olu

tio

n w

rt IN

SA

T 1

Imp

rove

me

nt

in IR

Re

so

luti

on

wrt

IN

SA

T 1

IR VisDoD: 1980 DoD: 1991 DoD: 2002 DoD: 2010 DoD: 2017/18

Improvement in Ground Resolution

Compared to INSAT 1 VHRR:

IR: 7.3 times

Visible: 55 times

200 200 200

300

700

0

100

200

300

400

500

600

700

800

INSAT 1 INSAT 2 Kalpna INSAT 3D GISAT

Te

les

co

pe

Dia

(mm

)

Missions

2 23

6

12+2 HyS

0

2

4

6

8

10

12

14

16

INSAT 1 INSAT 2 Kalpna INSAT 3D GISAT

Nu

mb

er

of

Ban

ds

Missions

INSAT 1 , 0.4

INSAT 2 , 0.525

Kalpna , 0.525

INSAT 3D, 4

GISAT, 200

0.1

1

10

100

0 1 2 3 4 5 6Data

Rate

(M

bp

s)

Missions

Good spatial resolution, Poor temporal resolution.

Good temporal resolution,Poor spatial resolution.

Mission…

Evolution:LEO platform Good spatial resolution,

Poor temporal resolutionGEO platform Good temporal resolution

Poor spatial resolution,That’s how GISAT was conceived with thefollowing objective…….“To tap new functionalities hitherto not coveredby existing LEO & GEO Missions like Fast revisitcapability, real time monitoring, high resolutionmulti spectral and Hyper spectral imaging - allon a single, agile, jitter free platform”

Basic applications of Payload are monitoring of Disasters, Natural hazards and calamities Episodic and Short term events etc. Spectral signatures for agriculture, forestry, mineralogy, oceanography Meteorological applications, including nowcasting

To meet these mission objectives, following baselinerequirements are contemplated:

Four Imaging channels - Multi-spectral (MX) VNIR & LWIR, Hyper spectral(HX) VNIR & SWIR

The basic telescope of CARTO-2A type with necessary modifications

The spacecraft to be agile, to enable bi-directional scanning

Electronically steerable antenna/ PAA is considered

Platform Jitter & drift rate is critical

Stringent thermal requirements

Spacecraft Mission life of 7 years, and Design life of 15 years (Radn shielding)

Launch compatibility with : (i)GSLV MK-II & (ii)Commercial launchers

Spacecraft Dry mass estimate : 1000 kg

Spacecraft Lift-off mass : 2100 kg

Deployment after T0+100sec (based on 3D flight experience)

Evolution and Milestones….…

1.5

52

m

YAW

PITCH

YAW

PITCH

Thermal Heater

Cylinder

Kevlar

Hood

North Panel With E-W

dedicated Radiators

West Panel

Fuel Tank-2

Fuel Tank-1

East Panel

South Panel With E-W

dedicated Radiators

Thrust

Cylinder

Stiffener

Panels

AEV

Panel

I/F-Ring

LAM Mnt

Deck

LAM

Heat

Shield

LAM

Star Sensor-3

East Thrusters

EOM Payload

EOM Payload PFD

I/F Ring

Thrust Cylinder

Cylinder

Closing Deck

EOM Payload Interface on

Cylinder Top Ring

with Gussets (3 No.’s)

Thrust

Cylinder Top

Ring

Thrust

Cylinder

Payload Attachment To Main Bus Structure

Inside Cuboid

Structure

EOM Payload

Modified I-1K bus, Structure size [1.552(N-S) x 1.65 (E-W) x 1.7 (EV-AEV) ]m3

1.5m hood height (Kevlar – RF transparent)

Thermal control system is sized to handle about 1000 Watts overall dissipation

Keep-off time of Payload operation: of 1hr in Equinox at Local mid-night due to sunintrusion

(8 nos. x 22N +8 nos. x 10N) thrusters are configured

No NSSK requirement for GISAT

Zero momentum biased control system [5 nos. of RW with angular momentum 15Nms& torque of 0.3Nm @3500 rpm ]

OBC with LEON-3 processor

Magnetic Torquers with dipole moment of 1000 Am2

Star Sensors : Mark-3 type (3CHUs + 2APUs) & SPSS – 2 nos., CASS – 8 nos.

LIRU / FOG (TBD)

Micro-stepping SADA

Single sided solar array with 3 panels (of standard I-2K size -2.54m*1.525m).

Auto deployment of Solar Panel after injection in GTO

Single bus system, 90Ah Li-ion battery for eclipse operations

Synthesized TTC-RF systems, with Medium Gain Antenna (beam width 25)

No NSSK is planned, but margin exists

High Resolution Imaging Sensors on GEO Platform

Multi-spectral VNIR (6 Bands) Ground Resolution : ~ 50 m(0.45-0.52 µm, 0.52-0.59 µm, 0.62-0.68 µm, 0.71-0.74 µm, 0.77-0.86 µm, 0.845-0.875 µm)

Multi-Spectral LWIR (6 Bands) Ground Resolution : ~ 1500 (7.1-7.6 µm, 8.3-8.7 µm, 9.4-9.8 µm, 10.3-11.3 µm 11.5-12.5 µm, 13-13.5 µm )

Hyper-spectral VNIR (60 Bands) Ground Resolution : <500

(0.4-0.87 µm, < 10nm)

Hyper-spectral SWIR (150 Bands) Ground Resolution : <500 m(0.9-2.5 µm, < 10nm)

Coverage

Area

N-S step

angle ()

Number of

E-W strips

Scan rate

(/s)Time (min.)

1010 0.58 18 0.4 17

55 0.58 9 0.4 7

Yaw

Roll

Pitch

Earth

Telescope, structure, hood, field correcting optics (FCO), spectrometers, array

detectors, cooler assemblies, camera electronics, control and data handling

electronics, power electronics

PRIMARY MIRROR 700 mm

SECONDARY

MIRROR

FCO

HyS-VNIR

HyS-SWIR

MX-VNIR

MX-LWIR

FORE OPTICS AFT OPTICS FOCAL PLANES

RADIATION

FROM EARTH

Sec. Mirror

CFRP Cylinder

PFD –Payload Fixation Device

Telescope mounting interface with S/c

Optical bench

Prim. Mirror

The collecting optics

is based on

CARTOSAT-2A type

telescope with

700mm aperture

and nearly 5625 mm

effective focal

length.

IGFOV varied from

50 m to 1.5 km

whereas it is 1 km

for VNIR (CCD) for

Kalpana-1 & INSAT-

3A and 8km for

LWIR. For INSAT-3D

it is 4 km for LWIR.

Platform stability & operational requirement-S/c pointing accuracy : 0.05 deg in all axes-Drift rate : 5 X 10-5 deg/sec-Jitter requirement : <0.15 µrad (total)-Scan rate : 0.004 – 0.4 deg/sec-Turn around time : <30 secs-House-keeping (including SADA) : <5 min every 0.5 hours

Payload Operating Temperature requirements- HYS SWIR Detector : 273 K- SWIR IDCA window +Baffle : 273 ± 0.1 K- MX LWIR Detector : 240 K- LWIR FCO & IDCA window : 240 ± 0.15 K- IDCAs case (LWIR, SWIR) : 22 ± 5 deg C- MX -VNIR, HYS - VNIR Detector : 22 ± 2 deg C- Temperature gradient across telescope : <5 deg. C

Freq.

(Hz)

Integrated

rms jitter

(°)

> 2 < 1.9E-4

> 8 < 5.1E-5

> 13 < 3.1E-5

> 60 < 6.6E-6

Payload Requirements….…

VIEW FROM AEV SIDE OF OPTICAL BENCH, PAYLOAD

HEAT PIPES MOUNTEDBELOW PACKAGES

HEAT PIPES CONTECTEDWITH N/S RADIATORS

AFT OPTICAL BENCH VIEW

Thermal Deck

PM Support deck

Thermal

diffuser plates

1818

1818 1010

1818 1010

55

1818 1010

55 3000km3000km 1000km1000km

1818 1010

55 3000km3000km 1000km1000km

Scan Profile….

• Successive W-E and E-W strip has 5%

overlap

• N-S step size is dictated by band having

minimum swath

• Scan rate can be programmed to any value

between 0.004/s to 0.4/s• Imaging operations will not be carried

out for two hours around midnight

Coverage area

(km2)Bands Scan rate (/s) Time (min.)

6000 6000 MX-LWIR 0.4 17

3000 3000 MX-LWIR 0.4 7

3000 3000MX-VNIR and MX-

LWIR0.012 84

1000 1000MX-VNIR and MX-

LWIR0.012 13

1000 3000 All four 0.01 119

1000 1000 All four 0.004 94

Scan Time & Performance

Bands SWR (%) SNR

MX-VNIR 10 200

HyS-VNIR 40 400

HyS-SWIR 20 400

MX-LWIR 20500 mK NEdT for

300K target

BandChannels

(µm)

Spatial

sampling

(meter)

Swath (km)

MX-VNIR

0.45 - 0.52

0.52 - 0.59

0.62 - 0.68

0.71 - 0.74

0.77 - 0.86

0.845 - 0.875

50 490

HyS-VNIR0.4 - 0.87

~ 5 nm500 160

HyS-SWIR0.9 - 2.5

~ 7 nm500 190

MX-LWIR

7.1 - 7.6

8.3 - 8.7

9.4 - 9.8

10.3 - 11.3

11.5 - 12.5

13.0 - 13.5

1500 370

EW

S

N

S

W

A

T

H

SPATIAL

SAMPLE

SCAN

East-west separation between extreme focal

planes is about 1000 km Scale is only indicative

SCAN

High resolution Mx and Hyper-spectral on one platform.

Wide spectral range: VNIR to LWIR (0.4 to 13.5µM)

Different scan rates for different bands for optimizing scan time and SNR

All spectral bands / channels chosen after extensive discussions with the user teams at SAC

Several iterations on Payload and Spacecraft for optimized configuration Typical operation sequence generated based upon user

feedback

Keep Out Time (KOT) of ±2hrs local midnight for thermal management.

Reception at multiple stations is considered as a part of the system design

Payload components / subsystems are at advanced stage of procurement

Application Coverage Area RepeativityPreferable Time for

Acquisition

Weather forecasting 1010 3 30 min ~ 17 minutes

Nowcasting 55 10 min ~ 7 minutes

Vegetation 55 Daily 1 hour

Theme specific1.55 &

1.51.5As per request Within sunshine

Modes Field-of-Regard Operational Consideration

Sub-continent scan 1010• Nominally MX-LWIR only planned for this mode

(weather-forecasting)

Indian landmass /peninsula

55• MX-LWIR planned on routine basis at every ½

hour interval (now-casting)• MX-VNIR planned during 9AM to 4PM SLT

User defined1.55

1.51.5• On request basis, including MX and HySI

Full globe scan 1818• Not a nominal operating mode• In case required, this will be covered using four

1010 quartets

Cameras Operating Modes

Coverage Area BandsScan Rate(/s)

Time *min.)

Reason for choosing ScanRate

1010(~6000Km x6000Km)

MX-LWIR 0.4 (Max) 17Optimum operating rate forMX-LWIR

55(~3000Km x3000Km)

MX-LWIR 0.4 7Optimum operating rate forMX-LWIR

55(~3000Km x3000Km)

MX-VNIRand MX-LWIR

0.012 84 Fast Coverage

55(~3000Km x3000Km)

All four 0.01 242Max. operating rate for HyS-VNIR

1.55(~1000Km x3000Km)

All four 0.01 119Max. operating rate for HyS-VNIR

1.51.5(~1000Km x1000Km)

All four 0.004 ( Min) 94 Good SNR

* Includes 5% overlap between successive E-W line

Excludes spacecraft turn around time

Swath in various Operating Modes

Scan Direction E/W

Nth E/W Scan

( N/S step = 160

KM)

(N+ 1)th E/W Scan

HyS-

VNIRHyS-

SWIR495

KM

190 KM160 KM 475 KM

Data corresponding to Lowest Swath Detector will be

transmitted : In above example HyS-VNIR has lowest swath,

so data of of 160 km swath for all channels ( with approx. 5%

overlap in sucessive scan will be transmitted)

3.5°

On-orbit : Solar panel Power generation is reduced due to

± 3.5° inclined orbit operations0.5 hours non-rotation of SADA9° panel offset due to Payload operations

9°

Down link freq. band (Ku-Band) 12.25 – 12.45 GHz

Orbital slot 93.5 ˚ East

Information Data rate 228 Mbps

Modulation QPSK (FEC 7/8)

Required EIRP 45 dBW

Link BER 1 * 10-8 @ 7 dB Eb/No

GND. Station antenna dia. 11m (G/T : 36 dB/ K)

GND. Station location Hyderabad, Ahmedabad, New Delhi

For both 0 deg & 180 deg YAW Flipping,

(Communication link 36db/K G/T considered for

ground station.)

Electronic Steered Antenna

Phased Array Antenna having 8 8 radiating elements.

Linear vertical Polarizatiosn

Cross Polarization Isolation : 28dB

Data Tx. Major Spec.….…

Parameters For GS

Antenna

11m

Path Loss 205.98 dB

Rain Attenuation 6 dB

Antenna pointing loss 1.5 dB

Implementation Margin 2 dB

Downlink Eb/No (G/T) 11.4 dB

Required Eb/No (G/T) 7 dB

Margin 4.4 dB

Link Budget

Irrespective of camera pointing on Earth

globe, the Antenna beam pointing is

always at the same location

Electronically steerable Antenna (PAA)

High Data rate transmission in Ku band (~228Mbps)

Imaging area (camera pointing)

Antenna beam pointing

Phased Array Antenna (PAA)…

BEAM SCANNING OVER

GLOBAL COVERAGE

Conventional C-band TTC-RF system TTC Frequencies:

TM: 4186.848MHz / 4189.344MHzTC : 6415.000MHz / 6421.480MHz

Orbital slot is 93.5oE• Co-located with INSAT-3A, INSAT-4B & GSAT-15

Receivers are ON continuously (Hot redundancy)

Tele-commanding through Omni antenna

Telemetry available through- High power mode through Omni Antenna- Low power mode through Medium Gain Antenna

(beam width 25 )- Payload link

Subsystem MASS (in kg.)

Optics + Electronics Payload Segment 215.0* Communication Payload Segment 83.0 Structure (includes 5 kg of passive isolator for wheel) 145.0Mechanisms (including yoke) 13.9Thermal Control System 65.0Propulsion System 131.0TTC-RF 15.7Attitude Orbital Control System & OBC 52.6Sensors 12.0Inertial System 66.0Power System 97.6 Integration 70.0Implementation Margin 10.2 Spacecraft Dry Mass 977.0 Propellant 1119.5 Pressurant 3.5Spacecraft Lift-Off Mass 2100.0

Subsystems/ Parameters GTO On Orbit

SS Eqn. Eclipse

Payload 0 640 640 640

Main Frame 182 532 533 341

Thermal 250 250 250 150

Battery Charging 40 0 150 0

One String Margin 0 94 102 0

Total Requirements 472 1516 1675 1131

Power Generation (nominal) 2200 1910 2105 1400

Power Generation for following Conditions:

(9 deg panel offset due to payload operations

+ 3.5 deg inclined orbit operations

+ 0.5 hour non-rotation of SADA)

NA 1626 2037 NA

Available Margin 1728 110 362 269

Subsystems GTO On Orbit

SS Eqn. Eclipse

Power Electronics 15 20 20 20

TTC-Tx 44 28 28 28

TTC-Rx 20 20 20 20

OBC 48.6 66 66 66

Magnetic Torquer 0 27 27 27

RLG (ILG-300)(*)/ FOG 35 35 35 35

5 RWs +WDE (0.3NM,15NMS) 0 290 290 100

SADA 0 16 16 16

Star Sensor (Mark -3; 2 APU+3-CHU) 14 14 14 14

Integration loss 5 16 17 15

Total 181.6 532 533 341

SUMMARY OF THE PROPELLANT BUDGET

Attitude Hold + EW SK : 70 m/s

Station Acquisition : 10 m/s

Repositioning & De-orbiting : 20 m/s

Launcher Dispersion Margin : 100 m/s

Additional Delta-V Margin : 280m/s

No NSSK is planned, but margin exists so if required itcan be planned.

GISAT-2 will be repeat of GISAT-1.

for your kind attention !