nrsc risat 1 data format 2.pdf

Feb 2013 RISAT-1 Data Processing NRSC User Interaction Meet SIPA/SAC

RISAT-1 Data Processingby

Santanu [email protected]


Beam Mode

Level of

Processing

Look Angle(Deg)

NominalScene size

Azimuth* Range (km)

Azimuth/ RangeNo of Looks

Azimuth/ Range

Resolution(m)

(with weighting)

Azimuth/Range

Sampling(m)

FRS1

L1SLC 11-49 25*25 1/1 3.3/2.2 2.3/1.8

L1GR11-24 25*25 4/2 13/22 – 10.6 9.2/9

24-49 25*25 4/2 13/10.3 – 5.6 4.6/4.5

L211-24 25*25 4/2 13/22 – 10.6 9.2/9

24-49 25*25 4/2 13/10.3 – 5.6 4.6/4.5

FRS2 L1SLC 11-49 25*25 1/1 10/4.68 4.6/3.6

MRS

L1SLC 11-49 115*115 1/1 23-25/8.8 14.2/7.2

L1GR11-22 115*115 1/1 24/45-22 13.8/1823-49 115*115 1/2 24/43-22 13.8/18

L211-22 115*115 1/1 24/45-22 18/1823-49 115*115 1/2 24/43-22 18/18

CRS

L1GR11-34 223*223 1/3 48/135-46 27.6/3634-49 223*223 1/4 48/60-45 27.6/36

L211-34 223*223 1/3 48/135-46 36/3634-49 223*223 1/4 48/60-45 36/36

RISAT-1 PRODUCT SPECIFICATIONS

Parameter Accuracy

Geo location

accuracy (RMSE)

750 m

(For plain areas)

Geometric Distortion

Meters FRS1 - 100 MRS - 150CRS - 300

Radiometric

Resolution (SLC)3.1 dB

PSLR -17 dB


RISAT-1 Data Processing Work Flow

Near Real Time Processing for FRS-1, FRS-2, MRS and CRS mode data


Imaging Mode

RAW

(CEOS)

L1-SLC

(CEOS)

L1-Ground Range

(CEOS)

L2-Geo Referenced

(CEOS & GeoTIFF)

(Proj: UTM & Polyconic)FRS-1 Available Available Available AvailableFRS-2 Available Available Not Applicable Not ApplicableMRS Available Available Available AvailableCRS Available Under

EvaluationAvailable Available

SAN,metadata

server

DP Scheduler System 8 core, 4 GB RAM, 2.83 GHz

SWITCH

4Gbps each

Level-0 SystemOpteron 8356 series

4-CPU 8-Core Server, 32 GB RAM, 2.66 GHz, (Xeon x7460 based)

6X Image Formation

RISATCluster

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

Tim

e in

sec

onds

1 2 4 8 16

RISAT-1 Data Processing System Architecture in IMGEOS

MODE SCENE ACQUISITION TIME

SCENE PROCESSING

TIME(Raw data to L2 GeoTiff )

FRS-1 ( 30 km)

4.6 sec 15

FRS-2 (30 Km)

4.6 sec 45

MRS(115 Km)

17.5 sec 55

CRS (230 Km)

32.8 sec 120

Data Processing Time in IMGEOS

Data Products Availability for various modes

PolarisationHH, HV, VV, VH, RV,RH

Product LevelsLevel-0 RAW Level-1 SLCLevel-1 Ground

RangeLevel-2 Terrain

Geocoded

RISAT-1 Data Processing


Range variation of Different Targets

698092698093698094698095698096698097698098698099698100

0 1000 2000 3000 4000 5000

azm sample

rang

e (m

) nr_azmmid_azmfar_azm

Stripmap Mode SAR

t-a/2

ta/2

Tnr

Tmid

Tfar

t0

RtR0

Targets at different

Azimuth positions

Frequency Characterictic of Different Targets

-1500

-1000

-500

0

500

1000

1500

0 1000 2000 3000 4000 5000

azm sample

freq

uenc

y (H

z)

nr_azmmid_azmfar_azm

Characteristic of Range Migration

01234567

-1500 -1000 -500 0 500 1000 1500

frequency (Hz)

del_

rng nr_azm

mid_azmfar_azm

Targets with identical range minimum have the same frequency modulation rates. Targets follow a common trajectory in

frequency domain

Frequency characteristics

-1500

-1000

-500

0

500

1000

1500

0 1000 2000 3000 4000

azm sample

freq

uenc

y (H

z)

nr_rngfar_rng

Tnr

Tmid Tfar

Targets at different Range positions have different frequency modulation rates and

do not follow the same trajectory in frequency domain

Targets at different Range positions


Stripmap Mode SAR

49505152535455

0 1000 2000 3000 4000

Azimuth Samples

Ran

ge S

ampl

es

Quad rcmlinear Interpol.FFT interpol.

2D Echo Signal Range Compression

Fully Focused

Range Cell Migration Correction

Range Compression – Cross-correlate data with replica in the range direction

Azimuth Compression - Construct a chirp with a required fm rate & Cross-correlate the RCM corrected signal with the chirp

C hirp S ignal

-1

-0.5

0

0.5

1

1778 1978 2178 2378 2578 2778 2978

sa m ple

Rea

l pt

Replica Signal Matched Filtering

Response Signal

-100

0

100

200

300

400

500

600

700

800

1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050

sample

Am

plitu

de

Pulse Compression


Stripmap Mode SAR Processing

f

compress detect & addcompress

Single look Multi look

SAR Raw Echo Data Range Compression

Single Look Image Multi Look ImageOne of four Looks


FRS1 Stripmap mode Images


ScanSAR Mode SAR

Azimuth 1

23

4

7

Ran

ge

sw6sw5sw4sw3sw2sw1

45

6

Azimuth

Ran

ge

beam0 Signal Processed

burst k

burst k+1

burst k+2

Processing of one ScanSAR beam

BlendedBursts

ScallopCorrected

Radiometric Corr.


ScanSAR Mode SAR

bm0 bm1 bm2 bm3 bm4 bm5Signal Processed ScanSAR beams

Mosaiced ScanSAR Ground Range dataCorrected ScanSAR beams

bm0 bm1 bm2 bm3 bm4 bm5

Azimuth Variations Range Variations Terrain Geo-coded Product


RIS

ATR

adar

sat-2

MysoreHomalinWest Homalin

MRS ScanSAR Images


Azimuth BWFilter 1Filter 2Filter 3Filter 4

Range

Azi

mut

h

VV VH HV HH

Alternate Polarization Mode SAR

HH/HV

VV/VHHH/HV

Burst Signal

C h i r p o f S t r ip m a p m o d e

- 1 .5

- 1

- 0 .5

0

0 . 5

1

1 . 5

0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0 2 5 0 0 3 0 0 0

s a m p le

real

par

t

R es p o n se o f S tr i p m a p m o d e

-1 0 0

-9 0

-8 0

-7 0

-6 0

-5 0

-4 0

-3 0

-2 0

-1 0

033 00 3 31 0 3 32 0 33 30 3 34 0 3 35 0 33 60 3 37 0 3 3 80 33 9 0 3 40 0

S a m p le

Am

plitu

de (d

B)

Compression of Continuous Signal C h i r p o f B u r s t m o d e

- 1 - 0 . 8 - 0 . 6 - 0 . 4 - 0 . 2

0 0 .2 0 .4 0 .6 0 .8

1

0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0 2 5 0 0 3 0 0 0

S a m p l e

R ea l p ar t

R e s p o n s e o f B u r s t m o d e

- 4 0

- 3 5

- 3 0

- 2 5

- 2 0

- 1 5

- 1 0

- 5

03 3 0 0 3 3 1 0 3 3 2 0 3 3 3 0 3 3 4 0 3 3 5 0 3 3 6 0 3 3 7 0 3 3 8 0 3 3 9 0 3 4 0 0

S a m p l e

Am

plitu

de (d

B)

Compression of Burst SignalSignal Memory

Filter 1 o/p

Filter 2 o/p

Filter 3 o/p

Filter 4 o/p Stitched o/p


FRS-2 Image Hirakund FRS-1 RV + RH Image Ahmedabad

RISAT Polarimetric Images


SAR Geolocation Algorithm

Attitude

λ,фOptical P/L

Geolocation Algorithm

Ellipsoid/DEM

InputScan,Pix

Orbit

SAR Geolocation

Algorithm

Doppler Centroid Orbit

InputScan,

PixEllipsoid/DEMInitial

GuessScan, Pix

Range

λ,ф

Azimuth

Beam Center

SAR

A

D

B

C

Range

A

C

B

D

Zero Doppler Processing

Range

Azimuth

D C

B A

SAR signal space

SAR image space

Iso-Range Contours

Iso-Doppler Contours

ispjmr r

.0

Range Equation :

isp

ispispjifDC

.2,

Doppler Equation :


Use of DEM for Antenna Pattern Correction & Geo-location Improvement

Swath Selection in Product & Radiometric Correction using antenna Pattern & DEM

Geo-location Improvement using DEM

Without Antenna Pattern Correction With Ant Pat Corr. and no DEM With Ant Pat Corr. and DEMApplication of DEM ensures appropriate swath selection and correct radiometric correction

L1 Gnd Rng ImageLoc Acc < 300 m

DEM FieldEllipsoidal Ht : 3 to 5 Km L2 Terrain Geocoded Image

with true height Loc Accuracy < 300 m

L2 Terrain Geocoded Image with average height Loc

Accuracy < 1.5 Km

Distortion due to foreshortening &

Layover

No Distortion


MRS – India Mosaic

Development of Software for INDIA Mosaic : 100 m sampling 1. Registration 2. Radiometric Balance

Future Product Operationalization – Speckle Reduced Products / Polarimetric Products / Mosaic Products / Multi-Temporal Registered Products / Optical-SAR Fused Products

HH Pol HV Pol


Analysis of Point Target Response

SAC/Ahmedabad NalSarovar

ShadnagarNarkhodaCorner Reflectors have been deployed and FRS-1 SLC images have been evaluated for geometric resolution 3m ( wt 0.9 ) / 3.25 m ( wt 0.7) in azimuth & 2.0 m ( wt 0.7) in range with adequate PSLR & ISLR


Payload Characteristics

Platform Characteristics :

Payload & Platform Characteristics

Health of Raw Echo Data is excellent

-120.00

-100.00

-80.00

-60.00

-40.00

-20.00

0.000 10 20 30 40

FDC

Val

ue (I

n H

z)

Scene Number

FDC Vs Scene No (Dumping Orbit-326 Polarization-RV)

Azimuth

T

beam centre

closest

approach

tant_peak

tzero_dopp

Excellent Yaw Steering Resulting in low Doppler Centroid Estimates

DQE Package is installed at NRSC1. Geometric DQE Package2. Radiometric DQE Package3. Raw Data Analysis Package4. Point Target Analysis Package5. Onboard Calibration Package

DQE Operational Package


VV

VH

RV

RH

Radiometric Accuracy

Amazon Statistics HH : -6.47 ± 0.71 dB VV : -6.11 ± 0.23 dB1. Estimation of Distribution of Sigma Naught2. Evaluation of Radiometric Correction Procedure3. Estimation of Minimum Sigma Naught Parameter

Radarsat-1 : Absolute Radiometric Accuracy : 3 dBRadarsat-2 : Absolute Radiometric Accuracy : 1 dBRISAT-1 : Relative Radiometric Accuracy : 1 dBRISAT-2 : Absolute Radiomeric Accuracy : 2 dB

HH

HV


RISAT Data Extraction & Display Package

RISAT Data Extraction Package in Linux & Windows

Image Display & Display of Meta Data & Auxiliary Files


THANK YOU

nrsc risat 1 data format 2.pdf

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