Page 1ASAR Validation Review - ESRIN – 11-12 December 2002
IM and WS Mode Level 1 Product quality
updateIntroductionIM Mode OptimisationUpdated IMS product quality (VV & HH)Updated IMP product quality (VV & HH)Updated IMM product quality (VV & HH)Updated WSM product quality (VV & HH)Conclusions
B. RosichESA/ESRIN
Page 2ASAR Validation Review - ESRIN – 11-12 December 2002
IM Mode products characterised and preliminary calibrated at the ECR (September) for VV polarisation.
IM Mode optimisation peformed in October requires a revision of the product quality. Characterisation of HH polarisation also needed.
Very prelimianry verification of WSM products at the ECR for VV polsarisation. An additional change in the mode requires revision of product quality. Characterisation of HH polarisation also needed.
Introduction
Page 3ASAR Validation Review - ESRIN – 11-12 December 2002
IM Mode Optimisation
IM mode optimisation at instrument level- Increase the Tx. Chirp BW to 16 MHz for all swaths (17-10-02):
IM mode optimisation at processing level- Depends on product type
old BW [MHz] new BW [MHz]SS1 16 16SS2 16 16SS3 12.67 16SS4 10.79 16SS5 9.53 16SS6 8.84 16SS7 8.21 16
Page 4ASAR Validation Review - ESRIN – 11-12 December 2002
ASAR IMS Product charateristics
Slant range, single look complex image.
Single polarisation VV or HH. Multiple incidence angles (IS1 to IS7). Coverage from 100 Km to 56 km
Natural pixel spacing in range and azimuth. Azimuth resolution from 4 m to 5 m. Range resolution from 9 m to 18 m due to decreasing chirp bandwidth.
Elevation antenna pattern correction not applied. Range spreading loss correction not applied.
Hamming window with a=0.75 applied in azimuth and range
Processing algorithm: Range Doppler. Phase preserving.
1751, IS1
Page 5ASAR Validation Review - ESRIN – 11-12 December 2002
Change of processing settings & products characteristics for IMS
productsRange Processing: Full BW processed for all beams. Constant slant
range resolution from IS1 to IS7.
IMS slant range res. VV
8101214161820
1 2 3 4 5 6 7 8 9 10 11 12 13
m
IS1
IS2
IS3
IS4
IS5
IS6
IS7
IMS Slant range res. New BW. VV & HH
8.5
9
9.5
10
10.5
1 3 5 7 9 11 13 15
m
IS1...IS7
Change in quality requirements for IMS products.
Page 6ASAR Validation Review - ESRIN – 11-12 December 2002
Azimuth processing: No changes.
Gain settings: No changes. Complete Tx. BW used before/after the BW change. No changes in the processor gain. Same K as for data acquired before the BW change.
IMS Rel RCS (K=45.6 dB). New BW
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
0 2 4 6 8 10 12
dB new BW VV
new BW HH
IMS Absolute Calibration update
Page 7ASAR Validation Review - ESRIN – 11-12 December 2002
PF-
ASAR
version 3.01 & 3.02 3.03 3.01 & 3.02 3.03
IMS
OK
(Nominal quality)
OK
(Nominal quality)
OK
(Higher Rg.res)
OK
(Higher Rg.res)
Data Acquired After 17- Oct. 2002Data Acquired Between 5- Sept. & 17- Oct. 2002
IMS Product quality vs. time &
vs. PF-ASAR version
Page 8ASAR Validation Review - ESRIN – 11-12 December 2002
Visible az. Ambigities for HH products
- Distributed target ambig. ratio: -25.5 dB (IS5), -24 (IS4)
Point target ambiguity ratio: ~-26 dB
IMS HH Ambiguities
Ambiguity ratio requirement is –25 dB. Migth be too high for HH products over low backscattering areas.
Page 9ASAR Validation Review - ESRIN – 11-12 December 2002
Properties of IMP Products• Ground range detected imagery• Single polarisation (VV or HH)• Elevation antenna pattern and range
spreading loss corrections applied• Size of up to 150Mbytes with 2 byte
(16bit) amplitude pixel values• Swath widths of 100 km (IS1) to 56 km
(IS7) with azimuth extents of ~100 km• Azimuth resolution of 20.7m (4 looks of
320 Hz)• Range resolution from 21m (IS2 far
range) to 37m (IS1 near range) and ~26m for IS3 to IS7
• 12.5m by 12.5m pixels
Page 10ASAR Validation Review - ESRIN – 11-12 December 2002
Change of processing settings & product characteristics for IMP products
Range Processing: - Range look BW: same as before, i.e. same range resolution- Number of range looks: same as before (1). Increase in noise level
expected for the higher inc. ang. beams.
Azimuth processing:- No changes. Same number of looks (4) and same look BW.
Gain settings: - Gain adjusted to compensate the fact that the full Tx. BW is only
partially processed.- Same K as for data acquired before the BW change.
Page 11ASAR Validation Review - ESRIN – 11-12 December 2002
Rg.Res. - IMP new Tx.Chirp BW, VV & HH
20222426283032343638
14 19 24 29 34 39 44inc.angle [deg[
rg.r
es.
[m
]
IS1
IS4
IS5
IS6
IS7
IS1 theor.
IS4 theor.
IS5 theor.
IS6 theor.
IS7 theor.
IMP Range resolutionMeasurements demonstrate that there is no change in range resolution and values are well within the requirements for VV & HH
Page 12ASAR Validation Review - ESRIN – 11-12 December 2002
K - IMP new BW VV & HH
54.6
54.8
55
55.2
55.4
55.6
55.8
56
56.2
0 1 2 3 4 5 6No. of measurements
K [
dB]
IS1 VV
IS4 HH
IS5 HH
IS5 VV
IS6 VV
IS7 VV
Mean K 55.3 dBK standard dev. 0.33 dB
IMP Absolute CalibrationMeasurements demonstrate that the same absolute calibration factor applies for data acquired before and after the BW change.
Mean K 55.3 dBK stdandard dev. 0.31 dB
Page 13ASAR Validation Review - ESRIN – 11-12 December 2002
Az. Res. IMP VV & HH
21
21.5
22
22.5
23
0 5 10 15 20No.of measurements
az.
res.
[m
]
ISLR IMP VV & HH
-15
-14
-13
-12
-11
-10
0 5 10 15 20No. of measurements
ISL
R [
dB
]
PSLR IMP VV & HH
-20
-18
-16
-14
-12
0 5 10 15 20No. of measurements
PS
LR
[d
B]
IMP Azimuth resolution, ISLR, PSLR
- Values are within the requirements- High PSLR observed however in few cases
Page 14ASAR Validation Review - ESRIN – 11-12 December 2002
IMP Product quality vs. time &
vs. PF-ASAR version
PF-
ASAR
version 3.01 & 3.02 3.03 3.01 & 3.02 3.03
IMP/ IMG
OK
(Nominal quality)
Degraded Rg. Res.
but acceptable quality (IS3
to IS7)
Higher Rg. Res.
(for IS3 to IS7,
e.g.13.3 m for IS7!!)
OK
(Nominal quality)
Data Acquired Between 5- Sept. & 17- Oct. 2002 Data Acquired After 17- Oct. 2002
Page 15ASAR Validation Review - ESRIN – 11-12 December 2002
3354, IS5, 2 looks3354, IS5, 4 looksClear Az. Ambiguities on HH products, over low backscattering areas. Amb.ratio: -25.8 (IS5) -21.1 (IS4)
Processing only 2 looks in az.: Amb.ratio: -28 dB (IS5)
IMP HH Az. Ambiguities
Page 16ASAR Validation Review - ESRIN – 11-12 December 2002
IMM Product Characteristics• Ground range projected detected products• Nominal resolution < 150 m . Pixel spacing 75 m• 8 looks in azimuth, 4 looks in range. ENL > 30• Antenna pattern and range spreading loss correction applied• Data output as unsigned 16 bit• Systematic stripline processing: products as long as the complete
acquisition segment• Innovative ground range projection to keep constant incidence angle
at the center of the product (common to all stripline products)
Page 17ASAR Validation Review - ESRIN – 11-12 December 2002
Range Processing: - Range look BW: same as before, i.e. same range resolution- Number of range looks: 10 (5 before). ENL increase expected.- Look overlap different for different beams. Different ENL
expected.
Change of processing settings & products characteristics for IMM products
Swath rg.look BW [MHz] tot.orig.BW [MHz] tot. BW [MHz] % Overlap (10 looks)IS1 3.63 16 16 62IS2 3.02 16 16 52IS3 2.43 12.67 16 38IS4 2.11 10.79 16 27IS5 1.92 9.53 16 19IS6 1.78 8.84 16 11IS7 1.69 8.21 16 6
Azimuth processing:- No changes. Same number of looks (8) and same look BW.
Page 18ASAR Validation Review - ESRIN – 11-12 December 2002
BEAM
ENL before Chirp BW
change
ENL after Chirp BW
change
IS1 27 35IS2 30 NAIS3 28 NAIS4 31 70IS5 32 70IS6 34 NAIS7 27 80
IMM ENL• Measurements not available yet for all
swaths.
• No changes expected for IS1 and IS2.
•For the beams with very small look overlap, values up to 80 looks are achieved
• Initial requirement for IMM ENL was 30 looks.
• Only negative impact is throughputChange in quality requirements needed.
Page 19ASAR Validation Review - ESRIN – 11-12 December 2002
IMM new BW rg.res. VV & HH
120.000
130.000
140.000
150.000
160.000
170.000
15.00 20.00 25.00 30.00 35.00 40.00 45.00
inc.angle [deg]
reso
luti
on
[m
]
IS1 th.
IS4 th.
IS5 th.
IS6 th.
IS7 th
IS1
IS4
IS5
IS6
IS7
Range & Azimuth Resolution match expected theoretical values for all beams
Theoretical values ranging from 107 m (far range IS1) to 160 m (near range IS1)
IMM Spatial Resolution
IMM new Chirp BW, Az. res. , VV & HH
140
142
144
146
148
150
152
0 1 2 3 4 5
No of measurementsa
z.re
s. [
m] IS1
IS4
IS5
IS6
IS7
Theor.res.
c
Page 20ASAR Validation Review - ESRIN – 11-12 December 2002
K - IMM orig. BW, VV
66
68
70
72
74
76
0 5 10 15No of Measurements
dB
IS1
IS2
IS3
IS4
IS5
IS6
IS7
Mean K [dB] 70.22K standard dev.[dB] 0.33
K - IMM new BW, VV & HH
66
67
68
69
70
71
0 1 2 3 4
No of measurements
dB
IS1
IS4
IS5
IS6
IS7
Mean K [dB] 67.5K standard dev [dB] 0.56
Change of K between products with original Tx. Chirp BW and products with new full TX. Chirp BW.
IMM Absolute calibrationNo changes in processing gain. Changes in product level expected between data acquired before/after the BW change.
Page 21ASAR Validation Review - ESRIN – 11-12 December 2002
PF-
ASAR
version 3.01 & 3.02 3.03 3.01 & 3.02 3.03
IMM
OK
(Nominal quality)
OK
(Nominal quality)
OK
(Nominal quality, dif.K)
OK
(Higher ENL, dif.K)
Data Acquired Between 5- Sept. & 17- Oct. 2002 Data Acquired After 17- Oct. 2002
IMM Product quality vs. time &
vs. PF-ASAR version
Page 22ASAR Validation Review - ESRIN – 11-12 December 2002
Visible Az. Ambiguities for HH products:
• Distributed target ambig. ratio: ~-20 dB
3354 ,IS5, HH 3397,IS4, HH
IMM HH Az. Ambiguities
3354 ,IS5, HH, 4 looks
IMM reprocessing using 4 rather than 8 looks in azimuth:
• Amb. Ratio: - 24.5 dB
Page 23ASAR Validation Review - ESRIN – 11-12 December 2002
WSM Product characteristics
• Ground range projected detected products
• Nominal resolution < 150 m
• Swath width: 406 Km
• Pixel spacing 75 m
• ENL > 12 for all the different subswaths
• Antenna pattern and range spreading loss correction applied
• Data output as unsigned 16 bit
• Systematic stripline processing: products as long as the complete acquisition segment
Page 24ASAR Validation Review - ESRIN – 11-12 December 2002
Initial instrument settings (till 13-08-02) Tx.Chirp BW:
Mode timeline (pulses per burst): SS1-SS5: 50, 80, 67, 87, 74
Initial processing/product settings (version < 3.01): Rg. Look BW:
Number of range looks: 3
•Result: - Range resolution ~ 150 m and Azimimuth resolution ~90 m
- ENL: below the requirements (12) -> from 8 for SS1 to 6 for SS5
SS1 SS2 SS3 SS4 SS5range look BW [MHz] 2.66 2.05 1.77 1.61 1.5
SS1 SS2 SS3 SS4 SS5Original BW [MHz] 7.15 5.33 4.39 3.01 2.82
WSM Initial product quality
Page 25ASAR Validation Review - ESRIN – 11-12 December 2002
First mode optimisation at instrument level (13-08-02): IncreaseTx.Chirp BW:
SS1 SS2 SS3 SS4 SS514.75 12.86 10.48 9.54 8.78(x2) (x2.4) (x2.4) (x3) (x3)
New BW [MHz]
First WSM optimisation (I)
SS1 SS2 SS3 SS4 SS5range look BW [MHz] 2.66 2.05 1.77 1.61 1.5
New processing/product settings (version >= 3.01):Rg. Look BW:
Number of range looks: 7
Page 26ASAR Validation Review - ESRIN – 11-12 December 2002
Result:• Range resolution: ~ 120 m
• Azimimuth resolution: ~90 m -> High undersampling & not-square resolution
• ENL: higher than initial spec (12)
•Inter-burst ambiguities (~-21 dB) detected in high contrast scenes (already present before the BW change)
SS1 15.3SS2 15.8SS3 16.2SS4 16.1SS5 16.5
First WSM optimisation (II)
Page 27ASAR Validation Review - ESRIN – 11-12 December 2002
WSM 2703
Second WS mode optimisation at instrument level (30-10-02)Change of mode timeline (expect SS1):
SS1-SS5: 50, 65, 55, 71, 60
New processing settings: None. Only AUX data updated
Second WSM optimisation
Result: Removal of inter-burst ambiguities Increase of Az. Res.
Page 28ASAR Validation Review - ESRIN – 11-12 December 2002
WSM rg.resolution VV & HH
90
100
110
120
130
140
150
14 24 34 44
inc. anglr [deg]
rg.
res.
[m
]
SS1
SS2
SS3
SS4
SS5
WSM Az. res. VV & HH
80
90
100
110
120
3100 3300 3500 3700 3900
orbit number
az
. re
s. [
m]
Az. Res
Az.res (orig.)
WSM Final products resolution
• Nominal products are still undersampled: 1.2 in range, 1.4 in azimuth.• Resolution is almost square. Could be adjusted to be more similar in both directions.• IRF measurements performed on oversampled products of 40x40 m.
Page 29ASAR Validation Review - ESRIN – 11-12 December 2002
K: WSM final settings (VV & HH)
67
67.5
68
68.5
69
69.5
70
3100 3300 3500 3700 3900orbit
K [d
B]
K (HH)
K (VV)
HH VV AllMean K [dB] 68.85 68.95 68.88K Std.dev. [dB] 0.59 0.33 0.50
K (VV) from rain forest: 69.08 dB
WSM Absolute calibration update
Page 30ASAR Validation Review - ESRIN – 11-12 December 2002
Noise level for SS1 expected to be higher than for the other swaths.
Measured values for final settings: SS1: ~-22 dBSS2-SS5: ~-24,-25 dB
The difference in noise level between SS1 and SS2 is clearly visible in the images.
SS1 SS2
WSM Noise Equivalent 0
Page 31ASAR Validation Review - ESRIN – 11-12 December 2002
IM mode BW increase has resulted in an improved IMS and IMM product quality and will increase the IM InSAR performance. Products quality shall be now stable.
The BW increase shall be almost transparent for IMP products. Quality could be improved with multi-look in range.
WSM optimizations provide very good product quality. Products should be now stable.
Quality results for HH polarisation are equivalent to those for VV polarisation.
Conclusions