![La georeferenziazione delle informazioni territoriali ...lps16.esa.int/posterfiles/paper1213/[RD9]_Georeferenziazione.pdf · utilizzazione anche da parte di chi non abbia approfondite](https://static.fdocuments.net/doc/165x107/5c69850c09d3f2f5638d4f59/la-georeferenziazione-delle-informazioni-territoriali-lps16esaintposterfilespaper1213rd9.jpg)
Lps16 scagliola interf_cal
15
CryoSat Interferometer Performance after 5 years in Orbit Michele Scagliola, Aresys Marco Fornari, ESA Jerome Bouffard, ESA
-
Upload
michelescagliola -
Category
Engineering
-
view
70 -
download
3
Transcript of Lps16 scagliola interf_cal
CryoSat Interferometer Performance after 5 years in Orbit
Michele Scagliola, Aresys
Marco Fornari, ESA
Jerome Bouffard, ESA
Outline
Calibration of the CryoSat interferometer
End-to-end performance and CryoSat requirement on across-track accuracy/precision
Improving the end-to-end performance of Cryosat Interferometer by on-ground processing
Conclusions
Calibration of CryoSat Interferometer
End-to-end calibration of CryoSat interferometer: in orbit calibration campaigns rolling left and right the spacecraft of about ±0.4 deg the purpose is to deternine the across-track slope of the ocean surface
First arrival
Right
antennaLeft
antenna
q
χ
P
Satellite velocity
vector
Boresight direction
)/())0(( 0 BkArg
Rh /1
the angle of the first arrival from SARin L1b
roll mispointing angle from Star Tracker
a geometric factor
Ocean surface slope
Calibration of CryoSat Interferometer
End-to-end calibration of CryoSat interferometer: in orbit calibration campaigns rolling left and right the spacecraft of about ±0.4 deg the purpose is to deternine the across-track slope of the ocean surface slope of ocean surface is known from geoid The error between the measured angle of arrival (AoA) and the expected AoA from geoid
First arrival
Right
antennaLeft
antenna
q
χ
P
Satellite velocity
vector
Boresight direction
geoid
m
error on the AoA coming from the SIRAL and the IPF1
error on roll coming from star tracker and on ground processing
Measured error
Calibration of CryoSat Interferometer
The end-to-end error on the AoA can be modeled as a linear function of the measured AoA, so that the interferometer calibration function results in -0.01 -0.005 0 0.005 0.01
-2.4
-2.3
-2.2
-2.1
-2
-1.9
-1.8
-1.7
-1.6
x 10-3
Measured AoR [rad]
Err
or
on
Ao
R [
rad
]
(q) = -0.025472 q -0.0019043
m
(q)
0)( a
phase departure [1] roll bias [1]
[1] Galin, N.; Wingham, D.J.; Cullen, R.; Fornari, M.; Smith, W.H.F.; Abdalla, S., "Calibration of the CryoSat-2 Interferometer and Measurement of Across-Track Ocean Slope," in Geoscience and Remote Sensing, IEEE Transactions on , vol.51, no.1, pp.57-72, Jan. 2013
By analysis of the data acquired during the roll calibration campaign, the interferometer calibration parameters are computed
Interferometer Calibration function
Err
or
on
AoA
[ra
d]
Measured AoA [rad]
3996.1)588.9()( ee
End-to-end performance and CryoSat requirements
The end-to-end performance of the CryoSat interferometer can be evaluated on the residual error on the measured AoA after that the calibration function has been applied
0 ammr
Residual error
r
rSTD
CryoSat System req. on interferometer
Value E2E performance figure Symbol
Residual across-track accuracy @2000km
141 μrad absolute average of the residual error on AoA
Residual across-track precision @1Hz
60 μrad standard deviation of the residual error on AoA
Calibration campaigns: BaselineC
Analysis of BaselineC CryoSat L1b SARin acquired during the roll campaigns
below the requirements highly dependent on the Star Tracker that
provides the roll mispointing information
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
50
100
150
Time [mm-yyyy]
Ab
s.
err
. [1
0- 6 r
ad
]
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
10
20
30
40
50
60
70
Time [mm-yyyy]
ST
D [
10
- 6 r
ad
]
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
50
100
150
Time [mm-yyyy]
Ab
s.
err
. [1
0- 6 r
ad
]
EECFI STR average
EECFI STR1
EECFI STR2
EECFI STR3
End-to-end requirement
Residual across-track accuracy Residual across-track precisions
below the requirements independent of the Star Tracker that
provides the roll mispointing information
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
50
100
150
Time [mm-yyyy]
Ab
s.
err
. [1
0- 6 r
ad
]
EECFI STR average
EECFI STR1
EECFI STR2
EECFI STR3
End-to-end requirement
Calibration campaigns: BaselineC
Analysis of BaselineC CryoSat L1b SARin acquired during the roll campaigns
below the requirements highly dependent on the Star Tracker that
provides the roll mispointing information
below the requirements independent of the Star Tracker that
provides the roll mispointing information comparable to Instrument noise at L1B
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
50
100
150
Time [mm-yyyy]
Ab
s.
err
. [1
0- 6 r
ad
]
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
10
20
30
40
50
60
70
Time [mm-yyyy]
ST
D [
10
- 6 r
ad
]
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
50
100
150
Time [mm-yyyy]
Ab
s.
err
. [1
0- 6 r
ad
]
EECFI STR average
EECFI STR1
EECFI STR2
EECFI STR3
End-to-end requirement
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
50
100
150
Time [mm-yyyy]
Ab
s.
err
. [1
0- 6 r
ad
]
EECFI STR average
EECFI STR1
EECFI STR2
EECFI STR3
End-to-end requirement
Residual across-track accuracy Residual across-track precisions
Instrument noise at L1b
Improving the end-to-end performance An activity was started aiming at verifying if the end-to-end performance in the sense of residual across-track accuracy can be still improved.
Following possible improvements have been identified
1. During on-ground processing of Star Tracker data, the aberration of the light can be (properly) corrected: accuracy of the mispointing angle is increased
2. A calibration function different for each Star Tracker can be computed and then applied to SARin L1b data
Calibration campaigns: aberration correction applied
Analysis of BaselineC CryoSat L1b SARin acquired during the roll campaigns
much below the requirements independent on the Star Tracker that
provides the roll mispointing information
No degradation applying aberration corr. independent of the Star Tracker that
provides the roll mispointing information
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
10
20
30
40
50
60
70
Time [mm-yyyy]
ST
D [
10
- 6 r
ad
]
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
50
100
150
Time [mm-yyyy]
Ab
s.
err
. [1
0- 6 r
ad
]
Residual across-track accuracy Residual across-track precisions
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
50
100
150
Time [mm-yyyy]
Ab
s.
err
. [1
0- 6 r
ad
]
EECFI STR average
EECFI STR1
EECFI STR2
EECFI STR3
End-to-end requirement
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
50
100
150
Time [mm-yyyy]
Ab
s.
err
. [1
0- 6 r
ad
]
EECFI STR average
EECFI STR1
EECFI STR2
EECFI STR3
End-to-end requirement
Calibration campaigns: aberration correction applied
Analysis of BaselineC CryoSat L1b SARin acquired during the roll campaigns
much below the requirements independent on the Star Tracker that
provides the roll mispointing information
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
50
100
150
Time [mm-yyyy]
Ab
s.
err
. [1
0- 6 r
ad
]
Residual across-track accuracy
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
50
100
150
Time [mm-yyyy]
Ab
s.
err
. [1
0- 6 r
ad
]
Aberration correction not applied
09-2010 04-2011 10-2011 05-2012 11-2012 06-2013 01-2014 07-2014 02-20150
50
100
150
Time [mm-yyyy]
Ab
s.
err
. [1
0- 6 r
ad
]
EECFI STR average
EECFI STR1
EECFI STR2
EECFI STR3
End-to-end requirement
End-to-end performance: operational acquisitions
The end-to-end performance evaluated on roll campaigns data
The end-to-end performance evaluated on operational BacelineC SARin L1b products
achievable end-to-end performance of CryoSat Interferometer Residual error minimized by computation of the Calibration Function
operational end-to-end performance of CryoSat Interferometer
The accuracy/precision of the SARin L1b that are made available to science users
End-to-end performance: operational acquisitions
End-to-end performance of CryoSat Interferometer from a dataset of more than 200 BaselineC SARin L1b products: all SARin L1b products acquired over a SARin patch in Indian ocean, that has been active in operations from Nov. 2010 to May 2012 (about 17 months)
Definition E2E Accuracy on AoA [rad]
E2E Precision on AoA [rad]
Contribution to height error [mm]
End-to-end requirement 141 60 14.6
BaselineC SARin L1B 105 32 6.8
Aberration correction applied 57 32 2.9
Aberration correction applied Roll bias function of Star Tracker 21 32 1.0
End-to-end performance: transponder acquisitions
The improvement in the sense of interferometer performance given by the application of the aberration correction and by using a roll bias different for each Star Tracker has been verified also by analysis of acquisitions over Transponder
Paper 303 - Session title: Cryosphere Posters
CRYO-6 - CryoSat-2, SIRAL Calibration with Transponder
Garcia-Mondejar, Albert (1); Fornari, Marco (2); Mertikas, Stelios (3); Bouffard, Jerome (4); Roca, Mònica (1) 1: isardSAT Ltd.; 2: ESTEC, ESA; 3: Technical University of Crete; 4: ESRIN, ESA
Conclusions
The end-to-end performance of CryoSat interferometer have been within system requirement from the beginning of the mission
The residual across-track accuracy and precision for BaselineC SARin L1B products has been assessed for science products
Towards BaselineD, the residual across-track accuracy and precision for the SARin L1B products can be still improved during on-ground processing
- More accurate mispointing angles can be obtained by applying the aberration correction
- A proper roll bias for each Star Tracker can be compensated
