© Copyright 2003 ABB Bomem Inc.
All rights reserved. - 7/14/03
Page 1
Remote Sensing Team
NASTER System
Definition Proposal
© Copyright 2003 ABB Bomem Inc.
Page 2
Overview
n
Review and comment the mid-IR requirements
n
Presentation of ABB’s current platform technology
n
Proposed approach for mid-IR NASTER
n
Proposed approach for initial NASTER
n
Discussion
© Copyright 2003 ABB Bomem Inc.
Page 3
Review of Requirements
n
The first NASTER Strawman requires wide coverage
and high spectral resolution
n
A modular concept has been developed to address as
much as possible the entire specification
n
Mid-IR NASTER Strawman requirements are less
constraining on the spectral coverage and resolution
n
Modules of the initial concept have been used to
address this new specification
n
We review the Mid-IR requirement first
Mid-IR Requirement Review
n
Spectral Limits (SL): 665 - 2860 cm−1 (3.5 - 15 microns)
n
1.4
© Copyright 2003 ABB Bomem Inc.
Page 4
1.2
We suggest to split the range in 2 bands at 1750 cm−1 (5.7
microns)
x 10
Spectral Coverage
1.4
x 10
-5
Radiance [W/(sr cm 2 cm -1 )]
1.2
1
0.8
GIFTS
EHS
FDS
AIRS
IAS I
CrIS
NAS TER
0.6
0.4
© Copyright 2003 ABB Bomem Inc.
Page 5
0.2
0
0
500
1000
1500
2000
2500
3000
Wavenumbers [cm -1 ]
• NASTER seems to be an Application test-bed for HES
• NASTER does not seem to be a Hardware test-bed for HES
Mid-IR Requirement Review
© Copyright 2003 ABB Bomem Inc.
Page 6
n
Spectral Resolution (SR): Selectable from 0.25 - 1.25 cm−1
n
Resolution limits maximum divergence inside interferometer
n
Off-axis pixels result in more constraining limitations
n
We suggest 0.25 cm−1 for the mid-wave and 0.5 cm−1 for the short wave and use off-axis IFOV’s with an inverse telescope (0.5)
Circular, on-axis
Mid-IR Requirement Review
n
© Copyright 2003 ABB Bomem Inc.
Page 7
n
Ground Resolution (GR): Contiguous at ≤ 500 meters
from 20 km flight altitude within single FOR
n
Defines IFOV of 25 mrad
n
We suggest 250 meters ground resolution (12.5 mrad IFOV)
Field of Regard (FOR): ≤ 2 km from 20 km flight altitude
n
Requirement suggests a 4x4 detector array
n
We suggest an 8x8 detector array to cover the 100 mrad square
FOR
Mid-IR Requirement Review
n
© Copyright 2003 ABB Bomem Inc.
Page 8
n
Along-track Scan Coverage (ATSC): ≤ 2 km FOR
contiguity at 20 km for an aircraft speed of 400 kts
n
Speed and IFOV defines observation time of 10 seconds
n
Motion compensation and 10 seconds observation time provide
contiguous along-track coverage
Cross-track Scan Coverage (CTSC): Selectable from 2
to 20 km, depending on spectral resolution, from 20 km
flight altitude for an aircraft speed of 400 kts
n
Defines a minimum observation time of 1 second
Mid-IR Requirement Review
n
Noise Equivalent delta Temperature (NEdT): Spectrally
random brightness temperature ≤ 0.25 K @ 0.25 cm−1
spectral resolution within the spectral range of 4.5 to 14
microns scene temperature of ≤ 260 K
NESR [W/(cm 2 sr cm -1 )]
© Copyright 2003 ABB Bomem Inc.
Page 9
10
10
10
10
-4
-6
-8
-10
500
Blackbody @ 260K
0.25K NEdT
CrIS Design Goals s c a led for
2.5 sec observation time and
required res olution
1000
1500
2000
-1
Wavenumber [cm ]
Required performances are similar to Design
Goals for CrIS
2500
3000
Mid-IR Requirement Review
n
Absolute Error (AE): Absolute brightness temperature
error ≤ 0.5 K within the spectral range of 4.5 to 14
microns scene temperature within the 200 - 300 K range
n
© Copyright 2003 ABB Bomem Inc.
Page 10
n
Main contributors are radiance uncertainty of calibration targets
and non-linearity of detector response
Calibration Sources (AE): Warm Blackbody, Ambient
Blackbody, Zenith Sky view
Mid-IR Requirement Review
© Copyright 2003 ABB Bomem Inc.
Page 11
n
Scan Angle Coverage (SAC): Selectable over a range
from zenith (180°) to Horizontal (at either + or - 90°) to
any combination of a set of viewing angle steps which
together provide contiguous coverage over a range from
±50 degrees about Nadir (0°)
n
Defines the scene selection continuous pointing range of ±50
degrees plus 5 discrete pointing position
n
Requires scanning without FOV rotation
50 degrees
2km
Mid-IR Requirement Review
n
Lifetime: ≥ 10 years through parts replacement over time
n
Build the system with standard parts used in commercial
standard products
n
Requires a single contractor responsible for the system
n
© Copyright 2003 ABB Bomem Inc.
Page 12
n
Contractor must have access to standard spare parts
Design type: Modular to allow for detector, spatial and
spectral resolution, and data system upgrades as
technology matures throughout the lifetime of the
NASTER
n
Use flexible electronics (digitally controlled interferometer)
n
Provide good transmission over a broad spectral range for the
interferometer
n
Provide sufficient resolution capability
Mid-IR Requirement Review
n
Operational Requirements: Command Uplink/Data
Downlink via over-the-horizon communications
n
Aircraft Compatibility: ER-2 (20 km), Proteus (17 km),
Global Hawk (20 km), and, if feasible, the new SCI
space plane “Spaceship 1” (55 km)
© Copyright 2003 ABB Bomem Inc.
Page 13
n
Low pressure not seen as a problem with components used
© Copyright 2003 ABB Bomem Inc.
Page 14
Overview
n
Review and comment the mid-IR requirements
n
Presentation of ABB’s current platform technology
n
Proposed approach for mid-IR NASTER
n
Proposed approach for initial NASTER
n
Discussion
ABB’s Current Platform Technology
n
© Copyright 2003 ABB Bomem Inc.
Page 15
n
Current platform technology consists of cube-corner
based interferometers
n
Provides low-cost, reliable, products 24/7 unattended operation
n
4-port, 2-port, and double-pass
n
Based on wishbone scan arm
n
Permanently aligned
Flat mirror DA interferometers not used in commercial
products
n
Porchswing scanning mechanism only supported for space
qualified projects
n
Flat mirror interferometers are optically efficient for large
imaging
ABB’s Current Platform Technology
n
New BMXS electronics
n
Digital scan servo control
n
© Copyright 2003 ABB Bomem Inc.
Page 16
n
Programmable scan profile
Flexible IR sampling based on high density fringe sampling
n
Constant clock sampling with phase detection
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Variable OPD sampling
n
Ethernet, LVDS, 10/100 base
n
Embedded Linux
n
May support dynamic alignment
ABB’s Current Platform Software
n
FTSW100 software suite includes
n
Run time module
n
Continuous spectrometer operation
n
Continuous housekeeping logging and diagnostics using multiple
I/O
n
© Copyright 2003 ABB Bomem Inc.
Page 17
n
CAN Bus and CAN Open
Control of measurement cycles
n
Configuration tools
n
Spectroscopy module
n
n
Radiometric functions
n
Chemometric functions
Database management
n
Propriatary SPC type files
n
Data can be exported to industry standard XML type
© Copyright 2003 ABB Bomem Inc.
Page 18
Overview
n
Review and comment the mid-IR requirements
n
Presentation of ABB’s current platform technology
n
Proposed approach for mid-IR NASTER
n
Proposed approach for initial NASTER
n
Discussion
© Copyright 2003 ABB Bomem Inc.
Page 19
Proposed Approach for Mid IR NASTER
n
2 Spectral Bands with band separation optics at 1750 cm−1
n
2 imaging, fiber coupled, detector modules
n
New COTS control electronics with Ethernet link
n
Digitally controlled spectrometer
n
Double pendulum, cube-corner, interferometer with good efficiency
from 300 to 2860 cm−1
n
Selectable resolution with 0.075 cm−1 as minimum spectral sampling
n
ILS compatible with spectral sampling of 0.25 cm−1 from 665 to 1750
cm−1, and 0.5 cm−1 from 1750 to 2860 cm−1
n
250 meters IFOV at 20 km altitude
n
10 seconds per interferometer sweep for 2 km swath
n
34 mm ∅ entrance pupil. f/1 optics at detector
n
8x8 FOR with contiguous coverage along-track
n
Motion compensation pointing mirror
n
2 on-board calibration targets (Ambient and Hot)
Proposed Approach for Mid IR NASTER
Instrument Control
Electronics
Calibration Targets
© Copyright 2003 ABB Bomem Inc.
Page 20
Spectrometer
Scene Selection Module
Modules Description
Instrument Integration & Support
Scene Selection Module
Spectrometer
n
Telescope
n
n
Pointing mirror with motion
compensation
Interferometer with control
electronics
n
Output optics
Control electronics
n
Detectors and readout electronics
n
© Copyright 2003 ABB Bomem Inc.
Page 21
Calibration Targets
Instrument Control Electronics
n
1 ambient (passive) cavity
n
1 hot (active) cavity
n
Data management
n
Temperature controller
n
Dashboard (user interface)
Mid IR NASTER - Resolution
n
Inverse telescope to reduce beam divergence inside interferometer
n
IFOV of 12.5 mrad
n
FOR made of 8x8 IFOV’s
ILS @ 2860 cm -1 . MPD = 1 cm.
2
Low er limit FWHM = 0.603 cm -1
1.5
ILS @ 1750 cm -1 . MPD = 2 cm.
3.5
3
Low er limit FWHM = 0.3015 cm -1
© Copyright 2003 ABB Bomem Inc.
Page 22
Instrument Line Shape
2.5
FWHM = 0.34127 cm
2
Instrument Line Shape
FWHM = 0.65367 cm
-1
As ymmetry = 0.24918 %
1
Shift of peak = 1.3775 cm -1
0.5
0
As ymmetry = 0.46937 %
-0.5
2852
Shift of peak = 0.84241 cm -1
1.5
2854
2856
2858
2860
2862
-1
Wavenumber [cm ]
1
0.5
0
-0.5
1746
-1
1747
1748
1749
1750
1751
-1
Wavenumber [cm ]
1752
1753
2864
2866
© Copyright 2003 ABB Bomem Inc.
Page 23
Mid IR NASTER - NEdT
n
Gold coated mirrors for pointing, telescope, and cube corners
n
CsI beamsplitter
n
PIR fiber to couple the interferometer to a PC-MCT linear array of 64
elements
n
D* of 4x1010 jones for the LW and 8x1010 jones for the SW
n
LW cut-off at 14.3 microns, SW cut-off at 5.7 microns
n
375 microns pixels (f/1 optics at the detector)
n
10 seconds observation time
n
2x2 pixel aggregation for 500 meters ground resolution
n
Instrument temperature at 25°C
n
SW is the middle portion of the full interferogram
Mid IR NASTER - NEdT
10
NEdT [K]
10
10
© Copyright 2003 ABB Bomem Inc.
Page 24
10
10
2
Nois e E quivalent delta Temperature. 0.25, 0.5 cm -1 Res olution.
0
-2
Total NEdT
Scene Shot noise
Background Shot noise
Detector & electronic noise
Quantization noise
Speed fluctuations & filter s lope
Speed fluctuations & delay mismatch
Sampling jitters
Requirement
-4
-6
500
1000
1500
2000
2500
Wavenumber [cm -1 ]
n
Detector noise limited
n
Second contributor is shot noise from self-emission
3000
Mid IR NASTER - NEdT
n
LW cut-off at 18.2 microns to get the entire CO2 absorption bands
n
D* of 2x1010 jones for the LW
n
Loss of performances in the water vapour bands from 1450 to 1750 cm−1
10
© Copyright 2003 ABB Bomem Inc.
Page 25
NEdT [K]
10
10
10
2
Noise Equivalent delta Tempera ture. 0.25, 0.5 cm -1 Res olution.
0
-2
Total NEdT
Scene Shot noise
Background Shot noise
Detector & electronic noise
Quantization noise
Speed fluctuations & filter slope
Speed fluctuations & delay mismatch
Sampling jitters
Requirement
-4
500
1000
1500
2000
Wavenumber [cm -1 ]
2500
3000
Mid IR NASTER - NEdT
n
Decrease the resolution to 2.5 cm−1 in the SW to meet requirement at
4.5 microns
10
NEdT [K]
10
10
© Copyright 2003 ABB Bomem Inc.
Page 26
10
10
2
Noise Equivalent delta Temperature. 0.25, 2.5 cm -1 Resolution.
0
-2
Total NEdT
Scene Shot noise
Background Shot noise
Detector & electronic noise
Quantization noise
Speed fluctuations & filter s lope
Speed fluctuations & delay mismatch
Sampling jitters
Requirement
-4
-6
500
1000
1500
2000
Wavenumber [cm -1 ]
2500
3000
© Copyright 2003 ABB Bomem Inc.
Page 27
Overview
n
Review and comment the mid-IR requirements
n
Presentation of ABB’s current platform technology
n
Proposed approach for mid-IR NASTER
n
Proposed approach for initial NASTER
n
Discussion
© Copyright 2003 ABB Bomem Inc.
Page 28
Proposed Approach for Initial NASTER
n
3 Spectral Bands (300 to 500 cm−1, 500 to 1650 cm−1, and 1650 to
2550 cm−1)
n
3 detectors in 1 Stirling cooler (no band separation optics)
n
New COTS control electronics with Ethernet link
n
Digitally controlled spectrometer
n
Selectable resolution with 0.075 cm−1 as minimum spectral
sampling
n
ILS compatible with spectral sampling of 0.075 cm−1 in the LW,
0.25 cm−1 in the MW, and 2.5 cm−1 in the SW
n
250 meters IFOV
n
1.25 second per interferometer sweep
n
34 mm ∅ entrance pupil. f/1 optics at detector
n
1x8 FOR with contiguous coverage along-track
n
+/- 34 degrees cross track scans with motion compensation
n
2 on-board calibration targets (Ambient and Hot)
Proposed Approach for Initial NASTER
Aircraft Motion
Ground Instantaneous Footprint
LW
34 degrees
MW
250m
© Copyright 2003 ABB Bomem Inc.
Page 29
2km
SW
2km
Resolution
ILS @ 500 cm -1. MPD = 6.6667 cm.
LW
12
-1
250m
-1
FWHM = 0.096437 cm
Instrument Line Shape
MW
Lower limit FWHM = 0.09045 cm
10
SW
2km
8
6
Shift of peak = 0.26322 cm
-1
4
2
0
-2
498.5
499
499.5
ILS @ 1650 cm-1. MP D = 2 cm.
4
-1
Lower limit FWHM = 0.3015 cm
-1
Lower limit FWHM = 3.015 cm
0.35
-1
FWHM = 0.32103 cm
FWHM = 3.0281 cm
0.3
2.5
-1
0.25
2
Shift of peak = 0.86883 cm
Instrument Line Shape
Instrument Line Shape
501
ILS @ 2500 cm -1. MP D = 0.2 cm.
3
© Copyright 2003 ABB Bomem Inc.
Page 30
500.5
0.4
3.5
-1
1.5
1
0.5
0
0.2
Shift of peak = 2.0107 cm
-1
0.15
0.1
0.05
0
-0.5
-1
1646
500
Wavenumber [cm -1]
-0.05
1647
1648
1649
1650
Wavenumber [cm -1]
1651
1652
1653
-0.1
2460
2470
2480
2490
2500
Wavenumber [cm -1]
2510
2520
2530
Proposed Approach for Initial NASTER
Noise Equiva lent de lta Tempera ture . 0.075, 0.25, 2.5 cm -1 Resolution.
10
NEdT [K]
10
10
10
© Copyright 2003 ABB Bomem Inc.
Page 31
10
10
1
0
-1
-2
Total NEdT
Scene Shot noise
Background Shot noise
Detector & electronic noise
Quantization noise
Speed fluctuations & filter slope
Speed fluctuations & delay mismatch
Sampling jitters
Requirement
-3
-4
0
500
1000
1500
2000
2500
-1
Wavenumber [cm ]
n
D* = 4×109 (LW), 4×1010 (MW), and 1×1011 (SW) jones
n
MW and SW are middle portions of full resolution interferogram
n
1 sweep, IFOV’s aggregation to 500 meters square
Proposed Approach for Initial NASTER
10
10
NEdT [K]
10
10
10
© Copyright 2003 ABB Bomem Inc.
Page 32
10
10
1
Noise Equiva lent de lta Tempera ture . 0.25, 0.25, 2.5 cm -1 Resolution.
0
-1
-2
-3
Total NEdT
Scene Shot noise
Background Shot noise
Detector & electronic noise
Quantization noise
Speed fluctuations & filter slope
Speed fluctuations & delay mismatch
Sampling jitters
Requirement
-4
-5
0
500
1000
1500
2000
Wavenumber [cm -1]
n
3 sweeps, IFOV’s aggregation to 500 meters square
2500
Proposed Approach for Initial NASTER
10
10
NEdT [K]
10
10
10
© Copyright 2003 ABB Bomem Inc.
Page 33
10
10
Noise Equiva lent de lta Tempera ture . 2.5, 2.5, 2.5 cm -1 Resolution.
1
0
-1
-2
-3
Total NEdT
Scene Shot noise
Background Shot noise
Detector & electronic noise
Quantization noise
Speed fluctuations & filter slope
Speed fluctuations & delay mismatch
Sampling jitters
Requirement
-4
-5
0
500
1000
1500
2000
2500
-1
Wavenumber [cm ]
n
33 sweeps, IFOV’s aggregation to 500 meters square
© Copyright 2003 ABB Bomem Inc.
Page 34
Summary for Initial NASTER
Range
Desired
100 – 2500 cm−1
Proposed
300 – 2500 cm−1
Resolution
0.025 cm−1
0.075 cm−1 < 500 cm−1
0.25 cm−1 < 1650 cm−1
2.5 cm−1 < 2500 cm−1
Ground
resolution
FOR
500 m x 500 m
250 m x 250 m
2 km
Observation time 10 sec
Cross-track
2 – 20 km
NedT (260 K)
0.2 – 1 K
2km
aggregate to 4x1
1.25 sec
2 – 20 km (0.825 cm−1)
1.2 K < 500 cm−1
0.05 – 1 K < 1650 cm−1
0.7 – 2.5 K < 2500 cm−1
Proposed Approach for Initial NASTER
© Copyright 2003 ABB Bomem Inc.
Page 35
n
MR type (AERI) interferometers with higher resolution and larger
aperture considered in other airborne and space programs
© Copyright 2003 ABB Bomem Inc.
Page 36
SOFIS FTS On-board GCOM-A1
© Copyright 2003 ABB Bomem Inc.
Page 37
Overview
n
Review and comment the mid-IR requirements
n
Presentation of ABB’s current platform technology
n
Proposed approach for mid-IR NASTER
n
Proposed approach for initial NASTER
n
Discussion