APEX - Airborne Prism EXperiment Walter Debruyn Vito/TAP Boeretang 200 B-2400 Mol...
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Transcript of APEX - Airborne Prism EXperiment Walter Debruyn Vito/TAP Boeretang 200 B-2400 Mol...
APEX - Airborne Prism EXperiment
Walter Debruyn
Vito/TAP
Boeretang 200
B-2400 Mol
http://www.apex-esa.org
Scope of APEX
APEX is a hyperspectral airborne simulator for the support and development of future hyperspectral spaceborne missions.
APEX will be able to Simulate, Calibrate, and Validate
the planned European imaging spectrometer missions (ESA Land Mission, CHRIS/PROBA, MERIS/ENVISAT).
APEX will foster the use of imaging spectrometer data in Europe and will support the application development of imaging spectroscopy products.
APEX is the first European perspective of an imaging spectrometer covering the full solar reflected range.
APEX in the Context of ESA
Partial Simulation Capabilities Only
Earth ExplorerMission(s)
LSPIM (Phase A)
TechnologyDemonstrator
Science Demonstrator& Data Simulator
CHRIS on PROBA
Further advancementof the Land Mission
New Land Mission Radiometric Transfer Standard(MERIS, CHRIS, etc.)
Co–Investigator
APEX Setup (Phase B)
Belgian PRODEXOffice
Swiss PRODEXOffice
TechnicalDirectorate
Earth Observation
PRODEXOffice
Principal Investigator
Scientific ConsultancyGroup (SCG)
Swiss PRODEXCommittee (PPK)
Industrial Prime
IndustrialSubcontr.
IndustrialConsultant
IndustrialSubcontr.
Industrial Con-sultant
National Entities Institutes Industry
Alcatel Space
France
DSS–OIP
Belgium
Alcatel Space
Switzerland
SF
Switzerland
DLR / DFD
Germany
APEX Timeline
Pre–Phase A
Phase A
Phase B
Phase C/D
Phase E
Post–Phase E
Feasibility Studyof APIS and
AMIRIS
1/96 7/96 8/96 2/98 10/98 3/00 4/01(?) 6/03(?) 6/03 6/08 6/13
Feasibility Studyof APEX and
Critical DesignReview (CCN2) Detail Specifica-
tions andBreadboards
HardwareConstruction
and Implementation ESA Operation
and Exploitation
APEX Optimization Scheme
Optimization Priorities Signal to noise,
Transmission of optical design Pushbroom principle Minimizing noise of detectors and electronics
Spectral uniformity, Coregistration of spectral channels and bands Minimizing geometric abberation (‘frown’ and ‘smile’)
Stability, and Pressure/temperature controlled environment Pre and post flight on board calibration
Repeatability. Laboratory and vicarious calibration Navigational system (Positional and attitude recording system)
APEX Specifications (1 of 2)
Parameter Requirement
Field of View (FOV) ± 14 deg
Instantaneous Field of View (IFOV) 0.5 mrad
Flight altitude 4,000 - 10,000 m.a.s.l. (7,500 m nominal)
Spectral channels VIS/NIR: 124; SWIR: 176
Spectral range 400 – 2500 nm
Spectral sampling interval 600 – 780 nm: < 5 nm400 – 600 nm and 780 – 1050 nm: < 10 nm; optimized for SNR
1050 – 2500 nm: < 10 nm
Spectral sampling width < 1.5 * Spectral sampling interval
Center wavelength accuracy < 0.2 nm
Spectral sampling width accuracy < 0.02 * Spectral sampling width
PSF (Point Spread Function) PSF 1.75 * IFOV
Smile < 0.1 pixel
Frown < 0.1 pixel
APEX Specifications (2 of 2)
Parameter Requirement
Bad pixels None (requirement after electronics)
Scanning mechanism Pushbroom
Absolute radiometric calibration accuracy 2%
Storage capacity on board (online) > 50 GByte
Dynamic Range 16 bit
Positional knowledge 20% of the ground pixel size (DGPS required)
Attitude knowledge 20% of IFOV (accelerometers, gyros, inertial navigation system required)
Navigation system, flight line repeatability ± 5% of FOV
Positional and attitude data Recording of data onto a housekeeping channel
Reliability 99 % successful data acquisitions for all flights during each year of operation
Optical head dimensions Must fit in standard mount
Signal To Noise Levels
Simulated APEX Spectral Response
APEX - Airborne Prism Experiment
APEX BlockdiagramAircraft
Processing and Archiving Facility
Data Storage Preprocessing
Processing Data Distribution
Stabilized Platform
Laboratory Calibration
Detector / FEE
Video Electronic Unit
SW
IR
De
tecto
r / F
EEVIS
Op
tom
ech
an
. Pa
rt
Data Recording System: Framegrabber Unit User Interface Unit
Monitoring Unit Power Supply
DGPS
INS
Calibration Means
Protective Window
Net- work
FOV
Gro
un
d
Ima
ge
r
Processing and Archiving Facility
Data storagePre-processing
ProcessingData Distribution
APEX raw data simulation
Simulated raw sensor data as acquired by the APEX system, including dark current and internal integrating sphere measurements. This cube contains all data acquired for one imaging section (simulation based on HYMAP measurements).
The PAF Processing Levels
data download and segregation
Level 2B/C
orthorectification
system correctioncalibration
linking parameters: view angle, view distance, terrain height
atmospheric andradiometric correction
Level 1D
Level 2A
Level 0B
Level 3
laboratory and in-flightcalibration data
in-flight auxiliary data
DEM, flightpath
meteorological measurements
application processing
APEX (near) future
Phase C/D operational organization- Scientific Team : RSL- Operations Team : Vito
2000 : Calibration test site studied :
HYMAP and CASI flight campaigns
2001: AVIRIS flight campaigns throughout Europe
(ESA initiative, Vito operations)
APEX Outlook
Completing the - instrument
- processing and archiving facility
- calibration home base
in Spring 2003 is achievable
Additional ESA study (detectors, calibration) [institutes]and breadboarding of critical components [industry]are ongoing
Hardware construction and implementation (phase C/D) will start ASAP