Rostock, 2013-09-06 – 1
Rostock – 2013-09-06
NAVIGATION AND REMOTE SENSING PAYLOADS AND METHODS OF THE
SARVANT UNMANNED AERIAL SYSTEM
P. Molina, P. Fortuny, I. ColominaInstitute of Geomatics -- Castelldefels (ES)
M. Remy, K.A.C. Macedo, Y.R.C. Zúnigo, E.Vaz, D. Lübeck, J. MoreiraOrbisat Remote Sensing – Campinas, Sao Jose dos Campos (BR)
M. BlázquezGeonumerics – Barcelona (ES)
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THE LARGEST TROPICAL RAINFOREST IN THE WORLD
6 million km2 of rainforestover 9 countries
30m to 100m height trees(5% light penetration)
Unseen terrain, rivers…
Suitability of UAVs���� lower-cost (specially
in small areas)���� ease of operation
Challenge for UAVs���� sensors
Needs:���� topography���� imagery���� vegetation analysis
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THE AERIAL PLATFORM
Operational flying heights 1000 m
Operational flying speed 200 km/h
MTOW 120 kg
Payload Weight 45 kg
Endurance 5h
Length x Wing span 3,8m x 6,2m
Designed by Aeroalcool (Brasil), avionics by AGX (Brasil)
� scan and produce topography of 500 km2 with SAR
� sensor creates the platform
Orbisat (Embraer) and Institute of Geomatics collaborate for SARVANT HW/SW acquisition, navigation and remote sensing
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SYNTHETIC APERTURE RADAR (SAR): SENSOR
Volume and weight ~ 0.76 x 0.34 x 0.36 m3 , 30 kg
Bands P (250-500 MHz) and X (8-12 GHz)
Power 30W (peak) , 0.6W (avg.) (X-band) 50W (peak) , 1.0W (avg.) (P-band)
Range Resolution ≥ 0.5 m (X-band) ≥ 1.5 m (P-band)
Cross-range Resolution
≥ 0.11 m (X-band) ≥ 0.5 m (P-band)
Look angle from nadir
20 to 60 degrees (X-band) 10 to 60 degrees (P-band)
Interferometric (InSAR) baseline
= 0.25 m (X-band, single-pass) ≤ 50 m (P-band, repeat-pass)
Altimetric accuracy 1 to 5 meter (depends on vegetation)
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SYNTHETIC APERTURE RADAR (SAR): DSM and DTM
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SYNTHETIC APERTURE RADAR (SAR): DSM and DTM
Digital Terrain Model (DTM) Digital Surface Model (DSM)
Independent from illumination and weather conditions
Unique development in the world (civilian)
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SYNTHETIC APERTURE RADAR (SAR): BIOMASS ESTIMATION
Tree height deeply correlated with Biomass (highest biomass levels in the world)
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SYNTHETIC APERTURE RADAR (SAR): DRAINAGE
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SYNTHETIC APERTURE RADAR (SAR): SUBSIDENCE
11cm
-11cm
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ORIENTATION PAYLOAD: HIGH-GRADE INS AND GNSS
Navigation payload� low-grade sensors for auto-piloting
- stable guidance along scanning lines (�SAR coherence)
Orientation payload� SAR requirements
- state-of-the-art geodetic grade orientation payload� position ~ centimeters, � attitude ~ hundredth of degree
[On-board] PC104-compatible acquisition and synchronization system:
- DMARS-I IMU (high-end tactical grade)- Novatel OEM3 GNSS receiver - Mother board, clock board, power supply
[Off-line] INS/GNSS tight coupling- Carrier-phase differential - Precise Point Positioning (PPP)
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OPTICAL PAYLOAD: RGB/NIR DOUBLE CAMERA
Visible band (below cloud level!)
‘Medium’ format RGB cameras (80 Mpx):
- Phase One iXA, Hasselblad H4D-40 � price!
- for concept demonstration, MILC (Sony NEX-7) 24.3 Mpx � 25 cm GSD
Agricultural/environmental applications
Coverage of the infrared band:
- Multi- or hyper-spectral solutionsavailable for UAVs (MiniMCA, Rikola)
- Replace filters to reach NIR/SWIR
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OPTICAL PAYLOAD: RGB/NIR DOUBLE CAMERA
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ORIENTATION METHOD: INTEGRATED SENSOR ORIENTATION
INS/GNSS tPVA + image coordinates (minimum overlap) + GCPs
On-the-job sensor & system calibration
Computational burden++, Accuracy, robustness++
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ORIENTATION METHOD: DIRECT SENSOR ORIENTATION
INS/GNSS tPVA (no overlap requirement)
Previous sensor and system calibration
Computational burden, Accuracy, robustness
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ORIENTATION METHOD: FAST-AT
INS/GNSS tPVA + image-coordinates for GCPs + GCPs
On-the-job system calibration and sensor pre-calibration
Computational burden+, Accuracy, robustness+
- Suitable for ill-textured areas
- SAR Corner reflectors as GCPs
-
Fast-AT does not support:“Unstable” camera calibrationLow-grade navigation sensors
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CURRENT AND FUTURE WORK
Development of the double-optical payload for SARVANT� HW/SW acquisition system� Camera calibration
Aerial platform:- flown with remote control, awaiting authorization for auto-pilot flight
Synthetic Aperture Radar:- finishing final boards; backplane is being produced.
Assessment of Fast-AT with actual UAV data
THANKS!
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