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!