Sensor Systems of the NASA Airborne Science Program

Several large remote sensing systems are considered as NASA facility instruments, in part because they support multiple science disciplines, and a variety of NASA science objectives. They are supported by managers in the ESD Research and Analysis program, and/or the EOS Project Science Office, and are made available to the wider NASA science community via the flight request process. In most cases, instrument operating and data processing costs are recovered from the requesting individual or their sponsors.

The systems described here reside at either Ames Research Center or the Jet Propulsion Laboratory (noted as ARC or JPL, respectively.)

AVIRIS (Airborne Visible and Infrared Imaging Spectrometer - JPL)

AVIRIS parameters are as follows:

• IFOV: 1 mrad
• Ground Resolution: 66 feet (20 meters) at 65,000 feet
• Total Scan Angle: 30 degrees
• Swath Width: 5.7 nmi (10.6 km) at 65,000 feet
• Digitization: 12-bits

Notes: This instrument is flown on the ER-2 aircraft. All data collection missions are coordinated through JPL. 

(See the AVIRIS homepage at http://aviris.jpl.nasa.gov/)

AVIRIS Instrument undergoing pre-flight checks

AVIRIS Image of Mount St. Helens

MODIS Airborne Simulator (ARC)

The MODIS Airborne Simulator (MAS) is a multispectral scanner configured to approximate the Moderate-Resolution Imaging Spectrometer (MODIS), an instrument to be orbited on the NASA EOS-AM1 platform. MODIS is designed to measure terrestrial and atmospheric processes. The MAS was a joint project of Daedalus Enterprises, Berkeley Camera Engineering, and Ames Research Center. The MODIS Airborne Simulator records fifty spectral bands, configured as follows:

• Spectral Bands: 50 (16-bit resolution)
• IFOV: 2.5 mrad
• Ground Resolution: 163 feet (50 meters at 65,000 feet)
• Swath Width: 19.9 nmi (36 km)
• Total Scan Angle: 85.92 degrees
• Pixels/Scan Line: 716
• Scan Rate: 6.25 Hz
• Ground Speed: 400 kts (206 m/second)
• Roll Correction: Plus or minus 3.5 degrees (approx.)

See the webpage http://mas.arc.nasa.gov

MODIS Airborne Simulator

MODIS Imagery from the Alaska Campaign April 1995

MODIS Imagery from the WINCE Campaign

MODIS Imagery of the Arkansas River Gorge, Colorado

MASTER (MODIS/ASTER Airborne Simulator - ARC)

The MASTER is similar to the MAS, with the thermal bands modified to more closely match the NASA EOS ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) satellite instrument, which is scheduled for launch in 1998. It is intended primarily to study geologic and other Earth surface properties. Flying on both high and low altitude aircraft, the MASTER will be operational in early 1998. Its fifty spectral bands are configured as follows:

• Spectral Bands: 50 (16-bit resolution)
• IFOV: 2.5 mrad
• Ground Resolution: 12-50 meters (variable w/ altitude)
• Total FOV: 85.92 degrees
• Pixels/Scanline: 716
• Scan Rate: 6.25 - 25 Hz

(See the homepage at http://masterweb.jpl.nasa.gov)

MASTER Instrument in the Calibration Lab

Autonomous Modular Sensor (AMS)

The Autonomous Modular Sensor (AMS) is an airborne scanning spectrometer that acquires high spatial resolution imagery of cloud and surface features from its vantage point on-board low and medium altitude research aircraft. Data acquired by AMS is  helping to define, develop, and test algorithms for use in a variety of scientific programs that emphasize the use of remotely sensed data to monitor variation in environmental conditions, assess global change, and respond to natural disasters.

Wildfire/Land Surface Scanner

Ocean Color Imager

Digital Cirrus Camera (DCS)

• Lens: Zeiss (Germany) 14 lenses available (5º to 60º Total FOV)
• Camera body: Hasselblad (Sweden)
• Camera Back & 16M pixel (4K x 4K) CCD array: Kodak (USA)
• “Stand-alone” or computer-controlled operation
• Produces either “color-infrared” or “natural-color” imagery
• “Raw” image size: ~16Mbyte / Processed image size: ~48 / 96Mbyte
• Recording media: 8GB Compact Flash (~400 images)
• Environmental: >100,000 ft altitude and –15 degrees C
• GPS data and ancillary file appended to each image
• Size: 28cm L x 15cm H x 10cm W (11”L x 6”H x 4”W)
• Weight: 3.2Kg (~7 pounds)

Georectification of DCS Imagery
• DCS can operate minimally as a “Tracker”
– Replacement for RC-10 when used for experiment support
– Grand Canyon mosaic created in Tracker Mode
• First-order generic radial lens correction
– Test conducted using 60% overlapping frames (San Francisco)
– Mis-registration of 6 to 7 pixels at corner from center of image
(~0.2%)
• Zeiss lens metric calibration (lens specific)
– Expectation: ~1 pixel frame to frame registration over flat terrain
• Level 1 georectification using ER-2 INU and L1/L2 GPS
• Level 2 georectification using Applanix Pos AV and DEM

DCS Camera

Rear View of DCS

San Francisco Bay Imaged with DCS

POS-AV

Applanix Position and Orientation System for Airborne Vehicles (POS AV)
provides navigation and orientation data for geocoding and georectifying
airborne sensor information.
Data such as geographic position (latitude, longitude and attitude), velocity,
acceleration, angular rate, orientation (roll and pitch), heading and
performance metrics are available in real-time and through post-processing.
POS AV is comprised of a POS Computer System (PCS), Inertial
Measurement Unit (IMU) and a Global Positioning System (GPS) antenna

POS AV by Applanix