**Sensor Systems**

**of the**

**NASA Airborne Science Program**

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**[Sensor Systems of the NASA Airborne Science Program]{.underline}**

The National Aeronautics and Space Administration maintains a variety of
aircraft and sensor systems dedicated to the support of remote sensing
research. Two Lockheed ER-2s (S-model U-2,) a DC-8, and several U.S.
Dept. of Energy aircraft provide multi-level platforms for both NASA and
investigator-owned sensors. Data are collected for the atmospheric,
land, and ocean processes aspects of the NASA Earth Science program, as
well as for universities and other government agencies. Several of these
systems are being used to validate algorithms for the NASA Earth
Observing System.

The NASA aircraft, located at Dryden Flight Research Center, are used as
test-beds for advanced sensor design and satellite simulation, as well
as to support scientific and operational data collection campaigns.
Numerous sensor systems are in use and under development by NASA,
including multispectral imaging devices, a SAR system, and a suite of
large-format mapping cameras. All instruments are spectrally, spatially,
and radiometrically calibrated on a routine basis. The aircraft
themselves are equipped with navigation systems that continuously record
GPS location and platform attitude data.

The systems described here are facility NASA sensors, and are generally
available to the science community; they reside at either Ames Research
Center or the Jet Propulsion Laboratory (noted as ARC or JPL,
respectively.) There are a variety of other sensors that fly on these
aircraft that are owned by individual investigators, which are not
within the scope of this document.

**[AVIRIS (Airborne Visible and Infrared Imaging Spectrometer -
JPL)]{.underline}**

The AVIRIS is the second in a series of imaging spectrometer instruments
developed at the Jet Propulsion Laboratory (JPL) for earth remote
sensing. This instrument uses scanning optics and four spectrometers to
image a 614 pixel swath simultaneously in 224 contiguous spectral bands.

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

[Spectrometer]{.underline} [Wavelength]{.underline} [#Bands]{.underline}
[Bandwidth]{.underline}

1 0.41 - 0.70 μm 31 9.4 nm

2 0.68 - 1.27 μm 63 9.4 nm

3 1.25 - 1.86 μm 63 9.7 nm

4 1.84 - 2.45 μm 63 9.7 nm

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

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

**[MODIS Airborne Simulator (ARC)]{.underline}**

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   Band     Bandwidth   Spectral             Spectral   Band      Bandwidth   Spectral
             center                                               center                

  Channel    (µm )    (µm )       Range                Channel    (µm )     (µm )       Range

  1          0.4649   0.0397      0.4451-0.4848        26         3.1192    0.1616      3.0384-3.2000

  2          0.5494   0.0417      0.5285-0.5703        27         3.2809    0.1486      3.2066-3.3552

  3          0.6550   0.0511      0.6294-0.6805        28         3.4330    0.1617      3.3521-3.5138

  4          0.7024   0.0415      0.6816-0.7231        29         3.5940    0.1539      3.5170-3.6709

  5          0.7431   0.0420      0.7221-0.7641        30         3.7449    0.1449      3.6724-3.8174

  6          0.8248   0.0427      0.8034-0.8461        31         3.9069    0.1602      3.8267-3.9870

  7          0.8667   0.0414      0.8460-0.8874        32         4.0707    0.1554      3.9929-4.1484

  8          0.9072   0.0409      0.8867-0.9276        33         4.1699    0.0669      4.1365-4.2034

  9          0.9476   0.0397      0.9277-0.9674        34         4.4029    0.1255      4.3401-4.4656

  10         1.6422   0.0519      1.6163-1.6682        35         4.5404    0.1512      4.4648-4.6160

  11         1.6975   0.0505      1.6722-1.7228        36         4.6979    0.1591      4.6184-4.7775

  12         1.7499   0.0506      1.7245-1.7752        37         4.8536    0.1516      4.7778-4.9294

  13         1.8014   0.0491      1.7768-1.8259        38         5.0033    0.1468      4.9298-5.0767

  14         1.8548   0.0489      1.8303-1.8792        39         5.1588    0.1400      5.0888-5.2288

  15         1.9044   0.0487      1.8801-1.9288        40         5.3075    0.1327      5.2412-5.3738

  16         1.9553   0.0483      1.9312-1.9794        41         5.3977    0.0755      5.3590-5.4365

  17         2.0048   0.0487      1.9804-2.0291        42         8.5366    0.3950      8.3391-8.7341

  18         2.0551   0.0484      2.0309-2.0793        43         9.7224    0.5365      9.4541-9.9906

  19         2.1037   0.0486      2.0794-2.1280        44         10.5071   0.4579      10.278-10.736

  20         2.1532   0.0483      2.1291-2.1774        45         11.0119   0.4710      10.776-11.247

  21         2.2019   0.0481      2.1779-2.2259        46         11.9863   0.4196      11.776-12.196

  22         2.2522   0.0486      2.2278-2.2675        47         12.9013   0.3763      12.713-13.089

  23         2.3021   0.0487      2.2777-2.3265        48         13.2702   0.4584      13.041-13.500

  24         2.3512   0.0476      2.3274-2.3750        49         13.8075   0.5347      13.540-14.075

  25         2.4005   0.0483      2.3764-2.4246        50         14.2395   0.3775      14.051-14.428
  ---------- -------- ----------- --------------- ---- ---------- --------- ----------- ---------------

Sensor/Aircraft Parameters:

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 homepage at
http://ltpwww.gsfc.nasa.gov/MODIS/MAS/Home.html[)]{.underline}

**[MASTER (MODIS/ASTER Airborne Simulator - ARC)]{.underline}**

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   Band     Bandwidth   Spectral           Spectral   Band     Bandwidth   Spectral
             center                                             center               

  Channel    (µm )    (µm )       Range              Channel    (µm )    (µm )       Range

  1          0.460    0.04        0.440-0.480        26         3.150    0.15        3.075-3.225

  2          0.500    0.04        0.480-0.520        27         3.300    0.15        3.225-3.375

  3          0.540    0.04        0.520-0.560        28         3.450    0.15        3.375-3.525

  4          0.580    0.04        0.560-0.600        29         3.600    0.15        3.525-3.675

  5          0.660    0.06        0.630-0.690        30         3.750    0.15        3.675-3.825

  6          0.710    0.04        0.690-0.730        31         3.900    0.15        3.825-3.975

  7          0.750    0.04        0.730-0.770        32         4.050    0.15        3.975-4.125

  8          0.800    0.04        0.780-0.820        33         4.200    0.15        4.125-4.275

  9          0.865    0.04        0.845-0.885        34         4.375    0.15        4.275-4.875

  10         0.905    0.04        0.885-0.925        35         4.500    0.15        4.425-4.575

  11         0.945    0.04        0.925-0.965        36         4.650    0.15        4.575-4.725

  12         1.625    0.05        1.600-1.650        37         4.800    0.15        4.725-4.875

  13         1.675    0.05        1.650-1.700        38         4.950    0.15        4.875-5.025

  14         1.725    0.05        1.700-1.750        39         5.100    0.15        5.025-5.175

  15         1.775    0.05        1.750-1.800        40         5.250    0.15        5.175-5.325

  16         1.825    0.05        1.800-1.850        41         7.900    0.4         7.70-8.10

  17         1.875    0.05        1.850-1.900        42         8.300    0.4         8.10-8.50

  18         1.925    0.05        1.900-1.950        43         8.700    0.4         8.50-8.90

  19         1.975    0.05        1.950-2.000        44         9.100    0.4         8.90-9.30

  20         2.075    0.05        2.050-2.100        45         9.700    0.4         9.50-9.90

  21         2.160    0.05        2.135-2.185        46         10.100   0.4         9.90-10.30

  22         2.210    0.05        2.185-2.235        47         10.625   0.65        10.30-10.95

  23         2.260    0.05        2.235-2.285        48         11.300   0.7         10.95-11.65

  24         2.3295   0.065       2.297-2.362        49         12.050   0.5         11.80-12.30

  25         2.3945   0.065       2.362-2.427        50         12.750   0.5         12.50-13.00
  ---------- -------- ----------- ------------- ---- ---------- -------- ----------- -------------

Sensor/Aircraft Parameters:

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 asterweb.jpl.nasa.gov)

[**AirMISR (Airborne Multi-angle Imaging SpectroRadiometer -
JPL**)]{.underline}

This is an airborne instrument for obtaining multi-angle imagery similar
to that of the satellite-borne MISR instrument, which is designed to
contribute to studies of the Earth\'s ecology and climate. AirMISR flies
on the NASA-owned ER-2 aircraft. It was built for NASA by the Jet
Propulsion Laboratory in Pasadena, California.

(See the homepage at http://www-misr.jpl.nasa.gov/armain.html)

**[AIRSAR (Airborne Synthetic Aperture Radar - JPL)]{.underline}**

This is an experimental system managed by the NASA Jet Propulsion
Laboratory (JPL,) that flies on the DC-8 aircraft. It simultaneously
acquires data in the L, P, and C-Bands in multiple polarizations.

The system was designed in support of the Space Shuttle Imaging Radar-C
(SIR-C) program, but is widely used in the SAR remote sensing research
community.

(See the homepage at http://southport.jpl.nasa.gov/airsardesc.html)

**[TMS (Thematic Mapper Simulator - ARC)]{.underline}**

This is a Daedalus AADS-1268 scanner that flies on the ER-2 aircraft and
simulates the LANDSAT TM instrument, with slightly higher spatial
resolution, and several extra bands.

[Band]{.underline} [Wavelength μm]{.underline}

1 0.42- 0.45

2 (TM1) 0.45- 0.52

3 (TM2) 0.52- 0.60

4 0.60- 0.62

5 (TM3) 0.63- 0.69

6 0.69- 0.75

7 (TM4) 0.76- 0.90

8 0.91- 1.05

9 (TM5) 1.55- 1.75

10 (TM7) 2.08- 2.35

11 (TM6) High Gain 8.5- 14.0

12 (TM6) Low Gain 8.5- 14.0

Spatial Resolution: 25 meters (all bands) from 19.8 km (65,000 ft.)

Total Field of View: 42.5 degrees

IFOV: 1.25 mrad

Notes: All bands are 8-bit digitization; onboard blackbody sources are
carried for thermal calibration.

The system is scheduled to be upgraded to 16-bit resolution in late
1998.

(See the homepage at http://asapdata.arc.nasa.gov/Sensors.htm)

**[AOCI (Airborne Ocean Color Imager - ARC)]{.underline}**

The AOCI is a high altitude multispectral scanner built by Daedalus
Enterprises, designed for oceanographic remote sensing. It provides
10-bit digitization of eight bands in the visible/near-infrared region
of the spectrum, plus two 8-bit bands in the near and thermal infrared.
The bandwidths are as follows:

[Channel]{.underline} [Wavelength, μm]{.underline}
[Digitization]{.underline}

1 0.436 - 0.455 10 bit

2 0.481 - 0.501 "

3 0.511 - 0.531 "

4 0.554 - 0.575 "

5 0.610 - 0.631 "

6 0.655 - 0.676 "

7 0.741 - 0.800 "

8 0.831 - 0.897 "

9 0.989 - 1.054 8 bit

10 8.423 - 12.279 "

Spatial Resolution: 50 Meters from 19.8 km (65,000 ft.)

Total Field of View: 85 degrees

IFOV: 2.5 mrad

Note: The system is scheduled to be upgraded to 16-bit resolution in
late 1998.

(See the homepage at http://asapdata.arc.nasa.gov/Sensors.htm)

**[MAMS (Multispectral Atmospheric Mapping Sensor - ARC)]{.underline}**

The MAMS is a modified Daedalus Scanner flown aboard the ER-2 aircraft.
It is designed to study weather related phenomena including storm system
structure, cloud-top temperatures, and upper atmospheric water vapor.
The scanner retains the eight silicon-detector channels in the
visible/near-infrared region found on the Daedalus Thematic Mapper
Simulator, with the addition of four channels in the infrared relating
to specific atmospheric features. The spectral bands are as follows:

[Channel]{.underline} [Wavelength, μm]{.underline}

1 (LSBs for Channels 9-12)

2 0.45 - 0.52

3 0.52 - 0.60

4 0.57 - 0.67

5 0.60 - 0.73

6 0.65 - 0.83

7 0.72 - 0.99

8 0.83 - 1.05

9 3.55 - 3.93 (6.20- 6.90 optional)

10 3.55 - 3.93 ( \" \" \" )

11 10.3 - 12.1

12 12.5 - 12.8

Spatial Resolution: 50 or 100 meters from 19.8 km (65,000 ft.)

Total Field of View: 85.92 degrees

IFOV: 2.5 or 5.0 mrad (selectable)

Notes: Channels 9 - 12 are digitized to 10 bits; all others are 8-bit.
Blackbody sources are carried for IR calibration. The system is
scheduled to be upgraded to 16-bit resolution in late 1998.

(See the homepage at http://wwwghcc.msfc.nasa.gov/irgrp/mams)

**[Electro-Optic Camera (ARC)]{.underline}**

This is a three channel framing camera designed for the ER-2, consisting
of three 2048 X 2048 element, cooled silicon arrays mounted on a prism
behind a single lens. The channels cover the green, red, and near-IR
portions of the spectrum; each channel can be further narrowed within
its respective range with a removable narrow-band filter mounted on the
dichroic prism face.

[Channel]{.underline} [Wavelength, μm]{.underline}

1 .525 - .570

2 .620 - .700

3 .810 - .850

Total Field of View: 60 degrees

IFOV: 0.52 mrad

Digitization: 12 bits

(See the homepage at http://asapdata.arc.nasa.gov/Sensors.htm)

**[Aerial Camera Systems (ARC)]{.underline}**

The ER-2 can carry a variety of film camera systems. Several of these
cameras are calibrated for precision photogrammetry, and the film may be
used to generate digital ortho-photos or high-resolution digital
elevation models.

Camera Film Ground Nominal

[Type]{.underline} [Lens]{.underline} [Format]{.underline}
[Coverage]{.underline} [Resolution]{.underline} [Scale]{.underline}

RC-10 6\"/f4 9\" X 9\" 30 X 30km 3.0-8.0m 1:130,000

RC-10 12\"/f4 9\" X 9\" 15 X 15km 1.5-4.0m 1:65,000

HR-732 24\"/f8 9\" X 18\" 7.4 X 15km 0.6-3.0m 1:32,500

IRIS 24\"/f3.5 4.5\" X 35\" 3.7 X 40km 0.3-2.0m 1:32,500

(Panoramic) (Nadir)

Note: Spatial parameters are for the ER-2 at 19.8km altitude; actual
resolution is a function of target contrast. Missions are typically
flown with 60% forward frame overlap for stereo coverage. RC-30 cameras
are also available on the Dept. of Energy aircraft.

(See the homepage at http://asapdata.arc.nasa.gov/Sensors.htm)

**[STARLink]{.underline}**

The Satellite Telemetry And Return Link (STARLink) system provides
real-time, continuos relay of digital sensor data from the ER-2 aircraft
via the NASA Tracking & Data Relay Satellite System (TDRSS.) It is
currently configured to send 48 Mb/sec of data to the ground station,
and 400 Kb/sec simultaneously back up to the aircraft for sensor command
and control. The system offers nearly global coverage, with the data
being captured to disk arrays at Ames Research Center.

(See the homepage at http://hawkeye.arc.nasa.gov)

**[Other Imaging systems]{.underline}**

The ER-2 and DC-8 aircraft are also equipped with video systems for
tracking purposes, which are scheduled to be replaced by HDTV devices.

**[Data Availability]{.underline}**

All of the data collected by these systems is publicly available through
U.S. Government agencies. Archives exist at the EROS Data Center of the
U.S. Geological Survey in Sioux Falls, South Dakota; and within the NASA
EOS-DAACs (Earth Observing System - Distributed Active Archive Centers.)
Further information is available from the NASA Ames Research Center
Aircraft Sensor Facility at (650) 604-6252.

**[Flight Documentation and Data Archive Searches]{.underline}**

The following is the web site for flight documentation as published by
the Airborne Sensor Facility at NASA Ames Research Center:

http://asapdata.arc.nasa.gov/er-2fsr.html

Additional information regarding flight documentation to include data
archive searches may be obtained from the following:

Airborne Sensor Facility

MS 240-6

NASA Ames Research Center

Moffett Field, CA 94035-1000

Telephone: (650)604-6252 (FAX 4987)