\r\n\r\n
The NERC Airborne Research and Survey Facility (ARSF) has flown two ATM instruments over the period 1982 - present: the Daedalus 1268 was operated from 1982 until 1998. Since 1996 an upgraded version - the Azimuth Systems AZ-16 has been used, along with an improved data acquisition system.
\r\nThe eleven spectral channels of these instruments cover the visible and near-infrared (Chs: 1-8), shortwave infrared (SWIR - Chs: 9 & 10) and thermal infrared (TIR - Ch: 11) many of which closely match the seven channels of the Landsat Thematic Mapper satellite (see Fig.1 and Table 1):
\r\n| ATM Band | \r\nSpectral range (μ m) | \r\nEquivalent Landsat TM band |
|---|---|---|
| 1 | \r\n0.42 - 0.45 | \r\n|
| 2 | \r\n0.45 - 0.52 | \r\n1 |
| 3 | \r\n0.52 - 0.60 | \r\n2 |
| 4 | \r\n0.605 - 0.625 | \r\n|
| 5 | \r\n0.63 - 0.69 | \r\n3 |
| 6 | \r\n0.695 - 0.75 | \r\n|
| 7 | \r\n0.76 - 0.90 | \r\n4 |
| 8 | \r\n0.91 - 1.05 | \r\n|
| 9 | \r\n1.55 - 1.75 | \r\n5 |
| 10 | \r\n2.08 - 2.35 | \r\n7 |
| 11 | \r\n8.5 - 13.0# | \r\n6 |
| 12 | \r\nSpare thermal channel | \r\n
Table 1. Band characteristics of the Daedalus 1268 Airborne Thematic Mapper instrument compared to those of the Landsat Thematic Mapper instrument. [# Thermal band broadened for aircraft operation.]
\r\n![](\"http://www.neodc.rl.ac.uk/images/data_pages/ATM_landsat_smaller.jpg\")
Figure 1. Comparison of ATM and LANDSAT-7 bands in the visible and near-infrared spectrum. ATM band 11 (not shown) is in the thermal infrared region, spanning 8400-11500 nm. Landsat-7 Band 8 (not shown) is a panchromatic band spanning the region 520-900 nm.
\r\nComparative Specifications of the Airborne Thematic Mapper - in its Daedalus 1268 and AZ-16 configurations?are provided in Table 2, below:
\r\n| \r\n | Daedalus 1268 | \r\nAZ-16 |
|---|---|---|
| Operational period | \r\n1982-1985 \r\n | 1996-present | \r\n
| IFOV | \r\n2.5 mrad | \r\n2.5 mrad |
| Pixel swath | \r\n716 | \r\n992/1984 |
| Digitised FOV | \r\n86 ° | \r\n90 ° |
| S-bend correction | \r\n73 ° | \r\n|
| Scan rate | \r\n12.5, 25, 50 Hz | \r\n12.5, 25, 50 Hz |
| Roll correction | \r\n+/-15 ° | \r\n|
| Resolution | \r\n8-bit (0-255) | \r\n16-bit (0-65535) |
| Thermal channel calibration | \r\nTwo black bodies |
Table 2. Comparison of Daedalus 1268 and AZ-16 systems.
\r\nA fully automated Integrated Data System (IDS) was commissioned in late 1998/early 1999 and can now routinely provide geometrically registered, radiometrically calibrated data for both the multi-spectral ATM and the hyper-spectral CASI systems as operated by the NERC Airborne Research and Survey Facility.