Matches in climatepub4-kg for { <http://example.org/resource/22dc2a25-e81e-4408-bcf2-a47ef28d7f7f> ?p ?o ?g. }
Showing items 1 to 15 of
15
with 100 items per page.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f definition "The Visible and Near Infrared Radiometer (VNIR) is one of ASTER's three different subsystems. The VNIR subsystem consists of two independent telescope assemblies to minimize image distortion in the backward and nadir looking telescopes. The detectors for each of the bands consist of 5000 element silicon charge coupled detectors (CCD's). Only 4000 of these detectors are used at any one time. A time lag occurs between the acquisition of the backward image and the nadir image. During this time earth rotation displaces the image center. The VNIR subsystem automatically extracts the correct 4000 pixels based on orbit position information supplied by the EOS platform. The VNIR optical system is a reflecting-refracting improved Schmidt design. The backward looking telescope focal plane contains only a single detector array and uses an interference filter for wavelength discrimination. The focal plane of the nadir telescope contains 3 line arrays and uses a dichroic prism and interference filters for spectral separation allowing all three bands to view the same area simultaneously. The telescope and detectors are maintained at 296 + 3K using thermal control and cooling from a platform provided cold plate. On-board calibration of the two VNIR telescopes is accomplished with either of two independent calibration devices for each telescope. The radiation source is a halogen lamp. A diverging beam from the lamp filament is input to the first optical element (Schmidt corrector) of the telescope subsystem filling part of the aperture. The detector elements are uniformly irradiated by this beam. In each calibration device, two silicon photo-diodes are used to monitor the radiance of the lamp. One photo-diode monitors the filament directly and the second monitors the calibration beam just in front of the first optical element of the telescope. The temperature of the lamp base and the photo-diodes is also monitored. Provision for electrical calibration of the electronic components is also provided. The system signal-to-noise is controlled by specifying the NE delta rho to be < 0.5% referenced to a diffuse target with a 70% albedo at the equator during equinox. The absolute radiometric accuracy is to be + 4% or better. The VNIR subsystem produces by far the highest data rate of the three ASTER imaging subsystems. With all four bands operating (3 nadir and 1 backward) the data rate including image data, supplemental information and subsystem engineering data is 62 Mbps. [Summary provided by NASA] Group: Instrument_Details Entry_ID: VNIR Group: Instrument_Identification Instrument_Category: Earth Remote Sensing Instruments Instrument_Class: Passive Remote Sensing Instrument_Type: Spectrometers/Radiometers Instrument_Subtype: Imaging Spectrometers/Radiometers Short_Name: VNIR Long_Name: Visible and Near Infrared Radiometer End_Group End_Group" @default.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f id "1654367" @default.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f path_id 2e38423f-a5e6-411a-88d3-8fdc00aaf30a @default.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f path_id 4f81c61c-f100-4bc4-9664-d9b70d2f162f @default.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f path_id 6015ef7b-f3bd-49e1-9193-cc23db566b69 @default.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f path_id 944b7691-af37-4fb4-9393-c114e7997829 @default.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f path_id b2140059-b3ca-415c-b0a7-3e142783ffe8 @default.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f path_label "Earth Remote Sensing Instruments" @default.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f path_label "Imaging Spectrometers/Radiometers" @default.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f path_label "Instruments" @default.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f path_label "Passive Remote Sensing" @default.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f path_label "Spectrometers/Radiometers" @default.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f prefLabel "VNIR" @default.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f reference "" @default.
- 22dc2a25-e81e-4408-bcf2-a47ef28d7f7f tag "Instruments" @default.