Thursday, May 14, 2009

Environmental Mapping and Analysis Program

The Environmental Mapping and Analysis Program (EnMAP) is a German hyperspectral mission, scheduled for launch in 2012. The primary goal of EnMAP is to offer accurate, diagnostic information on the state and evolution of terrestrial ecosystems on a timely and frequent basis, and to allow for a detailed analysis of surface parameters with regard to the characterization of vegetation canopies, rock/soil targets and coastal waters on a global scale. EnMAP is designed to record bio-physical, bio-chemical and geo-chemical variables to increase our understanding of biospheric /geospheric processes and to ensure the sustainability of our resources.

EnMAP will monitor the Earth's surface with a ground sampling distance (GSD) of 30 m x 30 m (30 km x 5000 km per day) measuring in the 420-2450 nm range by means of two separate spectrometers covering the visible to near-infrared (VNIR) and short-wave infrared (SWIR) spectral regions with 250 contiguous bands. The mean spectral sampling distance and resolution is of 6.5 nm at the VNIR, and of 10 nm at the SWIR. Accurate radiometric and spectral responses are guaranteed by a defined signal-to-noise ratio (SNR) of ≥ 500:1 in the VNIR and ≥ 150:1 in the SWIR, a radiometric calibration accuracy better than 5% and a spectral calibration uncertainty of 0.5 in the VNIR and 1 nm in the SWIR. An off-nadir pointing capability of up to 30° enables a target revisit time of 4 days.

In this program the GFZ Potsdam has the scientific lead, Kayser-Threde is the industrial prime and OHB Systems provides the bus. The German Space Agency is managing the project and the German Aerospace Establishment is responsible for the ground segment.

EnMAP - Requirements and Technical Outline
Multi- versus Hyperspectral / Potentials

Every material is formed by chemical bonds, and as such can be characterised by spectral absorption features in the electromagnetic spectrum. EnMAP has the capability to detect individual absorption features in the spectra of many materials, solids, liquids, or gases. Actual detection depends on the instrument´s spectral coverage, spectral resolution, spectral sampling, signal-to-noise ratio, the abundance of the material and the strength of the materials absorption features in the wavelength region measured.

Spectral Requirements

Spectral sampling interval

420 nm - 1000 nm ----- 5 nm

900 nm - 1390 nm ----- 10 nm
1480 nm - 1760 nm ----- 10 nm
1950 nm - 2450 nm ----- 10 nm

Spectral bandwidth (FWHM)
420 nm - 1000 nm ----- 5 ± 1.0 nm

900 nm - 1390 nm ----- 10 ± 1.5 nm
1480 nm - 1760 nm ----- 10 ± 1.5 nm
1950 nm - 2450 nm ----- 10 ± 1.5 nm

The Number of bands may vary due to overlap at 900-1000nm and non-linearities of prism design.


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