Calibration Capabilities

All remote sensing sensors receive electromagnetic radiation. The sensor then converts the radiation into an electronic signal. However, an electronic signal is meaningless unless it is related to a physical unit. Simply speaking, calibration of a remote sensing sensor is the procedure to establish the conversion parameter that translates output of the sensor to a measurable physical unit.

For example, the output reading of a spectroradiometer has the units of radiance at a specifically measured wavelength. The spectroradiometer must be properly calibrated in radiance, irradiance, and wavelength .

In the case of an airborne imaging spectrometer, the sensor measures not only the radiance but also the spatial aspects of the image. Calibration requires characterization of the spatial resolving and positioning capability of the instrument. Other calibrations may be required due to specific optical system used. (e.g. whisk broom scanning, push broom scanning, single-facet scanning, or multi-facet scanning optics, etc.)

Spectra Vista Corporation maintains a fully equipped optical laboratory for complete calibration and characterization of all Spectra Vista or GER produced sensors.

The following is a list of calibrations performed on our products.

Field Portable Spectroradiometers

1. Wavelength calibration: All field spectrometers are calibrated to its published specification. Equipment most often used in this calibrations include: fully automated monochrometer, spectral line source (e.g. Argon, Mercury, Krypton, etc.), narrow band filters and other known band targets.
   Proprietary software is used to generate calibration parameters from all calibration measurements.


2. Radiometric calibration: All field portable spectrometers are calibrated by NIST traceable, automated integrating sphere calibration standard (Optronic Laboratories, Inc., OL Series 462).


3. Field of View calibration: The optical field of view for a field portable spectrometer determines what is being measured. All field spectrometers are calibrated to give a clearly defined field of view.

Airborne Systems

1. Wavelength calibration: Calibration is done by proprietary Windows-based software. This software controls the scanning of each detector/band with a narrow band signal from a monochrometer. Hundreds of bands can be done automatically without human intervention. Full report of spectral response curves is generated automatically.


2. Radiometric Calibration: A NIST traceable, automated integrating sphere calibration standard (Optronic Laboratories, Inc., OL Series 462), is used at the system focal point for this work. Proprietary software is used.


3. Spatial calibration: Precision spatial targets are used at the system focal point for this work. System MTF (Modulation Transfer Function) can be calculated. Proprietary software is used.


4. Other system characterizations: Signal to Noise Ratio (SNR), Noise Equivalent Radiance (NER), Noise Equivalent Temperature Difference (NEDT, for thermal sensor), electronic linearity and bandwidth, and many other system characters can be provided.

SVC, GER 1500, GER 2600, GER 3700, spectrometer, multispectral, hyperspectral, remote sensing equipment, recalibration, instruments, GER Millbrook, NY, Geophysical and Evironmental Research Corporation