Instrument

Instrument Model

The instrument model transforms radiance at the front aperature into the digital signals produced by the electronics. These signals are then calibrated to generated synthetic measurements. The overall flow of information through the ALI instrument model is shown in Fig. 1.

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Fig. 1 Overview of the instrument software design.

The instrument is composed of four main modules:

  1. Optics Applies transformations from the liquid crystal rotator, polarizers, and AOTF.

  2. Sensor Integrates the post-optics radiance both spatially and spectrally onto the sensor pixels.

  3. Electronics Transforms the integrated radiance into the level 0 signal.

  4. Calibration Applies transmission and electronics properties to convert the level 0 signal into level 1 data.

Forward Model

The ImagingSimulator is used to produce level 1 data and is the primary interface to the Rodgers retrieval. Unlike an Instrument class which simply transforms radiance, the ImagingSimulator generates a set of level 1 data given an atmospheric state, a geometry and an instrument.