Analytical Modeling and Simulation for Investigation of a Digital Gas Filter Correlation Radiometer

This thesis investigates a digital gas filter correlation radiometer called the Tropospheric Radiometer for Atmospheric Chemistry and Environmental Research (TRACER), which will be used to remotely measure carbon monoxide at three levels in the troposphere. The nadir-viewing radiometer measures the differential absorption of radiation through the atmosphere at 4.67@m and 2.33pm wavelengths. This thesis develops an analytical model of the TRACER measurement process to evaluate the effect of varying certain system parameters on the measurement. The independent sampling criterion and the response of linear systems to random signals are explained. A parametric simulation model is also developed to evaluate the analytical model. The inputs to the model are the expected radiation onto the detectors at 4.67p.m and 2.33pm calculated from previous atmospheric studies. The detector, preamplifier, analog-to-digital converter, and pulse averaging strategy are described in detail. The varied parameters are preamplifier cutoff frequency, quantization length, and sampling frequency.