A new atmospheric refractivity meter

Abstract

The present paper describes a simple electronic system employing a hybrid technique for digital measurements of the atmospheric refractivity. The technique is based on processing the sensed analogue signals from temperature, humidity and pressure sensors in order to realize the following relation by hardware

where N is the refractivity, h is the relative humidity, P is the pressure in mb and T _c, T _k are the temperatures in ^°C, ^°K respectively. Using simulated signals, the system was checked and a system accuracy of better than 1% was obtained over ranges of T _c(−10–50^° C), h(0–100%), and P(800–1100mb). This accuracy is thought to be quite satisfactory for line of sight communication system applications and lies within the chosen sensors accuracy.