In the atmosphere, a huge spectrum of signals for various services is very often transmitted wirelessly. Let's mention radio and TV modulation, data transmission, wireless telephony, internet, signal for mobile phones, navigation signals and many other services. This brings requirements for the description of the degradation effects of the atmosphere, which cause mainly:
- Signal attenuation
- Signal depolarization
- Signal phase delay
- Signal trajectory change
Significant atmospheric degradation is caused by hydrometeors (rain, hail, snow, ice crystals,…), fog, clouds, melting layer, air humidity on one hand, but also by wind on the other hand. The ionosphere also significantly affects the propagation of waves, but it can be used for the desired signal reflection.
At IAP, we are intensively focusing on the analysis and statistics of degradation effects of atmosphere on propagating signals, especially on their attenuation in atmosphere. We focus mostly on rain research, which is the most important degrading factor for radio links in our climate. On the other hand, for optical wireless links, we deal with the analysis of fog and clouds. This represents the acquisition of a physical description of the scattering of waves on raindrops or fog droplets and their clump. We must know, for example, the shape of drops, which we measure by distrometer. Other research tools include meteorological radar, rain gauge, humidity sensor, ceilometer, anemometer etc., etc. The results of our research serve as a basis for rational planning of wireless links.