A New Triangulation-Like Technique for the Evaluation of the Refractive Index Structure Constant $(C_{n}^{2})$ in Free-Space Optical Links

Measurements of indoor/outdoor atmospheric turbulence through optical triangulation method

“…In the original [14] experiment, we tracked the optical beam using a plane containing three photodetectors in order to calculate the hotspot position and a fourth photodetector, in the center, to measure the central power of the optical beam P c ( ) and to help in the system alignment. At that time [14], in order to test if the device could track the hotspot, it was decided to shift the plane to perform the relative displacement of the beam. With the screen 21 cm away from the source, it was found that the device could track the hotspot and consequently was able to evaluate the atmospheric turbulence.…”

“…In 2009, Silva et al published an article [14] describing a device that measures the beam wander effect by tracking the beam at a distance of 21 cm between the transmitter and the receiver. Later, in 2016, further workbench experiments were done and it has been proved, by using a set of lenses, that the device can also measure the beam spread effect [15].…”

“…Thus, this work aims to characterize the real outdoor atmospheric turbulence between two buildings by tracking the beam and measuring the beam spread, which was not done in [14]. It is important to note that some necessary and essential modifications had to be made to the original device in order to be able to realize the new measurements.…”

Novo Método de Medida de Evaporação e Evapotranspiração para Áreas de Plantio

“…Assim, resolvendo o sistema de equações com as distâncias ri, onde r i = √(x i − x 0 ) 2 + (y i − y 0 ) 2 , pode-se calcular a posição (x0,y0), que é o centro da projeção do feixe gaussiano [7]:…”

“…Nesse caso, são observadas variações aleatórias na posição do feixe óptico no receptor. Assim, rastreando o feixe por meio da Técnica de Triangulação de Potências Ópticas consegue-se inferir e quantificar a turbulência atmosférica [6][7][8][9].…”