Vågutbredningsanalys för UAV-stöd i taktiska mobila radionät

The work consists of two parts, one part evaluating possible ranges in a battalion network supported by autonomous UAVs and the second part describing new measurement results for link attenuation in forest for GHz frequencies. A network consisting of autonomous low-flying UAVs can use higher frequencies than todays tactical radio networks because the links between the UAVs are above the difficult terrain. Such solutions provides the opportunity to increase the capacity in the network, if the attenuation of the signal through vegetation between UAVs and ground vehicles not become too large. Therefore, we analyze the wave propagation between a ground vehicle in forest terrain and a UAV. The results show large differences in link loss depending on frequency bands and forest density. The calculations show that the transmission loss between ground vehicles and an UAV is low enough for our system examples at frequencies up to 1500-2500 MHz, but for 2500 MHz, directional antennas and higher UAV heights are required. Our measurement method for forest attenuation utilizes satellite navigation systems signals, is therefore simple, and can be performed without expensive equipment. The measurement results provides lower attenuation in forest than the ITU model that we compare with.