Due to the dynamic growth of applying civilian and military unmanned aerial platforms, a large saturation of the airspace with this type of objects is observed. There are many problems associated with this, among which there are the following: lack of systems informing about the location of other flying objects and violations of protected areas by unauthorized flying platforms. In this paper the concept of direction finding and localization of radio emissions using the Unmanned Aerial Vehicles based on the idea of a hierarchical “swarm” is presented. It is also discussed the UAV detection methods taking into account the specific features of detected radio signal and selected aspects related to the functioning of UAS. Geolocation techniques are presented and one of them, dedicated to direction finding sources of radio emissions, is indicated as preferred. Additionally, relevant mathematical formulas for geolocation method are proposed.
FH emissions are currently used in many wireless communication systems, where military communication is a special area of their application. The use of such emissions reduces the likelihood of detection and interception of transmission and increases their resistance to jamming. The larger is the set of carrier frequencies, the more FH emission is dispersed and harder to detect and disrupt. Currently used frequency allocation algorithm does not allow sharing of available frequencies in the same area. For this reason, the number of assigned frequencies for individual network drops significantly, reducing all the advantages of FH emissions. In this paper an effective way to use frequency resources to increase the capacity of the transmission channel assuming a certain number of radio networks or the certain number of available carrier frequencies is proposed. The basic assumption is the possibility of simultaneous operation of many FH radio networks in the same territorial area, on a common frequency set. At a certain probability of collision, the dependence of the number of radio networks which worked simultaneously, from the cardinality of a common set of carrier frequencies and the influence of the number of frequencies on this probability is considered. The results of the analysis of the number of collisions between different FH networks working simultaneously in the same area with an identical set of carrier frequencies are also presented. Relevant mathematical formulas are proposed for different collision scenarios that can be used in the frequency assignment process. The results are verified in practice with the use of VHF radios.