TECHNIQUE OF DETECTION RANGE ESTIMATING FOR UNMANNED AERIAL VEHICLES BASED ON THEIR 3D MODELS

The problem of unmanned aerial vehicles (UAVs) detection and ranging is considered. It is shown that due to the small geometrical dimensions, the use of composite materials, low engine power and low flight altitudes, the UAVs are practically undetectable for long distances in thermal, radio and acoustic ranges, thus, the main detection range for UAVs is visible. The effectiveness of visual detection mainly depends on three factors: the background brightness, the contrast of the object with the background and the angular size of the object. For the most favorable observation conditions, the maximum detection range is determined by the angular size of the object. In the case of observation with the naked eye, the maximum detection range corresponds to the angular size of the object at one angular minute. Based on this condition the technique for visual detection range indicatrice constructing is proposed. It presumes obtaining visually observable for given azimuth and elevation angles UAV’s square calculated in CAD system for existing 3D model of UAV. The technique was successfully tested on UAV models with different aerodynamic schemes. The influence of the aerodynamic scheme on the detection range is analyzed. It is shown that the models constructed according to the "flying wing" scheme have a detection range that is practically independent of the azimuth, and the models constructed according to the normal scheme are detected at a greater distance in the lateral observation than when viewed from the front. The indicatrices of the detection range for one of the UAV models obtained from the experimental data and data modeled by the proposed technique are compared. It is shown that, in general, the technique provides values of the detection range close to the experimental data, but a bit higher. This confirms the applicability of the technique for providing comparative analysis of various models of UAVs. For obtaining more accurate detection range estimation results the further improvement of the technique is necessary. The main approaches of further work in this direction are outlined. They concern the exclusion of the areas of the UAV’s elements, which have a hidden color and specific elongated shape