Realization of a noise immunity algorithm for detecting obstacles on the trajectory of unmanned aerial vehicles

The problematic of the control system of an unmanned aerial vehicle associated with the detection of obstacles on the trajectory of motion is considered. A solution is proposed in the form of a radio-frequency engineering device that allows working under fog and dust conditions. The structure of a radio-frequency engineering device is developed that implements a noise immunity algorithm for processing a useful signal. The algorithm is based on comparing the amplitudes of the harmonics of the difference frequency signal. The use of linear frequency modulation in the probing signal makes it possible to form a high-steep range selection function. When the algorithm is implemented, subsampling is used, which makes it possible to reduce the effect of the leakage signal and reduce the requirements for the conversion frequency of the analog-to- digital converter. For synchronization of both modulating voltage and clock signal of analog-to-digital converter an internal oscillator of microcontroller with phase-locked loop is used. The possibility of regulating the operating range by changing the amplitude of the modulation voltage is shown. A sample of a radio-frequency engineering device was developed. Small dimensions make it possible to use the device with almost all modern unmanned aerial vehicles. Working capacity of the sample is checked. The influence of noise at the input of the receiver on the characteristics of the system is explored. Based on the obtained results, a conclusion is made about the operability and high noise immunity of the device. Recommendations for designing of such a radio-frequency engineering device are given.