Experimental studies of electrical noise in the aircraft control system

Currently, the problem of reducing noise in electrical equipment is important, because a noise in the system affects its components and can cause unpredictable behavior of the electrical system. This is especially important onboard of unmanned aerial vehicle (UAV), where all components are located close to each other and their noise has a significant cross-effect. Conductors passing through a noisy environment can pick up a noise and direct it to another circuits, where it creates interference. Some examples of such noise problems are: degraded accuracy characteristics of microcontroller modules (Analog-to-Digital Converters (ADC), Phase-Locked Loops (PLL) and other) due to noise on supply and reference voltages, wrong acquisition of the digital signals and interference with global navigation satellite system (GNSS) or remote control system of UAV. This article is dedicated to the research of the influence of electrical noise, which is formed by the components of the UAV control system (engines, electric motor controllers, microcontroller etc.), on the performance and noise protection of electronic components of the UAV control system. After the research it was concluded that the main sources of elecrtrical noise in the UAV control system are: high currents, consumed by electronic speed controllers (with motors), high-speed toggling of clock signal of SPI / I2C communication, regulation by step-down voltage regulator and internal processes inside the microcontroller due to work of flight control firmware. The waveforms of generated noises, caused by each source was measured with oscilloscope and depicted in the article.