Design of electrostatic direction-finding system based on FPGA

Any objects using an engine or moving objects will be charged because of a variety of different charging processes. It is possible to sense the object and its moving direction by measuring the electrostatic field around the object. In this paper, an electrostatic direction-finding system based on FPGA is designed to detect the direction of the charged moving object in real time. The system is composed of the electrostatic detection electrode array, current detecting electrostatic detection circuit and digital signal processing circuit based on FPGA. To meet the requirements of high input impedance and high sensitivity of the electrostatic signal detection circuit, the first and second stage amplifier circuits based on FET and operational amplifier were designed. According to the principle of electrostatic direction-finding, an electrostatic sensor calibration system was designed to calibrate the electrostatic sensors in the electrostatic direction-finding array, which insures the consistency of the electrostatic detection array and improves the direction-finding accuracy. The signal processor based on FPGA was designed according the performance parameters of the electrostatic direction-finding system, which achieves the signal acquisition and processing of the electrostatic sensors and the direction real time solution of the charged moving object. The experiment result shows that the direction angle error of the charged moving object using this system is less than 15° and the system meets the real-time solution requirements in certain extent.