Experimental Study On Underwater Positioning System Active Electric Field Characteristics

Active underwater electrolocation is a new navigation technology that achieves underwater terminal navigation through launching low-frequency electric field. The mechanism of active electrolocation makes it unsensitive to the water turbidity. Launching low-frequency electric field makes the hardware of the system simple. Active underwater electrolocation overcomes the disadvantages of the existing underwater location technology such as high hardware requirements for underwater sonar and location difficulties and shortcomings in the turbid environment of underwater visual navigation.This paper follows the order from low frequency to high frequency in accordance with the frequency domain, from the direct current excitation to dual-frequency excitation. There are a series of experimental studies on features of active underwater electrolocation system, including the research on detection electrodes, the research on electric field detection region, the research on location strategies as well as the detection of different attributes of objects. Through experimental studies of active electric field location features, the following main conclusions are drawn:1. The electric field intensity of infield area between launching electrodes is stable. So it is more suitable for use as the probe electric field than the outer field region. While among the outer field regions, the effect of active electric field location in the anode outside field is better than that in the cathode outside field.2. In electrostatic field detection, hysteresis phenomenon appears between positive and negative process curves. The hysteresis phenomenon relates to the resistance of the object to be detected. Hysteresis responses are different between metal conductors and insulators.3. In sinusoidal electric field detection, there is no hysteresis phenomenon between positive and negative process curves. Metal conductors and insulators detection of sinusoidal electric field response in different ways:the probe electric field detected is weakened by metal conductor while enhanced by insulator.4. The square wave electric field detection has both experimental characteristics of direct current excitation and sinusoidal signal excitation. The results of square wave electric field detection on different resistance targets have differences not only in hysteresis phenomenon, but also in energy changes of the probe electric field.5. In induced polarization method, active underwater electrolocation can be achieved separately by high-frequency component and low-frequency component. The responses of conductors, semiconductors and insulators are not the same. Therefore, it is necessary to determine the electric field frequency and the rate of high-frequency to low-frequency according to the capacitive characteristics of the target object. So that obvious frequency response differences can be got.