Single-Source Aided Semi-Autonomous Passive Location for Correcting the Position of an Underwater Vehicle

The accumulated positioning errors are required to be eliminated after a long run-up of an underwater vehicle equipped with an inertial navigation system (INS). For the better position accuracy with less cost, a single-source aided passive location method is proposed, which applies acoustic positioning together with inertial navigation. The fixed sound source periodically emits the acoustic wave pulse under water. After a number of signals are received, a high-precision synthetic array is built with the positions measured by inertial instruments and clock on board. Then, the source is located by time-difference-of-arrival positioning technology and the navigation error of the moving vehicle is reduced. Different from fully autonomous, there is a radiation source and sound is provided as intermediary locally. It is independent of the control and the algorithm. The operation and calculation are performed on the vehicle, so it is called semi-autonomous. Multiple users are supported simultaneously. Since no radiation is sent from the vehicle, it is extremely concealed. More importantly, it is inexpensive and the accuracy has nothing to do with the amount of error before. In the simulation, the position error could be suppressed to 50 m or less. The results show that the new approach for underwater positioning is effective and reliable. After a period of time, INS error can be eliminated quickly when the vehicle returns to the correction area within the range of the single-source. In this way, long-time and accurate navigation is realized underwater.