Active Sonar Time Window Navigation and Positioning Model Without Appending External Navigation Information

Objectives： Due to the inherent difficulty of time synchronization of submarine navigation beacons, underwater navigation usually adopts an active positioning model. However, the model is always ill-defined, that is, each observation corresponds to two waiting points at which the carrier signal is sent and received. When the carrier motion is ignored, half of the signal round-trip travel time can be used as the observed value to locate the signal, but this will inevitably introduce model errors, especially in deepsea scenes or high-speed carrier motion. If the use of Doppler velocity measurement or inertial navigation and other dead reckoning information, it will lead to sonar navigation dependent on external information, but no longer independent. Methods: In this paper, a time-window navigation and positioning model with additional carrier kinematic parameters is proposed to realize the joint estimation of carrier position, velocity, acceleration and other information, which can not only output the carrier's current moment coordinates, but also obtain the carrier's motion information at any time, such as the carrier's position, velocity and acceleration at the middle of the window. Results: The problem of the inadequacy of the active positioning model is solved effectively. At the same time, the concept of geometric factor (KDOP) is proposed to evaluate the geometric strength of time-windowed navigation. The results show that the KDOP proposed in this paper can well describe the advantages and disadvantages of the time-windowed navigation and positioning configuration, and the time-windowed navigation and positioning model is significantly superior to the traditional spatial intersection positioning model. Conclusions: The test results on the Japanese public data set show that the navigation and positioning accuracy proposed in this paper is better than 5m, and the positioning accuracy at the middle time of the window is higher.