For the problem of low altitude target tracking with acoustic wireless network, the signal propagation time delay effect must be considered. The target has been far away from its emitting position when the signal is received by sensors. This effect leads to synchronous sensors in the measurement space sample asynchronously in the state space and the sample frequency becomes unknown and time varying. In this paper, a batch type distribution fusion algorithm is proposed which consists of two steps. First, a linear search method is used for estimating the time-varying state transition time which is the parameter of least square solution for the initial state. This initial state is used again to optimize the state transition time until the iteration termination condition is satisfied. Second, a time register procedure and a distribution fusion technique are presented to obtain the global track. Simulation results verify the efficiency of the proposed method.