In multi-sensor systems, time synchronization between sensors is a significant challenge, and this issue is particularly pronounced in underwater integrated navigation systems incorporating acoustic positioning. Such systems are highly susceptible to time delay, which can significantly degrade accuracy when measurement and fusion moments are misaligned. To address this challenge, this paper introduces a tightly coupled navigation framework that integrates a passive inverted ultra-short baseline (piUSBL) acoustic positioning system, a strapdown inertial navigation system (SINS), and a depth gauge under precise time synchronization. The framework fuses azimuth and slant range from the piUSBL with depth data, thereby avoiding poor vertical-angle observability in planar arrays. A novel delay measurement strategy is introduced, combining synchronized timing with acoustic signal processing, which redefines delay-traditionally an unobservable error-into a quantifiable parameter, enabling explicit estimation of both acoustic propagation and system processing delays. Simulations and field experiments confirm the feasibility of the proposed method, with delay-compensated navigation reducing RMSE by 40.45% and maximum error by 32.55%. These findings show that precise delay measurement and compensation not only enhance underwater navigation accuracy but also establish a generalizable framework for acoustic positioning integration, offering valuable insights into time alignment and data fusion in latency-sensitive multi-sensor systems.

翻译：在多传感器系统中，传感器间的时间同步是一项重大挑战，这一问题在包含声学定位的水下组合导航系统中尤为突出。此类系统极易受到时延影响，当测量与融合时刻未对齐时，其精度会显著下降。为应对这一挑战，本文提出一种在精密时间同步下集成无源倒置超短基线声学定位系统、捷联惯性导航系统与深度计的紧耦合导航框架。该框架将来自piUSBL的方位角、斜距与深度数据相融合，从而避免了平面阵列中垂直角可观测性差的问题。本文引入一种新颖的时延测量策略，将同步定时与声学信号处理相结合，将传统上不可观测的时延误差重新定义为可量化参数，实现了对声学传播时延与系统处理时延的显式估计。仿真与现场实验验证了所提方法的可行性，经时延补偿后的导航结果使均方根误差降低了40.45%，最大误差降低了32.55%。这些结果表明，精密时延测量与补偿不仅能提升水下导航精度，还为声学定位集成建立了一个可推广的框架，为时延敏感的多传感器系统中的时间对准与数据融合提供了有价值的见解。