In multisensor systems, time synchronization is particularly challenging for underwater integrated navigation systems (INSs) incorporating acoustic positioning, where time delays can significantly degrade accuracy when measurement and fusion epochs are misaligned. This article introduces a tightly coupled navigation framework that integrates a passive inverted ultrashort baseline (piUSBL) acoustic positioning system, a strapdown inertial navigation system (SINS), and a depth gauge under precise time synchronization. The framework fuses piUSBL azimuth and slant range with depth measurements, avoiding poor vertical-angle observability in planar arrays. By combining synchronized timing with acoustic signal processing, the proposed method transforms delay from an unobservable error into a measurable parameter, enabling explicit quantification of both acoustic propagation and system processing delays. Field experiments demonstrate that the proposed approach reduces position RMSE by 44.02% and maximum error (MAXERR) by 40.79% compared to the uncompensated baseline while achieving further RMSE reductions of 37.66% and 35.82% in horizontal directions relative to filter-based delay compensation. The results confirm that explicit delay measurement outperforms filter-based estimation though instantaneous performance remains sensitive to acoustic signal quality, emphasizing the need for robust signal processing alongside accurate time synchronization in latency-sensitive multisensor systems.

翻译：在多传感器系统中，时间同步对于融合声学定位的水下组合导航系统（INSs）尤为困难——当测量与融合历元错位时，时延会显著降低精度。本文提出一种紧耦合导航框架，在精确时间同步条件下集成被动倒置超短基线（piUSBL）声学定位系统、捷联惯性导航系统（SINS）和深度计。该框架融合piUSBL方位角、斜距与深度测量值，避免了平面阵列中垂直角可观测性差的问题。通过将时间同步与声学信号处理相结合，所提方法将时延从不可观测误差转化为可测量参数，实现了声学传播延迟与系统处理延迟的显式量化。现场实验表明，与未补偿基线相比，该方法将位置均方根误差（RMSE）降低44.02%，最大误差（MAXERR）降低40.79%；同时，相较于基于滤波器的时延补偿方法，水平方向RMSE进一步降低37.66%和35.82%。实验结果证实，尽管瞬时性能仍对声学信号质量敏感，但显式时延测量优于基于滤波器的估计——这凸显了在延迟敏感的多传感器系统中，稳健信号处理与精确时间同步同等重要。