Doppler-sonar is a dead-reckoning system . 多普勒-声纳是一种推测航位系统。
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Fundamentally an inertial navigation system is a dead-reckoning system with a very significant characteristic which differentiates it from more conventional dead-reckoning equipment . 原则上惯性导航系统是一种航行推算系统,与一般的航行推算装置不同,它具有极明显的特点。