In this paper, we summarize the results of inertial navigation-based integrated navigation systems that have been researched for over 30 years. First, we introduce the core technologies for operating inertial navigation systems (INS) and discuss the technological advances in pedestrian navigation using small and low-cost inertial sensors for mobile devices. Second, we present the integrated navigation systems with other sensors to overcome the limitations of the INS, which degrades over time. The fundamental principles of, and major research on the inertial-based integrated navigation system with global navigation satellite system, database, or camera/LiDAR are discussed. Finally, the major achievements in recent advances in artificial intelligence-assisted navigation are addressed.