Autonomous Integrity of Multisource Information Resilient Fusion Navigation System: State-of-the-Art and Open Challenges

National positioning, navigation, and timing (PNT) has evolved into a national strategy in many countries and is currently undergoing project initiation and construction. The keys to comprehensive PNT are secure, continuous, and reliable applications. Resilient fusion of multisource information is an effective means for achieving comprehensive PNT. The autonomous integrity of resilient PNT for user terminal serves as a safeguard for the secure, continuous, and reliable applications in comprehensive PNT. Currently, there are several integrity monitoring technologies and theories for individual systems, as well as some preliminary explorations into autonomous integrity monitoring methods for multisource information fusion scenarios. However, these technical architectures and theoretical methods are still insufficient to meet the security, continuity, and reliability requirements of comprehensive PNT. Therefore, this article proposes a novel autonomous integrity monitoring framework for the resilient fusion of multisource information, reviews the current development status of autonomous integrity monitoring for multisource fusion navigation systems, and points out the challenging issues that exist.