Robust navigation is becoming a critical challenge as positioning systems operate in increasingly complex, contested, and non-ideal environments. This special session focuses on advanced robust estimation and signal processing techniques for navigation under model mismatch, non-Gaussian noise, multipath, interference, and faulty measurements. Topics include robust statistics, fault detection and exclusion, outlier mitigation, non-Gaussian filtering, integrity monitoring, and resilient estimation against GNSS threats. The session aims to gather researchers and practitioners developing theoretical advances and practical solutions to improve the reliability, integrity, and resilience of next-generation navigation systems.