This project aims to address the increasing drone safety risks by developing redundant sensing with an integrated multi-sensor system to ensure drone Positioning, Navigation, and Timing (PNT) in various conditions. As GNSS becomes more vulnerable, there is a need for more resistant and robust drone PNT, which would maintain the accuracy even in the absence of GNSS. We will develop a high-performance sensor solution for drone PNT with integrity and reliability guarantees. The solution will be based on sensor arrays, advanced sensor fusion, and integrity monitoring for enhanced PNT redundance and accuracy. The sensor fusion approach will also be utilized for situational awareness and collision avoidance. The performance of the system will be validated with simulations and field tests.