In the recent decade, there has been an exponential rise in the development and use of unmanned aerial vehicles in various industries. Inaccessible control, load capability, imagination, target, and secrecy drove the interest in unmanned aerial vehicles for various applications. UAVs' navigation and communication systems are becoming vulnerable to multiple security issues. The most serious concern about security threats emanates from GNSS systems; spoofing and jamming are common. In this paper, we have made an in-depth analysis using selected and recent peer-reviewed journals that seek to secure UAV navigation. Analyze. The gaps were addressed and summarized considering the root cause of GNSS-related challenges and promising research directions in the field of UAV navigation security.