Unmanned Aerial Vehicles (UAVs) face distinct security challenges due to their distributed nature and vulnerability to evolving threats. Traditional IDS often fall short in addressing real-time and zero-day attacks in these environments, highlighting the need for specialized solutions. This chapter introduces a Unified Intrusion Detection System (UIDS) designed to enhance UAV security using a Lightweight Multi-tier IDS architecture. The proposed framework deploys multiple detection units across UAV networks, improving detection accuracy while conserving resources. By optimizing the Aho-Corasick algorithm and integrating Honeypot Intelligence, the system not only detects known and emerging threats but also supports IDS signature creation through collaborative knowledge sharing and honeypot integration. Experimental results show that our approach significantly improves detection rates and reduces false positives, achieving a remarkable 99.71% overall detection rate against UAV intrusions. Additionally, the Lightweight Multi-Tier IDS demonstrates enhanced response times and proactive threat detection capabilities.