Evolution and Comparative Analysis of UAV Software Architectures

The paper focuses on command and control software, discussing the differences between intelligence, surveillance, and reconnaissance (ISR) software architectures, and illustrating how UAV software architecture has evolved from early radio‑controlled prototypes to contemporary interoperable, generic, and video‑compression‑aware systems, citing key references such as Garlan & Shaw (1996) and various UAV case studies.

1. Introduction – Architecture is defined as the structure of components, their relationships, and the guiding principles for design and evolution, encompassing both strategic (component‑based standards, safety) and functional (algorithms, design patterns) aspects.

2. Early UAVs – Early drones lacked software architecture, relying on radio control (RC) technology developed during WWII. The first generation of military UAVs featured modest dimensions, speeds, and endurance, exemplified by the OQ‑1 target drone.

3. Modern UAVs – The first‑generation 21st‑century UAVs (e.g., RQ‑4 Global Hawk, Predator) benefited from satellite communications, advanced computing, real‑time systems, and sensor suites. The second generation introduced heavier payloads, improved positioning, and complex missions such as the J‑UCAS program, with platforms like X‑45, X‑47A/B, and MQ‑8B demonstrating autonomous carrier‑based operations.

4. Architectural Evolution – The DARPA‑funded Software‑Enabled Control (SEC) project (2003) highlighted the need for open, real‑time control platforms (OCP) built on COTS components and CORBA middleware. Subsequent research produced several notable architectures:

Open Control Platform (OCP) – An object‑oriented, plug‑and‑play framework using real‑time CORBA, providing middleware, simulation, tool integration, and APIs.

WITAS Distributed UAV Architecture – A reactive, concentric design implemented on a small UAV (Yamaha RMAX) that leverages CORBA for client/server communication and supports dynamic mode activation.

ARL/PSU Intelligent Controller (IC) – A behavior‑based, hierarchical controller with perception, response, and task‑management layers, enabling fault tolerance, dynamic planning, and multi‑UAV collaboration.

SheLion UAV System – A behavior‑centric architecture featuring a real‑time operating system, multi‑threaded flight control, vision processing, and a ground control station, illustrated with detailed hardware and software block diagrams.

5. Future UAVs – Recent RFI documents indicate the U.S. Navy’s interest in carrier‑based UAVs (UCLASS) that combine ISR and precision strike capabilities, with ongoing efforts to standardize ground‑station architectures and open standards.

6. Conclusion – From the 1940s radio‑controlled targets to today’s autonomous, sensor‑rich platforms, advances in satellite communications, computing power, algorithms, and real‑time control have driven UAV software architecture toward layered, behavior‑based, and open‑control paradigms, setting the stage for next‑generation unmanned combat systems.