Date of Award

Spring 2015

Access Restriction

Campus Access only Research Projects

Degree Name

Master of Science


Systems Engineering

School or College

Seaver College of Science and Engineering

First Advisor

Karen Miller


Unmanned Aerial Vehicles (UAVs) are common place in the 21st century, whether they are small to medium sized remotely piloted vehicles (aka drones) or large advanced Unmanned Aerial Systems with a preprogrammed flight path. There is anticipation that these Unmanned Systems will, in the future assume the roles of their traditional manned aircraft counterparts. There is also the perception that these Unmanned Systems should be developed partly because they would be less expensive when compared to their manned aircraft. This integrative paper asserts that this perception is not reality with regards to developing a newly designed UAV to replace its manned counterpart, for the same mission. Through the examination of systems engineering principles between the unmanned RQ-4 Global Hawk and the manned U-2 Dragon Lady one will understand why this perception is not correct. Both aircraft perform the same mission of providing High Altitude Intelligence, Surveillance, and Reconnaissance (ISR). Through evaluation of requirements analysis both aircraft flowed down the requirements to all the various subsystems in a similar manner, creating similar subsystems for Imagery Intelligence (!MINT) and Signals Intelligence (SIGINT). However, the additional requirement for long endurance required that the Global Hawk systems engineers had additional requirements to flow down to the software, communications, data processing, and ground support subsystems in order to control an unmanned aircraft for greater than 24 hours. This one additional requirement had various derived requirements that needed to be verified, and validated during analysis, manufacturing, subsystem build and test, and final system integration. By using both System Integration Laboratories (SIL) and Flight Tests both systems requirements were verified and validated by the systems engineers. The Global Hawk since it was unmanned was required to perform more verification of subsystems and software as it was the first UAV to achieve flight airworthiness. The future of ISR missions requires that the aircraft become more adaptable to future technologies and situations. The U-2 has a modular configuration to change out to and from different subsystems depending on the mission. However, these subsystems were designed 20 to 30 years ago, and were not designed for lower level modularity or interoperability. The Global Hawk systems engineering team understood the future needs and the high level demand and data to be gathered and processed. The SE's developed modularity and interoperability requirements and flowed them down to the various subsystems. The Global Hawk system is more useful in highly contested areas of interest as there is no pilot; however resilient communications of the data and data link must be robust with anti-jamming capabilities to ensure the data is secure from cyber-attack. However,the U-2 is more survivable since it has a defense system, and can provide greater situational awareness. Taking all the general ISR requirements into consideration a trade study using a matrix was performed indicating that the Global Hawk is the most optimal solution to meeting both the current and future requirements for ISR missions. Even though the overall acquisition cost of the Global Hawk is equivalent to the U-2, systems engineering for Global Hawk had the responsibility to flow down requirements to all subsystems with consideration of the entire systems lifecycle. This is exemplified in that the Global Hawk is cost effective to fly in terms of cost per flight hour. Therefore, the Global Hawk can fulfill all the requirements of the given stakeholders with the lowest operational cost.

IgnacioSerrano_Systems_Presentation_2015.pdf (12666 kB)
Oral Presentation