Building flexible architectures for configurable UAV systems

Edwin de Jong

July 02, 2008

Edwin de JongJuly 02, 2008

Unmanned autonomous vehicles (UAVs) serve a critical need in a variety of missions, including reconnaissance and search-and-destroy, as well as outside the military in agriculture and forestry.

However, because UAVs are designed for specific mission parameters, it is technically difficult to reconfigure UAV software systems when other missions take a higher priority.

By focusing first and foremost on data interfaces within and between software components along with the integration of those interfaces, UAV system designers can unlock software architectures from a specific technology. The primary objective is to design systems with an unprecedented level of flexibility while improving overall system reliability and sustainability.

Designing and building a UAV is one of the most difficult problems in engineering, and it is particularly challenging from a software systems perspective. As mission parameters change, often it is not possible to adapt software to perform well in changed operating environments.

By optimizing software performance, scalability, availability, reliability, security, interoperability and affordability, system designers can create a UAV that is adaptable to new mission parameters while remaining robust across the product lifecycle.

UAV architecture consists of a set of systems or systems-within-systems with potentially dozens of separate computers and associated subsystems—each processing within its own problem domain - with the need for real-time data communications and interaction with ground control.

Connectivity between systems and components is established using different networking technologies, including spotty wireless links as well as high-speed local-area networks (LANs).

This complexity, combined with the need for constant real-time data exchange between components and between the UAV and ground control, makes adaptation to new missions and roles problematic.

The primary use of a UAV system is to support and enable the mission payload with the necessary means of functioning and to collect and distribute the data from the payload to the end users on the ground. Likely an unmanned system will have complex problems to solve throughout its lifecycle.

What system designers need to aim for very early on is an architecture that can accommodate changes to the system and still retain the basic architecture principles mentioned above.

The key is to leverage existing technologies that abstract design away from a specific, hard-coded implementation. Such technologies have the ability to ease the overall design process while enabling the development of a more robust and flexible architecture. A primary abstraction involves the data interfaces between the various subsystems and components throughout the entire UAV system.

Basic UAV System Components
At the highest level, the UAV design can be segregated into three separate subsystems: the air system, the ground system and the tactical data link that provides real-time communication between the two.

Each of the three subsystems is technically complex, and combining them into a complete system increases the complexity exponentially. The real-time data streams cause rapid and unique interaction events between those systems that must be analyzed and responded to in a timely manner, even though the systems are almost always separated by distance and intermittent connectivity.

The mission-critical nature of UAV systems adds requirements that further complicate the design. Real-time data availability, processing and response are additional requirements, as are high-availability and reliability—all of which typically require complex redundancy management and careful tuning of all code components.

Further, UAVs are almost always designed for specific mission parameters and optimized for those missions. It is unlikely that a ground-imaging or data-collection UAV will be able to readily carry a weapons payload along with its own.

Because of the small size and limited power supply of a UAV, it is currently not easy to swap mission parameters and payloads without difficulty. Too many characteristics tend to be hardwired into the design and implementation to easily configure for multiple mission demands.

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