A General Atomics MQ-9 Reaper, a hunter-killer surveillance UAV
Unmanned aerial vehicles (UAVs), colloquially known as drones, are aircraft designed to be piloted without a human on board. Drones are finding realistic uses outside the military, including applications in surveillance, agriculture, search and rescue, scientific studies, shipping, and many other areas.
As tactical demands increase, so have the processing, memory, and ruggedness requirements in military-grade single board computer systems. These systems are critical for running the embedded software that controls a UAV’s flight path, surveillance systems, weapons systems, and communication with a base station. There are a number of products available on the market, but more specialized classes of UAVs may need very particular form factor, communication, and processing requirements.
Basic Requirements for Military UAVs
Most commonly-available UAVs are civilian-based, yet military UAVs are by far the most advanced. Unlike Civilian UAVs, military systems carry much more stringent design requirements and must be designed to MIL-STD standards. Military UAVs are designed to be deployed in the harshest conditions while being exposed to electronic jamming from enemy troops, interference, heat, noise, and other dangers. The following list contains some basic design and development requirements for military-grade single board computers for use in UAVs:
Communication: Communication is one of the core requirements for developing a UAVs. Because of the adverse nature of military UAVs, it is expected that the device should be able to support more than one communication layer, such as satellite, cellular, and other protocols.
Control and non-payload communication (CNPC), also known as command and control (C2) communication, is of critical importance for controlling a UAV during flight. The non-payload communication link is dedicated to secure communication between a remote pilot at a ground control station and the UAV to ensure safe and effective operation during flight. A line of sight (LOS) air-ground (AG) link or a beyond line-of-sight (BLOS) link using another platform (e.g., a satellite or high altitude platform (HAP)) can be used for communication between the two entities. Data rates for such links are expected to be modest (e.g., 300 kbps for compressed video streaming, which would not be used continuously).
Real-time critical systems: UAVs must be able to quickly send sensor data and video data over long distances. Lag and latency are undesirable and could be a deciding performance factor. Newer UAVs also require real-time telemetry data with GPS navigation.
Reliability and durability: These systems should be rugged against mechanical shock, ESD, and extreme environmental conditions. Ideally, UAVs should be functional in nearly any weather conditions with long uptime. This requires power management at IC and board level for extending battery life during flight.
Military Grade PCBs
At the core of every embedded product is the PCB, which will significantly influence the durability and reliability of the product. For military-grade single board computers in applications like UAVs, PCBs must adhere to a set of the military-based standards, most of which are derived from the IPC-A-610E Class 3 standard. Because of the performance requirements of electronic products needed in this industry, these standards provide specific performance requirements that are designed to ensure reliability in harsh environments.
High operating temperature requirements, vendor complaints, ESD suppression, power consumption, and thermal management, are some of the factors that need to be considered when working on military-grade PCBs. The MIL-PRF-31032 set of standards provides the strictest rules that should apply to PCBs for use in military equipment, including UAVs.
Designing a PCB is one aspect; manufacturing is another. PCBs for use in military applications like UAVs should be manufactured in conformance to MIL-PRF-50884, MIL-PRF-31032, and MIL-PRF-55110 standards; this means the modular single board computer should follow suit with those standards. Regarding manufacturing, engineers need military quality standards and manufacturers that comply with procurement regulations. The manufacturer you choose should be certified to manufacture electronics for aerospace and military systems under AS9100.
The processing capabilities will significantly influence the performance of the overall system. There are several options to consider for a modular military-grade single board computer targeted towards UAVs. ARM processors are an excellent choice for any mobile system; in particular, the TI Sitara AM4378 is an excellent choice for a military-grade single board computer for a UAV/MAV. The Poblano 43C board from Gumstix includes this processor. An SoC-based mobile class processor is an excellent choice from a footprint perspective as this consolidates CPU, I/O, and memory controllers within a single IC package. These packages tend to come with integrated power management capabilities, making them power efficient and extending uptime.
Adding Modules to a Military-grade Single Board Computer
Some components you should include in a board for UAVs are cameras and imaging systems, communications modules, and a navigation module. Working with a modular design platform allows you to mix and match the capabilities you need for your next UAV. A COM with the TI Sitara AM4378 mentioned above is a great platform for building your board.
Working with modular design tools makes it easy to add navigation capabilities to a UAV. The ZED-F9P GNSS module from Gumstix is an excellent choice for a GNSS module with RTK support. This particular module interfaces with standard COMs using a USB micro-B connector, and it includes an SMA connector for an external antenna. The module also provides centimeter-level accuracy, and RTK data is provided using two ZED-F9P boards. You can easily bring this module into your new board using Geppetto, as shown in the image below.
Adding the ZED-F9P GNSS module to a new board in Geppetto
There is plenty of functionality you can add to your board beyond GNSS navigation capabilities. Some possible modules include weather sensors, cameras, power regulation components, and a variety of connectors for interfacing with off-board equipment. Bringing all these components together in one place takes the right design tools that include the modules you need in a single platform.
Military Grade Single Board Computer Design in Geppetto
Geppetto by Gumstix is an online platform that allows designers, engineers, makers, and others to build an embedded platform without worrying about the finer points of PCB design. Geppetto is built on the modular philosophy, allowing engineers to easily add new functionality to existing boards. Geppetto provides all the tools needed to take a board from idea to production in a single environment.
Customizing a COM with Geppetto’s design-to-order service
Geppetto also gives you the option to clone an existing design and use it directly as the base of your own build. Gumstix gives you the option to customize your AeroCore 2 board using their modular design tools. You can tailor the footprint and functionality to your particular application. You’ll also have the freedom to add an array of sensors or other features directly to your custom board.
The modular design tools in Geppetto can help you quickly create cutting-edge military-grade single board computers for any application. You’ll have access to industry-standard COMs and modules, allowing you to easily create production-ready hardware.
About the AuthorMore Content by Zachariah Peterson