Small Modules Make the Big Picture for UAV

July 01, 2024

Blog

Drones carrying out landscape and agricultural surveillance tasks need to capture massive image data sets for 3D modeling and analysis. The smart binary brains of those drones are more and more often built using off-the-shelf credit card sized Computer-on-Modules, seconded by off-the-shelf standard carrier boards.

Such ultra-compact, modular designs are highly scalable while measuring as little as an 8oz pack of butter with less than half the weight. With the release of the new PICMG COM-HPC Mini standard, there is now scope to increase the performance of such systems even further.

Situational awareness is a key driver for the use of drones in landscape and agricultural surveillance and analysis applications. Those drones must capture and process high resolution payloads, with the precise payload requirements differing from application to application and the capturing technologies constantly evolving. For example, coast guards use radio frequency payloads to capture maritime rescue signals. Multispectral sensors, capable of capturing five discrete color bands simultaneously, are perfect for agricultural analysis. And hydro-spectral sensor payloads are useful for identifying harmful algae bloom in lakes. For 3D modeling of landscapes – useful for geoscience, landscape and urban city building projects, or for services such as Google Maps that build a big picture of Earth – massive image data needs to be captured and processed.

Customization is a must for building universal drones

To address all these various scenarios, dedicated payload systems are a common design principle. With such systems, it is possible to mount the appropriate payload in seconds to the different drones needed to handle the various task-related flight requirements. Some tasks may need highly maneuverable multi-rotor drones, others more conventional airplane-like or even amphibious configurations. If the individual components of such payload boxes are also designed with modularity in mind, this enables quick performance configuration to get the right system for the right job. Ultimately, this saves customers from having to buy a new payload system or even an entire new drone for each new improvement in payload technology.

Binary brains for harsh environments

Designing the embedded electronics of such payload boxes is challenging as demands for ruggedness and high performance on the one hand conflict with size, weight, power and cost (aka SWaP-C) limitations on the other. The electronics also must be designed to withstand an extended temperature range from -40°C to +85°C as it can get quite hot under summer sun conditions and without any airflow within the waterproof, fanless enclosed systems. For data processing and storage, as well as for handling the entire aviation of the drones, there is also a need to find a powerful embedded computing platform that can manage all these workloads in real time. It must also connect to central controls, for example via satellite communication. As the size is strictly limited and power consumption must be as low as possible, drone engineers are looking for a solution that can bridge the conflicting demands of high-performance computing in a small form factor with low power demands. It must also be a standard product so that it is as interchangeable as the camera and other payload equipment. Additionally, it needs to match the specific interface, processing and storage requirements as best as possible. Flexible performance is also demanded to perfectly tailor the binary brains to the payloads and enable computing core upgrades as new payload technologies evolve.

Vendor independent standards

So, the embedded computing technology also needs to be selected based on a modular design paradigm. Here, it is worth looking at the new PICMG standard COM-HPC Mini, which positions itself above the massive performance capabilities of existing COM Express Mini modules and thereby addresses the constantly evolving performance needs of drones.

COM-HPC Mini offers many interfaces that COM Express Mini cannot cover, such as USB 3.2 with 20 Gbit/s, USB 4.0 with 40 Gbit/s, PCIe Gen 5/6 with up to 16 lanes, NVMe, and much more. The innovative connector is also essential for this new specification: The COM Express connector revision 3.1 supports PCIe Gen 4.0 with a clock rate of 16 Gbit/s; the new connector, on the other hand, supports transfer rates of more than 32 Gbit/s, enough to support PCIe Gen 5.0 or even Gen 6.0. In addition, COM-HPC Mini provides 400 pins to the carrier board to satisfy the higher interface needs of the new generation of edge computing processors – that’s a staggering 81 percent more than COM Express Mini. Compared to COM Express Basic or Compact, which both offer 440 pins, 90 percent of the capacity of full-fledged Type 6 client modules or headless edge server modules (Type 7) is available. Anyone who doesn’t need the full 100 percent of capacity can consequently switch.

But it is not only performance and connectivity that convince. Even more important is that COM-HPC Mini – same as COM Express Mini – is a vendor independent standard that is designed to bring the performance of high-end commercial processors to the industrial field by utilizing the embedded roadmaps from processor vendors such as Intel, AMD or NXP. These modules enable highly flexible designs and make individual customizations far less time consuming as they deliver an application ready computing core in a standardized credit card sized form factor that is vendor independent. By utilizing Computer-on-Modules, engineers can also immediately upgrade their designs with the latest processor technology by simply changing the module. Custom interfaces are implemented on the modules’ carrier boards. Admittedly, this requires a custom specific carrier board, which produces NRE costs. But designing such PCBs is far less complex than building a fully customized single board computer with all the required logic implementations that the value adding resellers of Computer-on-Modules provide as a standard service.

Off-the-shelf customization

And sometimes there is not even a need for a customized carrier board. For example, an ecosystem partner from congatec was able to utilize an off-the-shelf COM Express Type 10 compliant carrier board for its drones. This is a major benefit as such carriers are readily available, usually shipping within 2-3 days from receipt of order. The ability to use an off-the-shelf carrier board results in a platform that is immediately ready to deploy as it is already proven to work with the preferred module. This is also ideal for lower volume accounts where customization may be difficult to fund. One of the key reasons to choose that particular carrier board was that it has exactly the same footprint (84x55mm) as COM Express Mini modules. This is ideal for space constrained applications in drones. It is also designed for harsh environments with demanding conditions and supports extended temperature ranges of -40°C to +85°C. And it offers an amazing number of interfaces on such a small footprint.

Mini modules for maximum scalability

For the controller as the binary brain of the payload system, congatec’s ecosystem partner recommended to pick COM Express Mini Computer-on-Modules from congatec, one of the originators of this embedded computing standard and draft editor of the latest 3.1 release of the specification. Today, there are various performance classes of those congatec modules deployed in drones to perform computing tasks such as executing the recordings and managing the satellite communication with the central operators. Thanks to the modular approach, the drone vendor can update all its payload processors within seconds by simply changing the module. And just think what inspiring innovations can happen now that the first COM-HPC Mini modules are available: Imagine if the VAR were to launch the same carrier board with identical interfaces. In this case, the drone manufacturer would again be able to upgrade to the new COM-HPC performance class by purchasing everything off-the-shelf. Now, wouldn’t that be impressive and even more reason to rely on modules, even if it means implementing a new standard? Imagine that only the carrier board would need adapting to the new standard. All components could stay the same – at least if the performance requirements remain unchanged. But at the end of the day, the NRE costs that would need to be spent are manageable and by far lower compared to a full custom design. Of course, in this specific case it would not work as COM Express Mini and the existing COTS carrier has a slightly smaller footprint than the new COM-HPC standard, making it impossible to reach the exact size. But based on the Pareto principle, 80% of COM Express Mini carriers available worldwide could be adapted that way.

So, the long term design security will always be guaranteed, even beyond a standard form factor.