Unmanned Systems Technology 042 | Mayflower Autonomous Ship | Embedded Computing | ElevonX Sierra VTOL | UUVs insight | Flygas Engineering GAS418S | Ocean Business 2021 report | Electric motors | Priva Kompano

43 there is a standardised format for a processor board with a defined size and pin-out sitting on a carrier board. This carrier board then provides the customised sensor or I/O capabilities. COM Express The COM Express specification defines a family of Small Form Factor (SFF) and Computer On Module (COM) single- board computers appropriate for a wide range of commercial and military/ aerospace applications using x86 processors. It is designed for the latest serial signalling protocols, including PCI Express Gen 3, 10 Gigabit Ethernet (10GbE), SATA, USB 3.0 and high- resolution video interfaces. COM Express modules can be used as a standalone single-board computer or as a processor mezzanine that can be plugged onto a base board (‘carrier’ board) that contains the I/O interfaces specific to the application. The carrier board is less complex to design and build than a single-board computer that includes the processor, typically with one or two PCB layers rather than four or more, and so allows a shorter development time. Carrier boards can themselves adhere to other standards such as Mini ITX. There are also moves to develop carrier boards to the OpenVPX standard (see sidebar: OpenVPX) that would accommodate a COM Express module for the emerging SOSA open sensor applications (see sidebar: The Sensor Open Systems Architecture) The ability to plug a COM Express module onto a carrier board reduces the time and cost to develop a product, as the user does not need to understand the often complex details associated with high-speed signalling or the latest chipsets. A customer’s product lifetime is increased, as newer COM Express modules can simply be plugged into the carrier board to improve performance or lower their cost. This is a key capability, and allows a designer to upgrade the processor to higher performance or, more important, to a later processor with additional security features. This ease of upgrade overcomes the penalty of having the carrier as an additional board with extra connectors, which can reduce reliability in applications with a lot of vibration. The publication of the rugged COM Express standard in 2018 opened up many opportunities in unmanned systems, with processors and LPDDR4 memory soldered directly to the module rather than in a socket. That helps to improve the vibration resistance and the thermal management of the module. Because SFF applications often need to strike a careful balance between cost and performance, a variety of COM Express form factors and board sizes are defined in the standard. This can make specifying the COM Express modules, and the associated processors, complex. There are four form factors and eight different types of connector for each board. Revision 3.0 of COM Express tried to sort this out, making Types 1 to 5 legacy and leaving Types 6, 7 and 10 as the main formats. Type 6 tends to be most popular for unmanned systems, with up to 24 lanes of PCI Express and processors up to the Intel Core i7 U-class processor. Type 7 provides for the addition of up to four 10GbE interfaces on the board and increases the number of PCI Express lanes to 32 for graphics GPUs and AI applications as well as higher performance servers. Type 10 supports higher performance Intel processors up to the Apollo Lake and now the Elk Hart Lake class. Embedded computing | Focus Unmanned Systems Technology | February/March 2022 The PE4-UV is a compact engine management system developed specifically for unmanned vehicles (Courtesy of Performance Electronics) The different form factors for COM Express processor modules (Courtesy of Kontron)