The ruggedness of common tablets and smartphones, such as those manufactured by Samsung and Apple, has improved in recent years. The addition of rubber overmold accessories enhances drop survival and the use of connectors and sealing techniques enhance water resistance. However, these devices, even within rugged outer casings, cannot meet the more demanding set of standards required by tablets and other portable devices for the military.
Military devices are used for a wide variety of applications. These include:
- UAV (unmanned aerial vehicle), UGV (unmanned ground vehicle), and UUV (unmanned underwater vehicle)) deployment and control
- Real time personnel, vehicle, and equipment tracking and deployment
- GIS (geographic information system) mapping
- Mission planning command and control
- Real time situational awareness and analysis, including friendly and enemy force tracking
- Security and military police operations
- Field logistics and dispatch
Being used in the field, these devices must withstand virtually any environmental condition while also fulfilling operational reliability through any mission or maneuver on land, sea, and air. Many ruggedness requirements are defined by MIL-STD-810G. The electronics, including the touchscreen and display, must operate across very wide temperature ranges outdoors. Devices must withstand immersion in water, driving rain, blowing sand and dust, drops, pressure changes due to altitude, and the corrosive effects of salt water. Their displays must be easily readable in direct sunlight, but also be sufficiently dimmable to accommodate night vision standards in the dark.
Because of their unique use cases, military tablets and portable devices are specially designed to meet the challenge. Considerations include:
- Electronics components rated for extended temperatures, such as the common -40˚C to 85˚C industrial temperature range. Consumer grade devices often use components rated for 0˚C to 50˚C and may fail when used outside the range.
- Displays ruggedized to absorb direct impacts without breakage. Enhanced packaging and the use of chemically strengthened glass, especially as cover glass or the base layer of a touchscreen helps. Optical bonding of the touchscreen and/or cover glass to the front of the display adds further strength, and also eliminates glare that can wash out the display.
- Use of resistive touchscreens, as opposed to the capacitive touchscreens used in consumer smartphones and tablets. Resistive touchscreens can be used with thick gloves, such as MOPP gloves, and in wet environments. Capacitive technology is for these use cases is improving.
- Incorporation of specialized circuitry required for military missions, such as military band radios, SAASM GPS, and specific security modules. These must be considered not only in terms of electronic and software integration, but also in the handling procedures of devices that may be classified.
- Security for military tablets and portable devices is crucial for protecting data, mission plans, and therefore lives. This ranges from data encryption and user authentication to the detection of physical device tamper, where triggers set off by opening the enclosure may erase encryption keys and zeroize memory. Some operating systems, such as SUSE or Red Hat Linux, include cybersecurity and other features that enhance device security. Additionally, a custom device can be locked down, such that software updates aren’t pushed to it uncontrolled, as is done with consumer tablets.
- Size, weight, and power (SWaP) must be minimized. This requires careful tradeoffs between battery size, time between charges (which must fit mission parameters), materials used for the enclosure, and how the device fits within the pouches and packs that are used to storage and transport.
- Thermal management within the device is critical, to ensure that components do not overheat and potentially fail (or fail sooner than their rated lives). Military devices are usually sealed to prevent water and dust ingress, which means there is no mechanism to ventilate heat out of the device. Careful diligence is required to prevent heat generation to the extent possible, but once produced it must be intelligently spread through the device. Parts of the device exposed to the user must not be uncomfortable to touch.
- The military tablet or portable devices must be easily usable, to facilitate the mission, not impede it. MIL-STD-1472 defines human factors design criteria for military devices.
- Production and support longevity are critical for the resulting military device. Relatively long design and qualification cycles combined with mission integration and training dictate that production and repair over a period of many years. Therefore, components utilized within the tablet or device must similarly be available, and these components must be identified at the start of the design.
As implied by the above list of considerations, the design of a military tablet or other portable military device is a complex undertaking. There are wide-ranging system, electronic, mechanical, software, supply chain, and even procedural optimizations that must be made to produce a rugged, secure product meeting a diverse set of needs.
InHand Electronics has been delivering military devices that meet the most demanding design and operational requirements for many years. InHand specializes in the design and delivery of small, battery operated embedded computers, rugged tablets, portable and handheld devices, and more for military, industrial, and medical industries. Contact InHand for an evaluation of your application.