Enhancing Battlefield Connectivity and Communications
Nett Warrior is the US Army's next generation US integrated soldier system that replaces Land Warrior. It is designed to be an integrated dismounted situational awareness and mission command system for use during combat operations that enables fast and accurate decision-making during tactical operations.
The basic system is comprised of a tactical GPS phone for imaging and texting, various radios for efficient two-way communications, and an optional portable battery pack for power. The End User Device (EUD) — a specially adapted commercial smart phone — graphically displays the location of the squad leader using a digital map image. The EUD uses secure communications channels to transmit and receive information from one Nett Warrior system to another. Armed with advanced navigation, situational awareness and information sharing capabilities, military leaders are able to avoid fratricide and are more effective in the execution of their combat missions.
The electrical interconnect system plays a vital role to the overall performance of the Nett Warrior system. It must be seamlessly integrated into the soldier's vest, pose no serious safety risks to the soldier, and ensure complete functionality throughout the mission.
As the Nett Warrior moved from Low Rate of Initial Production (LRIP) to Full Rate Production (FRP), there were two major issues that the US Army wanted to address: cost and commonality.
Cost and Commonality
The sheer volume of units needed on the battlefield, as well as its associated costs, led the US Government to initiate a Request For Information (RFI) focusing on the development of a universal connector. Potential connector suppliers were given a set of rigid requirements, with an emphasis on three key elements: performance, intermateability, and cost. The down-select process was contingent upon meeting the above criteria. Several rounds of testing were required and completed over a two-year period to ensure the highest degree of reliability.
The US army required the connectors to be lightweight; rugged; operate in harsh environments; provide a safe, reliable, consistent break-away force; and transmit data compatible with USB 2.1 busing architecture.
The connectors were tested in accordance with Mil Std 810 G method 516.6 for shock and Mil Standard 810G method 514.7 for vibration. To ensure reliability, the connectors were also subjected to a 2000 mate-de-mate requirement with no loss of signal integrity. A separate test was performed that ensured full backward compatibility with the incumbent design, including a break-away force test that ensured that the connectors de-mated at the specified value of 13 lbs +/- 3lbs.
The electrical requirements included meeting an Insulation Resistance value of 100 MΩ at 500 Volts DC, 5 Amps power rating per contact, and meeting the USB 2.1 signal integrity profile.
The US Army was ultimately successful in authorizing a second source of supply, which minimized their risk and reduced their overall costs.
Next Generation Soldier Connectivity
In the modern age of increased weaponry and adaptability, soldier technology must constantly evolve to meet the challenges that the warfighter will face in the next decade and beyond. Electrical interconnect will be an increasingly important part of the overall solution, as the soldier and the battlefield become more connected. To anticipate future electrical system enhancements, it is first important to consider the unique challenges future soldier-systems will face.
One challenge that future soldier-systems will certainly deal with is the harsh environments that soldiers inevitably face. Temperature extremes, rain, mud, dust, sand and even temporary water immersion are and will remain typical battlefield conditions in which soldier-systems must operate. When exposed to these situations, the connectors must not fail.
If a connector is disconnected for any reason, the soldier may need to clean the connector for optimum performance. Traditional pin and socket connectors used in today's Nett Warrior system present a significant challenge related to field cleaning. Thus, a possible area of improvement in next generation soldier system connectors would be a design that uses a “dead face” style of contact system, where the pin is typically spring loaded and the traditional socket contact is replaced by a solid disk of metal. This type of contact interface is inherently more cleanable than other designs.
Water immersion creates unique challenges for connector manufacturers. Essentially, the connector must protect the integrity of the signals from the outside elements. Today, Ingress Protection (IP) standard, IP-67, is the current requirement. However, there is every reason to believe that IP-67 will be replaced by IP-68, meaning it must survive all current conditions with the addition of being immersed in 1.5 meters of water continuously for up to 30 minutes or longer, which may pose some design challenges. Generally speaking, protection in a mated condition is much less of a challenge than when the connectors are unmated. This is another argument for a “dead face” style of connector that can be designed to be IP 67 or 68 compatible, even in an unmated condition.
As more electronics are added to the soldier's load, connector manufacturers must continue to find innovative ways to reduce connector weight. Depending on the mission being carried out, a soldier must shoulder loads of up to 100 lbs, which can drastically limit their effectiveness on the battlefield. Developing connectors and assemblies that are smaller, more conformal fitting, and lighter weight can help to improve soldier effectiveness.
As future soldier-systems are introduced, it is expected that the use of composite materials, like LCP, PEEK or ULTEM for connector shells will be expanded. These materials offer higher strength to weight ratios over traditional aluminum-based connectors, resulting in weight savings of 20 to 30% over similar aluminum shell connectors used today.
The use of composite materials does require plating for adequate Electro-Magnetic Interference (EMI) performance. However, unlike aluminum shell connectors used today, composite materials lack a galvanic relationship between the base material and the protective plating. In today's connectors, the aluminum base metal and the nickel-based plating material are at opposite ends of the galvanic scale, requiring very precise and careful surface treatment and plating methods to prevent galvanic corrosion. Since composite connector shell base material is non-metallic, this design concern is virtually eliminated. Salt spray endurance tests of over 2,000 hours have been successfully demonstrated in composite shell connectors.
Finally, composite materials can be molded into almost any imaginable shape in a very cost-effective manner using modern injection molding techniques. This creates the ability to engineer a connector shell that is low profile and easily integrated into solder vests and protective equipment.
The current Nett Warrior system is built upon a USB 2.0 busing architecture, which is limited to a data transfer rate of 480 Mb/second. As the battlefield becomes more connected, data and video transfer will see a rise within the next 10 years which, most likely, will require USB 3.0 signaling speeds (5 Gb/second) and perhaps beyond. The future soldier-system will invariably require higher pin count density for increased capability while maintaining a similar or smaller footprint. Small form factor connectors like micro D- or nano D-type connectors could form the basis for a new soldier connector by leveraging the higher contact density, smaller size, and lighter weight format. Adapting connectors of this pin density to achieve high speeds would be key to providing a smaller, lighter connector purpose-built for high-speed signaling.
High-speed board level connectors like the TE Connectivity MULTIGIG RT2-R, designed to meet the VITA 46 standard, that utilize small printed circuit board wafers, are modular in design and can handle signal, power and high speed signaling with speeds of up to 12 gigabits of data per second. They interconnect via an industry standard interface and are electrically engaged via a wiping action on the surface of each wafer. This type of connector design could also have some important benefits in a new, low profile soldier connector. The high-speed signaling capability, along with the small size and weight, could form the basis for a future soldier connector that would be a significant deviation from a traditional pin and socket connector.
Connector manufacturers today have the engineering resources to develop and construct complete systems so that if initiated at the very onset of a program, a cost effective, optimized interconnect system could be developed. If the connector/cabling solutions are designed as a system, board level style connectors similar to VITA 46 connectors that achieve extremely high data rates could be utilized to achieve data rates previously not possible in traditional systems.
Nett Warrior has revolutionized the battlefield intelligence available to today's fighting soldier. Through it, soldiers are more informed and better connected than ever before. However, future enhancements in technology and capability will drive the next generation of soldier-systems to new levels of capability and efficiency.
Future technologies will require faster data transfer, more power, smaller size, lighter weight, better conformability, improved maintainability, modularity and unfailing reliability. The connector industry is prepared to engineer solutions that meet these needs and is working with the defense industry to develop appropriate solutions.
This article was written by Steve McIntire, Manager, Product Management, TE Connectivity (Berwyn, PA). For more information, Click Here .