RF+Digital Building Blocks Open New Possibilities for Modern EW Systems

The continued growth of mobile networks and advancing digital technologies are significantly impacting military and aerospace systems and operations. Enormous strain is now placed on the available RF spectrum for the command, control and communication requirements of the Department of Defense (DoD). It is also making it easier for adversaries to use hidden signals for nefarious missions.

For these reasons, a new approach needs to be taken with regard to the electromagnetic spectrum and as importantly, how the military can most effectively use it. In fact, DoD leadership has implemented an electromagnetic spectrum superiority strategy that is focused on three "Cs":

• Contested environment: Adversaries have become better at jamming the spectrum. Effective countermeasures must be developed. 
• Congested spectrum: The spectrum is being used by many more entities, domestic and abroad, including in actual warfare as well as military training. 
• Constrained spectrum: Domestic and international regulations have decreased the amount of spectrum available for military access. More efficient use is necessary, as a result. 

One aspect of the plan to address the three critical elements is developing advanced electronic warfare (EW) systems with high-fidelity wideband RF performance. It is necessary to ensure no signals are missed to achieve optimum spectral awareness, for offensive and countermeasure initiatives. 

There are also emerging EW system design factors that require a disruptive approach and advanced technologies. Among the most critical are:

• More compact EW systems: From attritables and precision munitions to unmanned vehicles and more, modern EW is becoming smaller and lighter while also meeting more complex RF threats.
• Rapid deployment: There is a DoD initiative to have shorter and more cost-efficient project timelines, from concept to deployment. This is necessary in today’s battlefield, which is advancing faster than previous generations.  
• Open architecture: To that end, the DoD is placing greater focus on open standards, especially Sensor Open Systems Architecture (SOSA). Open environments are expected to control costs, create more design options, and make adaptability and project updates easier and more efficient. 

A Company with a Rich History Pays Dividends

While such market trends will introduce new players into EW, to effectively address the performance, size, and price demands, an established company experienced in EW is necessary. Decades of industry knowledge and leadership create a strong foundation upon which the building blocks of the future of EW systems can sit.  

Spectrum Control has more than 70 years of RF and electromagnetic spectrum experience. A new executive leadership team at Spectrum Control is blending that spectrum leadership with a clear vision of addressing the new EW dynamics. 

New Design and Manufacturing Technologies

One critical element to meet today’s EW system requirements is to change how engineering is done. RF and digital engineering teams traditionally work in silos. Digital engineers are concerned with specifications, such as clock rates, speed of internal devices, storage, memory, and most importantly, software. Conversely, RF designers focus on other functions, including impedance traces, VSWR matching, and noise created by system components based on the board layout. RF engineers also are concerned with voltage, high slew rates, noise, and other factors associated with digital circuitry that can degrade RF performance. 

Compounding the differing mindsets is that each design team typically wears virtual blinders. Both engineering groups are so focused on their responsibilities and concerns that they have always had a blind spot toward each other. Their eyes – and minds – only open when the RF and digital elements have to be integrated into the component or module. 

The result is a design nightmare. Often, engineering teams are forced to develop a “back door” late in the process to overcome calibration and overall compatibility issues. This extra step leads to multi-month delays in development schedules and adds days to every single device that is tested. Subsequently, design costs increase and timelines slip.

A collaborative approach, such as the one implemented at Spectrum Control, eliminates all delays, added costs, and headaches associated with the traditional approach. Greater systems engineering functionality is created. 

The end result of this disruptive method is innovative design and manufacturing technologies for integrated solutions that address emerging EW environments. A key advantage is that the solutions are developed based entirely on surface-mount technology (SMT), a significant departure from how the industry has historically designed modules of this type. Taking this approach adds speed and reliability to the manufacturing process and provides critical advantages in building the next-generation supply chains customers need post-pandemic. 

Modular, Flexible RF+Digital Building Blocks

With digital engineering teams working side-by-side with RF engineers from the start of the project, digital controls and RF functions can be developed synergistically from the onset of the design process. The resulting digital gateway into the RF domain offers multiple benefits such as a streamlined process, an efficient design path for SOSA-aligned products, and greater flexibility, testability, and extendibility.  

A common software interface similar to a digital card is used to create the digital gateway into RF. A clear communications path is established by the digital gateway for a hierarchical, modular, and open approach to controlling RF components, modules, and subsystems. The result is compatible functionality, including circuitry and voltage. With such a gateway, RF engineers have a clear vision of the digital aspects, such as calibration controls and temperature compensation.

Scalable Solutions for EW Systems

Next, a scalable architecture is created, so digital and RF designs can be right-sized for the specific project. The digital gateway facilitates a new level of software control that delivers a greater degree of RF flexibility, interoperability, and mission agility. RF controls and software can be integrated seamlessly and efficiently. Many issues and problems associated with the more traditional approach are eliminated. 

Digital gateway building blocks can be used to realize more agile EW subsystems, systems, and systems-of-systems and comply with SOSA standards. Spectrum Control is using these open standard RF+ system blocks to develop the SCi Blocks (“sky blocks”) family of next-generation RF+Digital solutions that address the size, weight, power and cost (SWaP-C) and open architecture requirements of emerging military and aerospace system designs. Key innovations using Field Programmable Gate Array (FPGA) technology and 2.5D manufacturing are enabling a no-compromise improvement in digital enablement without affecting size, weight, power, or performance. 

High-density, high fidelity, wideband RF solutions can be developed with the SCI Blocks architecture at three levels – System-in-Package chips (SiPs), RF-on-mezzanine, and SOSA-aligned 3U VPX modules that slide into a standard chassis/backplane. The lower levels of the architecture are designed to be used standalone and to readily integrate into the higher levels.

The SCi Blocks architecture reduces product development and bring-up activities by 50%. It is expected to translate into significant savings for customers in integration, qualification, and low-rate initial production. Table 1 outlines the performance specifications for the SCi Block wideband up/downconverter.

Table 1: SCi Block wideband up/downconverter specifications.

The open architecture characteristics of the RF-on-mezzanine product (figure 2) align with SOSA standards. The modularity embedded in the SCi Blocks architecture allows for various combinations of upconverters or downconverters in the 3U OpenVPX form factor to support various mission configurations. It provides repeatable, high-performance without the need for manual tuning.

Figure 2: A SOSA-aligned 3U VPX module with flexible RF-on mezzanine architecture meets the SWaP-C requirements of modern military and aerospace systems

EW Transceiver Benefits

The benefits of SCi Blocks are seen in virtually any design, such as an EW transceiver. A transceiver can be built utilizing 4 upconverters and 4 downconverters, each covering 2 GHz of the electromagnetic spectrum for a total of 8 GHz of bidirectional frequency coverage. Two SCi Blocks modules can produce 16 GHz of both receive and transmit capabilities to an EW system such as a wideband Digital Radio Frequency Memory (DRFM).

A scalable physical architecture for the 1 GbE, 10 GbE, and 40 GbE interfaces is implemented. It enables retrofitting into currently deployed systems without changing existing system software. The system on chip (SoC) may also be used to implement Vita 49.2 messaging and data path protocols for future products. 

VPX Modules for EW Systems

VPX modules are also digitally-enabled and more importantly, SOSA-aligned. This is made possible through the incorporation of the SCi Block Manager, a higher-level control function built into every module. The Manager can be programmed to execute a variety of built-in test functions, as well as control the RF performance of the module to accommodate changes in the operating environment and mission requirements. By allowing system integrators a common command and control infrastructure for various RF circuitry, the SCi Blocks Manager lends itself to much faster system integration.

Consolidating various RF front-end features in SCi 3U Open VPX modules yields another SWaP advantage leading to a unique small form factor EW system (figure 3).

Figure 3: SCi Blocks small form factor EW system

The SCi Blocks module utilizes 4 downconverters for an ES receiver to provide situational awareness. Two upconverters and downconverters are paired to produce the RF front-end for a wideband DRFM. The common command and control architecture for the SCi Blocks module along with the SOSA-aligned interfaces allows for quick and easy integration with the various Digital Signal Processing (DSP) elements and single board computers (SBCs). The combination can add new EW capabilities to small platforms such as Unmanned Aerial Systems (UAS) previously unavailable due to SWaP-C constraints.

Plug-and-play Building Blocks for EW

These examples show how the SCi Blocks architecture serves as a “plug-and-play” solution for EW platforms. Three main benefits are realized with the new design approach: 

Rapid system integration: A standard digital interface allows plug-and-play solutions to be efficiently designed into EW/ISR systems, saving time and money. The creation of the digital gateway results in RF solutions that are functionality similar, so every system is more efficiently developed. The DoD initiative for shorter timelines and development cycles is met. 

Faster modifications: Military and aerospace systems can be modified much faster using this approach because all that is necessary is software enhancements. Traditional RF systems also had a hardware upgrade requirement, which resulted in longer turnaround times. What had traditionally taken months, or a year, can now be done in days or weeks. 

Adaptability: The ability to efficiently create modular solutions that integrate various levels of RF performance depending upon the project requirements allows for greater mission flexibility. It also expands future design approaches by reducing traditional cost and time constraints.  

Conclusion

Some estimates state that 75% of the cost of a defense project is associated with integrating components and modules. Development of SCi Blocks plug-and-play digitally-enabled RF building blocks provides the solutions to meet emerging designs in a time- and cost-efficient manner. SCi Blocks also expand EW capabilities into applications that were previously limited by SWaP-C concerns.