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How to Overcome Radar Simulation System Challenges

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by Marcelo Ramos, Vice President of Engineering for RF Sources/Receivers, dB Control

When designing electronic warfare (EW) equipment—in this case, radar simulation systems—or any other defense-focused project, the aim of preserving lives makes your principal concern system effectiveness. To achieve this end, you require test equipment you can trust to be both accurate and reliable, even in adverse conditions. This article examines the challenges faced by EW system engineers in testing the effectiveness of their designs—in terms of technical demands, in-house capability, and, of course, cost.

Radar Simulation Challenges

Radar simulation systems, comprising RF sources and/or receivers, depending on the application, must perform to an exacting minimum standard if they are to definitively prove the field-worthiness of EW systems. Transmitter frequency set-on time must be as fast as possible and frequency needs to be as stable as possible over the entire operational and temperature range, as well as across a wide bandwidth. A common demand is a set-on time of 1 microsecond (μs) and the frequency held within 1 millisecond (ms).

Similarly, receivers must measure frequency accurately, as fast as possible, while maintaining a stable frequency over the entire operational and temperature range, as well as across a wide bandwidth. Normally, one must (at least) measure within 100 nanoseconds (ns) with an accuracy of one megahertz (MHz). Of these two test elements, greater challenges are encountered with the transmitter due to testers’ desire for an ever-faster signaling time (even faster than 1 μs).

Test systems can be built in-house by companies in need, but often know-how or resources are lacking.

Organizations seeking to achieve these efficiencies in-house often err in budget, timeframe, resources, expertise, or a combination of those factors. Some companies overestimate their in-house capabilities, while others underestimate the complexity of designing and building the product or miscalculate the cost of doing it in-house.

The dB-9003 from dB Control is an Integrated Stabilized RF Source (ISRFS) operating in the I- and Ka-band frequency range

Often, the extent of these companies’ problems only becomes apparent late in the engineering process. Designers discover that creating a solution with the proper capabilities—meeting specific size, weight, and power (SWaP) requirements, within their budget and timeline—is not possible.

For example, SWaP needs generally are rigid in these equipment specifications. Smaller platforms (e.g., a drone) are likely to have tight size specifications. Prime power, though, often represents the most challenging specification to fulfill. Customers always want a more efficient system, drawing less power. Generally, customers have a baseline number in mind.

Several options exist for creating and receiving a signal, and testers must determine the optimal equipment relevant to their systems. Both frequency-locked oscillators (FLOs) and voltage-controlled oscillators (VCOs) can cover a range of frequencies. FLOs can be designed to accommodate various modulations, such as AM, FM, and PM—representing one of their key desirable attributes.

As an alternative, synthesizers can achieve significantly faster signaling times than oscillator-based test systems, but synthesizer technology is limited by several disadvantages. Primarily, synthesizers cannot be easily modulated in FM, and bandwidth suffers. Further, synthesizers commonly suffer spurious signals (spurs) and, most critically, synthesizers cost almost 10 times more than oscillator-based test systems.

Finally, developers must consider system control elements. Antenna control units (ACUs) are able to play prerecorded antenna patterns and can compensate for platform movements. For example, they can compensate for tilt and roll when mounted on an aircraft. Instantaneous frequency measurement (IFM) units measure frequency and power level, as well as detect pulse on pulse signals.

Digital control units (DCUs), meanwhile, are capable of controlling a single FLO and other RF equipment. Integrated DCUs (IDCUs) combine the control and interface power of a DCU with the RF capabilities of a FLO and the capabilities of an ACU for a complete integrated system controller in a single unit. While it absolutely is possible to create a radar simulation system in-house, it’s also pragmatic to acknowledge that your company likely can get a superior system, cheaper, somewhere else.

An Inside Look at dB Control

Defense electronics manufacturer dB Control always bids in compliance to a specification that the customer has provided. The company’s custom equipment meets hard-to-fill user expectations. In fact, this equipment is difficult (or impossible) to acquire off the shelf or to design in-house. dB Control’s specialty and expertise lies in meeting stringent requirements at a price point, size, weight, and prime power that meet all stipulated customer requirements.

Additionally, dB Control guarantees accuracy that can be otherwise difficult to obtain, especially over the temperature range many testers demand. For example, one dB Control client requires parts that work from -40°C (-40°F) to +71°C (159.8°F).

That temperature operating range is solved through various methods, including design, choice of materials, and heating components inside the unit that maintain a constant internal temperature. dB Control also digitally calibrates every system element to compensate for whatever may not have been addressed (in terms of temperature) via physical means.

Finally, consider that many of dB Control’s products have been sold for decades, establishing a reputation for system reliability and stability over that span. Since the base designs of such systems have changed little over that time, designers have focused on improvements that allow the systems to perform optimally over a long timeline.

How Does the Customization Process Work?

Consider the previously mentioned client who needed equipment that remained effective across a range of temperature extremes. That client comes to dB Control with precise specs; they know exactly what they want.

A second client’s experience, though, is more typical: dB Control has visited the client, observed their resources, and helped the company to, in effect, generate appropriate specs for the application.  

Regardless of the starting point, the test system inevitably is tweaked by dB Control for optimal operation—primarily because the digital interface needs to be personalized for each customer; it’s very specific.

While dB Control is not unique among vendors in providing these testing systems (though not many companies build these types of products), combining flexibility with expertise sets dB Control apart. For example, competitors generally want precise specs and, once something is agreed upon, everything is set in stone. dB Control can, and does, modify orders even after the design process has begun. 

This flexibility is aided by diverse in-house expertise: not only does dB Control have expertise in frequency products, but in amplifiers, as well—making it one of the few companies with expertise and products in both realms.

Timelines are handled on a case-by-case basis with the customer. They can be affected by incomplete or ambiguous specifications from the customer. Obviously, this process can be drawn out by a lot of back-and-forth, or a customer not knowing exactly what they want. Ultimately, any challenge is welcomed.

Take a Consultative Approach to Your Test Systems

Any supplier can sell you a radar simulation system and claim it will work as promised (laying unforeseen issues at the feet of the user after a sale is complete). Thus, considering what’s at stake, and the budgets surrounding EW equipment, you may prefer to seek a consultative approach to your test systems, rather than a transactional one. The latter path could be devoid of guiding expertise in its early stages (e.g., providing aid in setting your specs), or lacking in post-sale support (e.g., adjusting the system on the fly, as needed).

About dB Control

Established in 1990, dB Control Corp. supplies mission-critical, often sole-source, products worldwide to military organizations, as well as to major defense contractors and commercial manufacturers. dB Control designs and manufactures reliable high-power TWT Amplifiers (TWTAs), microwave power modules (MPMs), transmitters and power supplies with modulators for radar, electronic countermeasures (ECM), and data link applications. Acquisitions in 2019 and 2021 have added the following to the company’s product offerings: custom RF sources and receivers, RF and microwave components and integrated microwave subsystems. The company also offers specialized contract manufacturing and repair depot services from its modern 40,000-square-foot facilities in Fremont, California. dB Control is AS9100D and ISO 9001:2015 certified. More info: www.dBControl.com

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