Like commercial communications, radar and electronic warfare (EW) systems must now function successfully in an increasingly crowded and, therefore, unpredictable electromagnetic spectrum operations environment (EMSO). In fact, the radio frequency (RF) spectrum grows only more congested as these intentional aerospace defense systems intersect with everything else that might interfere, such as terrestrial broadcast signals, different generations of cellular communications, and satellite communications. Modern threats and countermeasures flood the modern EM spectral environment with thousands of emitters, including radios, wireless devices, and radar transmissions. This, in conjunction with advanced digital signal processing (DSP), creates a dramatically complex electromagnetic spectrum.

DSP led to advancements in dynamic range and algorithm complexity. This environment creates complex signal activity, leading to dynamic and evolving threats for EW and radar systems. While many of these systems keep pace with their environment via technology advancements, such as high-performance DSP and gallium nitride (GaN) amplifiers, the sheer number of possible scenarios from one threat creates difficult challenges.

Figure 1. Verifying the performance of rapidly evolving EW and radar increasingly demands systems that are multichannel and scalable with wide bandwidth capability.

To prove the performance of mission-critical radar and EW systems, developers increasingly face test limitations in terms of both cost and time. An alternative is to record their system’s performance with evolving radar recording capabilities, which makes it possible to gain crucial information to validate both EW emitter and radar systems (Figure 1).

The Win, on Record

Although radar recording has use cases for both EW and radar systems, their goals are different in that these systems are essentially vying against each other. When a radar appears to an EW system, for example, the EW system should evaluate it and potentially reprogram itself in a fast manner to defeat that radar threat.

From the radar system point of view, the goal may be to verify that the radar is advancing to mitigate newer cognitive jamming or EW capabilities. Radars have electronic protection built into them to mitigate attacks like jamming. Thus, their goal is to verify that EW systems cannot successfully launch an electronic attack against them. If the radar system sees proof of an attempted attack in the responses, it may react by switching frequencies or waveforms.

Figure 2. Software advances in radar recording enable capabilities such as multichannel, emitter scan pattern analysis using variable length segmented capture.

For both types of systems, simulating and recording these scenarios in the real-world signal environment offers a clear view into the systems’ responses and, ultimately, the outcome. If your radar system did not prevail, you can examine what approach you used against a specific EW platform to understand why it did not work. Understanding how your radar was defeated will help you make changes to your system so that it prevails in the EM spectrum environment (Figure 2).

From the EW system perspective, you are gaining that same intelligence. If your system was successfully jammed, you can see exactly what occurred and why your system failed to respond in a way that assured its success. You want to be able to document exactly what happened that made it work properly or fail to function optimally in each environment or situation.

Figure 3. Wideband, multi-channel systems designed for recording and analysis of pulsed signals include multi-channel, multi-bandwidth integrated RF recording, with real-time measurement of pulsed RF and hours of RF data recording storage.

By recording, you also may capture other systems lurking in the spectrum (Figure 3). In today’s spectrum environment, it is not sufficient to know that your system will prevail over opposing systems. You also need to know that your systems will remain effective when faced by unexpected signal events in dense signal environments. Within the operating radar environment, for example, the range of complexities may include ground clutter, sea clutter, jamming, interference, wireless communication signals, and other forms of EM noise. It may also include multiple targets – many of which utilize materials and technologies that present a reduced radar cross section. By recording the EMSO environment during testing, you can see what signals are present and what impact, if any, they have.

Burden of Test

When it comes to EW and radar systems, the testing process is exhaustive and expensive. Range testing a new fighter jet, for instance, demands a large investment. By limiting testing time and then closely evaluating a recording of that testing, it is possible to verify that you attained the measurement of interest and verify the response to it – whether you are validating that the system did respond properly or verifying that an improvement needs to be made.

For radar systems, it is essential to detect anything in the environment – unintentional or intentional – that presents as noise-like to the radar. By recording the EMSO environment in those dense environments while you are testing your radar, you can see:

  • Did my radar work correctly?

  • What else was present in that environment when it worked right or did not work correctly?

  • How does the radar respond in each scenario?

  • How is the radar system performing over time?

This knowledge provides confidence in radar performance in the presence of both intentional and non-intentional interferers.

EW Emitter Validation

Similarly, electronic warfare emitter validation is critical to knowing how your systems will perform in the EM spectrum environment. Increasingly wider bandwidths and agile signals continue to emerge, complicating this task. Emitter validation demands quantitative verification and validation from an intentional stimulus in the lab, such as an anechoic setting. The goal is to capture enough signals of interest over a diverse range of frequencies. Longer simulation and overall technique times need to be evaluated over longer frequency range and bandwidth.

The goal of such validation is twofold: acquisition and analysis. The priority in terms of acquisition is being ready to record – having overall system simulators and the device under test ready and coordinated for the overall scenario. The focus is on assuring that the correct scenario is being transmitted and received at the correct time to not waste lab time. In contrast, the analysis aspect is more concerned with examining the recorded data in detail for proper simulation, stimulus, reaction, etc. Through this process, the goal is to gain knowledge around points like:

  • Will the platform correctly operate and engage in the theater or operational environment?

  • What happened during a given scenario time?

Beyond their multifaceted forms and capabilities, EW systems boast high intelligence. With the increased use of adaptive programming, these systems continue to grow smarter. In response to observed effects on the battlefield, they will alter operation via radiated waveforms, techniques, or timing. Waveforms, in particular, change nearly instantaneously. As their responses become more intelligent, it becomes more critical to gauge performance thoroughly to predict the system’s response.

Facing an Ever-Complex Future

With the increasing complexity of the EM battlefield, accurately validating system under test (SUT) stimulus and output data to ensure correct operation is critical. This task becomes more critical as the systems themselves evolve quickly, incorporating new DSP techniques, architectures, materials, and approaches. These systems increasingly operate at higher frequencies as well and demand wider band-widths. Such complexity makes testing much more difficult. By adding radar recording capability, it is possible to capture and record signals of interest continuously through a test threat scenario to truly validate proper operation.

As these systems evolve, they also strive to reduce time to insight in today’s data-intensive world. For modern missions, timelines are short and the work only increases with complexity. You need tools that verify if all signals in the test scenario were acquired correctly, if the SUT responded correctly to the threat scenario, and if the correct signals were generated at the right time. The EMSO environment will only grow denser and more crowded. Without being able to predict everything in that environment, knowing how your EW or radar system will perform in the theater or during an engagement becomes a critical step toward prevailing in that environment.

This article was written by Nancy Friedrich, Aerospace Defense Industry Solutions Marketing, Keysight Technologies (Santa Rosa, CA). For more information, visit here .

Aerospace & Defense Technology Magazine

This article first appeared in the September, 2021 issue of Aerospace & Defense Technology Magazine.

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