Four traditional test approaches are used for radar system integration and test: delay lines, commercial off-the-shelf (COTS) FPGA-enabled instrumentation or RF systems on chip (RFSoCs), COTS radar target generators, and turnkey test and measurement solutions. Each of these test methods presents its own strengths and weaknesses.
Delay lines are robust and cost-effective solutions that are easier to buy and develop and that meet very low-latency requirements. However, they are very limited in capability and only work for simple system functionality testing. They don’t offer electronic counter-countermeasure (ECCM) techniques and simulations of real-world environments or scenarios that modern radars experience like clutter and interference.
COTS FPGA-enabled instrumentation or RFSoCs feature low capital cost, low-latency capabilities, and the flexibility to be tailored for complex systems with unique requirements. But they do require large human-related costs like nonrecurring engineering costs in initial development. Due to coding complexity, this instrumentation can be difficult to maintain and not always dependable. It typically is not true test equipment, so you have to do a lot of firmware and software work to get the system up and running effectively at the beginning of all new test programs.
COTS radar target generator systems have a lower nonrecurring engineering cost investment because of their higher-level software starting point and ability to be tailored to specific application needs. This allows domain experts to use their knowledge earlier in the test system design process. However, COTS radar target generators typically cost more, require support to upgrade and maintain, and lack flexibility because a larger part of their functionality is already defined. Their test capabilities are evolving more slowly, so you have to rely on test vendors to implement new modes or functionality for these generators.
Closed or turnkey test and measurement solutions are defined and delivered as full solutions, which results in great dynamic range, well-calibrated and well-known support based on a core COTS model, and the ability to be leveraged across multiple programs quickly. But turnkey test and measurement solutions are limited to vendor-defined functionality and are difficult to configure for unique system needs. They also produce higher latency because they are not optimized for a specific test, are typically not phase coherent, and are often prescripted or open-loop systems. Because of these challenges, you must rely on vendors to add new functionality for rapidly changing requirements, which results in a system that is very difficult to scale to multichannel RF systems for technologies like AESA and interferometry and limits your ability to conduct closed-loop test.
Figure 3. The industry trends rapidly changing new radar and EW technology are also making test instrumentation highly adaptable, software driven, and modular to address the need for more modeling and simulation testing.
The industry trends affecting new radar and EW technology are also driving new test instrumentation trends like industry convergence, software-defined platforms, test system maintainability, and test system architectures.
Test equipment vendors are typically serving more than one industry, so they can use instruments across industries like automotive, 5G, and defense. As the technologies and testing for these industries converge in our newly connected world, test instrumentation must expand frequency coverage and work at larger operating bandwidths with higher channel counts. Test and measurement vendors are investing more in software platforms to run their instruments and earning more revenue as customers quickly choose the flexibility, test speed, and reliability of software over previously manual test systems. In comparison to other closed-loop options for radar test, test equipment vendors can leverage their equipment in multiple industries and see economies of scale driving down test instrumentation solution cost while creating more capable test instrumentation.
The industry is showing that boxed instruments for test need to last 8 to 12 years. Firmware updates are required at 18- to 24-month intervals, and hardware upgrades likely occur every 18 to 36 months. Boxed instruments are emulating cell phone devices by incorporating touch screens with fewer physical buttons. To increase flexibility, boxed system manufacturers are incorporating modular devices in these systems for easier upgrades. They are also creating “super boxes,” or collections of boxed instruments, for larger test coverage from single systems.
Modular instruments are seeing the most growth in the industry with an increase in radio front ends, multiprocessor architectures, and reporting and storage needs. By using modular hardware and software platforms, you can adapt your test systems for a wide variety of needs, from faster design to reduced schedule risk to compliance with future and more complex system requirements. New modular systems are seeing improved flexibility with FPGA and RF hardware in the same device. This means you can use the same instrument to perform more types of test by switching between devices like a real-time processor, spectrum monitor, channel simulator, and DUT controller. With modularity also comes the trade-off of highly dense test systems for high-performance test systems. You can include multipurpose instrumentation in your modular systems if you can sacrifice test performance capabilities for additional functionality. Multipurpose modular measurement instruments also offer improved measurement IP, better components (especially analog-to-digital converters and digital-to-analog converters), advances in signal processing, and better software accessibility and architectures. In addition, modular test instrumentation has led to more compact test systems, so more than one box instrument functionality can fit into a smaller, PXI-based modular instrument or system.
Overall, test instrumentation is evolving to meet the needs of new radar and EW technology by leveraging and adapting to industry convergence, software-defined instrumentation, multipurpose test instrumentation, and modular test instruments.