WHAT IS A CRPA?
The acronym stands for Controlled Reception Pattern Antenna. CRPAs are designed to reduce the effects of RF interference or establish signals’ angle of arrival. Using multiple antenna elements, they minimize jamming signals, using null generation or null steering or maximize “truth” signals using beam forming or beam steering.
CRPAs are a very useful antenna system for platforms that need to operate in environments where jamming and interference are commonly present. For this reason, CRPAs are becoming increasingly common, particularly in the Defense sector. They are an extremely effective anti-jam/spoof solution, because they adapt dynamically in response to jamming or spoofing signals.
WHAT MAKES A CRPA?
CRPAs begin with some sort of multi-element antenna, but the real magic happens within the antenna electronics, where the RF then proceeds downstream to the GPS receiver. These items can be connected to each other in-line or in a single enclosure. Single-enclosure antennas are sometimes called “integrated CRPAs”. Fundamentally, they work the same way.
TESTING A CRPA
Testing a CRPA prior to fielding is critical − especially in applications like defense, where the stakes are high. There are several test methods for testing CRPA antennas. You should evaluate these methods, their costs and suitability for the use case to ensure that your needs are fully met.
The anechoic method is the only way to test an entire system as-is, because it allows testing of both the antenna and the antenna electronics integrated in a single package without modification. Still, it requires that the chamber be an optimal size to accommodate the device or system under test, and you could be limited by the antenna setup in the chamber.
Skydel auto-calibrates the system, maps the antennas, and is designed to streamline chamber setup and reduce the multiplication of hardware systems. Interference can be integrated with Skydel software or an external generator.
The wavefront method brings all signals for each antenna element to the antenna electronics via cables. It prioritizes the ability to have dynamic trajectories for the receiver and for the interference transmitter, which lets you do a great deal of testing. You can essentially model any scenario with an unlimited number of interferences.
A wavefront system is packaged lab-ready. Although it doesn't test the antenna, the important part to test is the antenna electronics, making it a good solution for testing CRPAs. It is the lowest-cost option considering all the variables. Be aware of any limitations such as signals, jammers and spoofers, and scalability for future needs. Skydel Wavefront is scalable from two to sixteen elements, is phase coherent, performs real-time automated phase synchronization, and has built-in jamming and spoofing.