Controlled Reception Pattern Antennas
Controlled reception pattern antenna (CRPA) technology is used to protect GNSS receivers, especially those used in defense applications, against threats such as jamming, spoofing, and other forms of interference. CRPAs are a form of beam-steering antenna.
GNSS satellite signals, including GPS, Galileo, BeiDou, GLONASS, SBAS and QZSS, are typically very low power signals. This makes them vulnerable to jamming, spoofing, and interference. These threats can be used to affect the PNT (position, navigation and timing) capabilities of military platforms such as aircraft and helicopters, UAVs (unmanned aerial vehicles), missile systems, ground and armored vehicles, and naval vessels.
CRPA technology mitigates jamming and spoofing threats by taking advantage of the fact these signals and legitimate satellite signals arrive from different directions, and can thus be spatially filtered. The systems use an array of individually controllable antenna elements to set up a pattern of beams and nulls, steering the beams in the direction of GNSS satellite signals and the nulls in the direction of interference. The antenna pattern is highly adaptable and can be changed rapidly to account for attacks from varying directions.
CRPA systems include a processing unit that performs the necessary calculations to set up the antenna pattern and combat the interference while having minimal impact on the required GNSS signals. CRPAs can replace existing GNSS antennas without the need to modify the receiver.
CRPA Antenna Testing
Jamming and spoofing threats to GPS and GNSS signals are constantly evolving, and so CRPA systems must undergo rigorous testing against the latest techniques. CRPA testing can be performed in the field under real-world conditions, which is highly realistic but costly. GNSS simulators can also be used to test CRPA systems, and allow repeatable and thorough test programs to be carried out.